Few months ago I experimented some with the edge of a curly maple board. I was comparing the planes I made with some LN that I also have (#4@45*, #4 1/2 @50*). All caused tearout in about the same amount, Then I put a near-zero-clearance-angle micro back bevel on the irons (all planes are BD). The tearout was gone with both angles. The difference was striking. It just could be he case with that particular board, so the evidence might not much value in general.
I got the idea for experimenting with clearance angles from thinking about the card scrapers (they do have zero clearance angle).
Here is now my ‘belief’: The action of an iron is actually that of ‘prying’ in addition to ‘slicing’, thanks to the clearance angle. The prying action contributes to the tearout. More: Some tearout (the actual breaking of the fibers) occurs behind the cutting edge. On a larger scale, the same happens often when you are splitting (riving?) logs for firewood, as the wood fibers tear behind the cutting edge of the ax or hatchet.
If anyone else comes across the same type of empirical evidence, I would like to hear about it. Near-zero clearance micro bevels could then be recommended asan additional way (to high cutting angles) to minimize the tearout.
Best wishes,
Metod
Replies
I am thinking (guessing)(but I have guessed quite a lot about this over the years) that the micro/near zero clearance causes the thin flexy area of the blade to dive down into the wood less. Probably more friction though.
I am guessing that the diving down then springing up can cause some tear out, and chatter. Diving down effectively momentarily increases the depth of cut. Picture using a scrub, deeper cut, with the grain and how that can tear out as opposed to cross grain with the scrub.
I like the micro bevel on the other, non-bevel side of the blade to increase the effective blade angle. On a bevel down. More fun (less time wasted making bevels in difficult places) to just use a bevel up.
Be ware that the surface of the wood can be overly burnished by too little clearance. Can impede finish penetration and glue adhesion. Larry says.
Seems like many years ago I found that I still got tear out in some purple heart even with wide sharpening angles on a bevel down and that was what got me into bevel ups.
Still later I learned and verified that a micro bevel on the non bevel side of a bevel down could prevent tear out even in my purple heart. Much more fiddle to sharpen though.
and another think (not a guess)
That your riving analogy May not always apply because tear out is partly from reversed grain AND the fibers are not consistently aligned like some nice rivable oak.
I admit to never in my life having riven any wet wood though so you are way up on me there.
me thinks
Metod,
First off, let me apologize in advance for my brain-dead lack of comprehension. It runs in the family, even the dog is suspect. Anyhoo, I'm have some difficulty putting in my mind what exactly is a zero clearance back bevel. After reading roc's replies, I'm still stymied. Could you please humor me with an explanation?
Thanks,
-Jerry
think of squaring off the back edge of your finished edge
Back bevel as I understand it it to put on your primary edge then you have angle at 45o ... think of it in the plane the plan's base is at 45o to the blade edge but the blade in the frog is at what eve rthe frog is at. .35o? so you carefully put a tiny micor edge on the back of the blade so that the 45o angle is meeting the wood at the plane bases angle 0o..
I think... maybe?
Richie
ROC --- Help I bought a Shoulder plane and am makeing a smoother!... Im lost!
Richie,
You are saying that the back of the iron is beveled at ~45 so that the blade presents itself to the stock at a ~90 right angle - like a scraper plane set at ~90? OK, I'm listening. I've back beveled a #4 with a ~12 - 15 micro to use on stock with reversing grain. Works just fine. Is this it, a ~45 back bevel?
-Jerry
Yea..
Id use ansi graphics but I guess that would go outthe window here now days...
I am far far from an expert but Ill try and explain it again as I under stand it...
You have flat iron in a frog that is 25o
your plane is at 0o to the surface.....
You cut a bevel into the blade that is 25o so that that 25 + the Frog's 25 = 50o angle of attack...
You micro bevel the blade's 25 to 27... and you have now 52o attack angle... the back of that 52 beautiful set up is just the perfectly flat 25o nothingness of the frog extended thru the blade... so
Some folks carefully chamfer (so to speak) that flat a micro bit) in this case it would be 38o so that when
the blade in inserted and lands it has a tiny bit of support. to the cut
Rich
Jerry.. First off, let me apologize in advance for my brain-dead lack of comprehension. LOL..
And about the dog: I and my very old dog are much alike...
Metod,
I have to join also with the question of "huh?" Is there some place I can read or see more about what a clearance angle is? I understand a 25, or 30, degree angle when sharpening a plane cutter. And I understand add a micro-bevel to that. But, I just can't understand what a "near-zero-clearance-angle micro back bevel is. I figure it is my brain that has the problem and not your writing.
Alan - planesaw
Clearance angle? Looks like this (below) ...
Take the clearance angle to an extreme - zero degrees. The blade will skim across the surface and not cut at all.
Now increase the CA by 5 degrees - if the wood springs back by this amount, then the blade will again not cut.
According to Leonard Lee (Rob's dad) in his highly regarded writings, the minimum CA needed is 8 degrees. By contrast, the current crop of BU planes have a 12 degree clearance, which is in the "safe" range, regardless of the microbevel that is added. If you added a 5 degree backbevel, it would drop the CA to 7 degrees. Borderline.
A BD plane with a 45 degree frog and a 30 degree bevel will have 15 degrees CA. Increase the bevel to 35 degrees and the CA drops to 10 degrees. A 40 degree bevel will take it down further to 5 degrees and the danger zone.
Even a router plane blade has a clearance angle. If you wanted to make a router plane blade out of a hex key, you need to grind back for a cleance angle.
See here for an OWT I built: http://www.inthewoodshop.com/ShopMadeTools/OldWoman%27sTooth.html
Regards from Perth
Derek
Derek,
"the minimum CA
Derek,
"the minimum CA needed is 8 degrees"
Should I feel bad that my experience violated this 'theory"? Next time I will instruct my uneducated boards how they should behave according to some 'highly regarded writings'.
Best wishes,
Metod
Oy Metod, why the attitude? I was responding to "what is a clearance angle?", not your original post. I haven't got to that one yet - should I bother?
Regards from Perth
Derek
Derek,
I am sorry. Poor choice of words. Your (quoted) minimum angle did not agree with with my brief observation.
Best wishes,
Metod
Derek's explanation
Derek,
Thanks. Well writtne and illustrated. I now comprehend a clearance angle.
Alan - planesaw
The confusion may come from the word "back"
I think, strickly speaking if we leave out the word "back" then we have a micro bevel on the regular bevel.
The bevel is down next to the wood.
If the main bevel were parallel to the bottom of the plane there would be zero clearance angle. A regular bevel has like a fifteen degree clearance angle.
The blade is angled, beded, at 45°. Take from that a thirty degree bevel, sharpened onto the blade by the manufacture. That leves fifteen degrees clearance. Put a micro bevel on that of 10° and you get a 5° clearance. Put a 15° micro bevel on in stead and it probably won't cut wood for more than a pass or two.
Zero clearance is part of the condition, on a microscopic level, of a dull blade and why it stops cutting.
If you have a membership here you can look up past mag articles on blade geometry. Here is one of my favorites
https://www.finewoodworking.com/SkillsAndTechniques/SkillsAndTechniquesPDF.aspx?id=2091
Jerry,
The 'back' part applies when you have a bevel up arraingement. With bevel down 'back' indeed makes no sense. My apology as I was sloppy.
Best wishes,
Metod
Metod,
I like your experiment but it would be a good thang to be very specific; and also to show a pic or two.
How "near-zero" is that clearance angle? What is the specific number of degrees of that downward facing bevel above the wood surface?
When making your experiment, did you keep every other parameter the same? It would be easy to mistake an improvement in tear-out performance as due to the mechanics of the down-bevel when it might be due to a lesser blade projection, for example. Or a closer mouth; or just a sharper blade; or how you swooshed the plane. Experiments are not easy to design in which every parameter is known and controlled.
Your speculation about the action of the bevel as being like an axe-cut and so forth has all the attributes of a guess I'm afraid. Of course, some guesses are educated and some are just wild............ :-)
Lataxe
Sounds like cabinet maker's yoga
" downward facing bevel " Sounds like a yoga pose. There is one called downward facing dog pose.
http://www.youtube.com/watch?v=10WWIB6aWqQ
But I am guessing. A wildly educated guess but a guess non the less.
I was educated in the wild. The wild, wild west to be exact. As a mater of fact the neanderthal can still be spotted here. Long thought to be extinct.
Lataxe are you a woodworking Yoga master ?
Flexing One's Parts
Roc,
My ole body has never been too bendy, even when I was young and excessively juicy. Those joints and tendons all have stops built-in. So....
I had to compensate by making my head internals very flexible indeed. This is easy as it just takes daily exercise in the meme-gym, which is distributed throughout meta-space, as you know. Here we are down one particular ginnel, for example, flexing the conceptuals concerning blade geometry. I find it quite easy these days to lift up any concept and bend it into different shapes. Like making animals with sausage-balloons.
Of course, some of those sausage-concepts turn out to be more mythical than real - harpies, gryfons and dog-headed men. Possibly a number of them have survived and made their way to Colorado? There certainly seem to be a lot of unnatural concept-beasts around in the Western world as a whole. Some are elected as heads of government, despite being obviously a dog's head on a snake's body.
But I digress.
Where is Metod with the hard facts?
Lataxe, a meta-kontorsionista
Lataxe, You should tell
Lataxe,
You should tell from my description that the 'experiment' was not one in the proper scientific sense. On a whim, I tried something and noticed a substantial difference. I did point out that it was just one board, as to avoid any general claims. If anybody wishes to give it a try, and finds any value or not, so be it.
All I did was to advance the irons by about (I did not measure) 1/32", and took a few svipes with a stone (put minor sctratches on the soles - should put some protective tape on one end od the stone...) . That created a near-zero clerance angle. I was pleased with the resulting surface. Easy to reproduce and collect independent evidence.
Yes, I was 'guessing' (considering the structure of the wood - that would qualify my guess as a conjecture...) what could be behind the differnce.Your guess might be different. Some never try to guess what could be behind an observation.
Best wishes,
Metod
Re: Clearance Angles
Interesting.
I thought that wood is sort of visco-eleastic material. One of the consequences it that wood springs back after planing. If you measure the thickness of your board after planing, measure the thickness of the shaving and add them all up, you end up with a value that is thicker than the original thickness of the board.
In other words, you can't plane with zero clearance.
Or in the words of Christian Morgenstern: "Und also schloss er messerscharf, dass nicht sein kann was nicht sein darf".
Chris,
My irons did not have 'exactly' zero-clearance angles, more like 1-2 degrees.I am aware that wood is visco-elastic but am not equipped to measure practical effects. From my (naive, uneducated - no engineering background) view is that micro-attributes have measurable effect on micro-scales, but could be irrelevant to large-scale situations. Sort of like special relativity: very important at high velocities (no functional GPS without taking it into account), but completely redundant at small velocity applications.
Your picture could suggest that (add a bit of a near-zero clearance bevel) the springback due to visco-elastyicity is simply delayed by the amount of the microbevel.
I have no stake in 'defending' my conjectures. I am not forcing anybody to try it, neither can I influence the outcomes. Maybe my particular board was a miracle - and they are known to be irreproducible <g>. Apart from the 'miracle designation', the question (for me) is still open: How come it happened? Of course, if visco-elasticity is a statistical concept, then the outcomes of individual trials have little significance. Maybe (not woodworking, though) we should have a word with the folks living longer than our (national) life expectancy :(
Best wishes,
Metod
Metod,
Enjoyed the thread immensely - the interpersonal fun as well as the mental gymnansics and the linguistic challenges. I remember reading something by Chris Schwartz, commenting on BU vs BD in regard to tearout on curly maple.
Page 162 of his "Handplane Essentials" discusses "The 17 degree difference" (45 versus 62). He likes "62 degrees" for getting rid of tearout, regardless of whether it is on a BU smoother where the bevel 50 deg, or a BD smoother which has a backbevel to get you up to 62 deg (or as close as you can get.). Chris concludes "I guess what I am trying to say is that is is not so much the tool as it is the angle."
I was in the middle of reading Chris' book when I saw your thread. The book is interesting, more because of its approach, than because of its conclusions. Chris' approach is exactly what you were doing -- try alternatives. If I were to take a lesson away from Chris' book, it would be, "don't bother to read too much. Instead, do as I do, and try a lot of alternatives and see what works for you." Chris is exceptionally wordy, but then again, he is more of a writer than a woodworker. By that, I mean that he doesn't make a living by making furniture and selling it, but by concatenating words and selling those.
Have fun.
Mel
Mel,
Thanks for 'moral support'. I learned much from reading various sources. I am curious about what works well and try to understand why it works the way it does. The 'understanding' component of woodworking gives me much satisfaction. Given a choice between some theory and corresponding empirical evidence, I prefer the latter.
Best wishes - it is a good day,
Metod
Mel you know I enjoy your work and writing but
Every time I hear or read some one say:
"don't bother to read too much. Instead, do as I do, and try a lot of alternatives and see what works for you."
I can't help but think about chemists, electricians, mathematicians insert your own science dude or dudet
and I think . . . what if they did not apply known formulas but just experimented wildly. . . what a waste of time. Would be a lot of dead and maimed folk. Too. If the FORMULA has been discovered why not use it and build on it to learn more.
then . . . then . . . wait for it . . . publish the results of the latest discovery for those coming up.
Or are woodworkers continually and helplessly getting caught in many mutually exclusive dimensions and so what one finds in one does not apply to another ?
Well . . . this does tend to happen where I work (hmmmm) . . . but not in my home work shop.
Or maybe I don't understand the point. More often than not if I read something that works for a highly experienced exacting observer of this woodworking thing and I implement it I can duplicate the same out come in my shop.
"Exacting" being a key here.
Lataxe,
Hi, I didn't get a notice that you responded. Enjoyed your reply. "when I was young and excessively juicy " awe those were the days ! Not being as flexible as I once was I really payed for it when I hit the cat a year ago on the bike. Shproyng ! I gotta get back into the yoga thing or use the Japanese tools/benches more.
Every one,
Zero clearance doesn't cut. Nope not much but keep in mind the high points of the surface may be nipped off ( cut ) sort of until the microscopic arise (sp) rounds over . Depends on the rigidity of the machine doing the cut. How big are your triceps ( and how much ballast is in your trunk) ?
: )
just trying to keep the argument going.
Metod wrote, "Then I put a
Metod wrote, "Then I put a near-zero-clearance-angle micro back bevel on the irons (all planes are BD)."
Later Roc replied. " Every time I hear or read some one say:
"don't bother to read too much. Instead, do as I do, and try a lot of alternatives and see what works for you."
I can't help but think about chemists, electricians, mathematicians insert your own science dude or dudet
and I think . . . what if they did not apply known formulas but just experimented wildly. . . what a waste of time. Would be a lot of dead and maimed folk. Too. If the FORMULA has been discovered why not use it and build on it to learn more.
then . . . then . . . wait for it . . . publish the results of the latest discovery for those coming up.
Or are woodworkers continually and helplessly getting caught in many mutually exclusive dimensions and so what one finds in one does not apply to another ?
Roc, what a splendid post! I agree completely.
Metod, I took the time to try and visualise your experience - I cannot call it an experiment since you have not included data that I might reproduce, and I do not know, in fact, if you could do so as well. Anyway, I can up with two possiblities to try and understand what you had done ...
I wish I could insert a picture so as to discuss it more coherently, but for the time this is it.
So is it Figure A or B?
Fig A will not work, and Fig B is the same as a scraper.
Regards from Perth
Derek
p.s. apologies for the tiny graphics (limits of Paint)
Derek, As I mentioned
Derek,
As I mentioned earlier, my use of term 'back-bevel' was wrong, as it applied to BD bedded irons (it would be correct for BU).
As I posted to Lataxe, this is what I did: Extended the irons by about 1/32"; made a few swipes with a stone (right on the plane), then (forgot to mention to Lataxe) a few strokes on a strop. This was the quickest way to create a near-zero microbevel. That's all I did. There are no other data. If the iron would be mounted BU, then the same procedure should be, I think, equivalent to the 'ruler trick'. So, exactly nothing new. Quick, easy and inexpensive to reproduce <g>.
Looking some more at your sketch, I can see a possible cause for misunderstanding. The upper right version would result, if the stone and the strop would contact the sole in front (toward the toe) of the iron. If you rotate your lower left example about the cutting edge so that the backbevel is nearly horizontal (parallel with the sole), you get a near-zero BU situation.
Eventually I will experiment some more - with different boards/lumber. Others can do it before I get around. This is what I will be looking for: if the near-xero clearance angle has a wider merit (and under what circumstances), then the stropping between the honings can be sped up: extend the iron a bit, strop (drag the plane over a strop - backwards), retract it to the desired cutting depth, and back to work. This way, the plane itself serves as a stropping guide, giving a constant stropping angle. Of course, maybe too nice/convenient to be empirically useful.
Best wishes,
Metod
Comparisons
Metod,
Sad fellow that I am, thoughts about your experiment have been occupying my idle moments as various mental picksherings are made of what might be happening at that edge where it meets and cuts wood. However, it's unwise to reach conclusions from mere mental experiments, even if they might suggest actual experiments worth doing.
But for now might I mention a couple of comparisons?
You compare your near-zero clearance angle to a ruler-trick back-bevel but the two are dissimilar. The ruler-trick barely changes the slope of the blade-back (a fraction of a degree is what's wanted) whereas your procedure is changing a 45 degree clearance angle to a near zero angle. The similarity between the two is just that both provide a very thin line of straightness/polish on one side of the cutting edge of the blade, making 50% of the sharpy (the other 50% coming from the polished bevel side of the edge).
A better comparison might be with a chisel, where the chisel back is often used to jig the chisel as it cuts, ensuring it doesn't dig in. In that case the clearance angle of the chisel-back at the cutting edge in not just near zero but actually zero.
So, when using a chisel in this way does it's back prevent a cut via disallowing the edge to reach down to the wood fibres? Well....sometimes. If the chisel is aimed at a significant pertruberance there is no issue. But if the chisel is being used to pare a section of an already flat surface (eg using a cranked chisel to deepen a groove slightly) then it is often necessary to tip the chisel up a little before it will bite, after which it may be lowered again to actually pare off, plane-like, a thin slice of wood.
You can't do that initial lift-to-get-a-bite action with a plane should it's blade clearance angle be zero, unless the blade is sticking out a lot - too much to take the usual thin shavings. However....
If you picture a very slight protruberance of a near-zero clearance angled blade from the plane sole, you can imagine the blade compressing the wood fibres enough to allow the edge to bite, if the back bevel making the near-zero clearance angle was of your hairline type. If the back bevel is too wide (more than a hairline or two) this would increase the pressure needed to compress the wood enough to allow the edge to bite, to the point where that pressure would require three strong men (or even some strong wimmin) leaning on the plane to manifest.
***
Well, there is some educated guessing. As Mr Williams mentions, a full lab test is now needed. As I am busy with a heavy schedule of self-indulgent pleasures just now, I nominate you as chief scientist and lab teknishin. :-)
Lataxe
Sir..
I am filled with dismay at the very idea of anyone using a shovel to move mushroom compost as this practice was made illegal in 1581 by the then Lord Chancellor..
I thought our dogs were only allowed to dig them up?
Lataxe.. I think your speling of protuberancemis is wrong....
No hate here.. Or was that Protuberance? Not sure here.........
This is what I thought he meant
PS: I clarified my drawing a bit. Darned if I can figure out how to convert it to one of the file extensions from the list. All I can do is PDF.
Can anyone open it ?
yep
"Can anyone open it ?"
Clicked on the link, and it popped right up.
Metod isn't asking for anything that would be a problem for those who've developed a reasonable amount of skill in their sharpening. I've been hoping a number of people would experiment with clearance angles and I've stayed out of this thread because I would like to see what people experience in their own experiments. I've posted about my own experience a number of times and my comments have been mentioned in previous posts. I'm posting to bump this and to add that I'd also like people to experient with their control of depth of cut at the different clearance angles. It'd be nice if they also experiment with a few different types of wood and report back.
Larry,
I meant my post to be 'empirical-provoking' (as you are suggesting) but all the thinking that it generated must be good for the mind.
After all, it was just one small board. :)
How much (effectively) does wood really compress during planing? The downward planing force divided by the area of the sole in front of the iron yields a rather small pressure - probably not enough for any measurable compression even in very soft woods (balsa?). An iron contributes to this pressure only when a cut starts away from an edge, and then only for .002"-.005" (depending on the depth of the cut).
Best wishes,
Metod
You didn't ask me but
. . . it seems to me the compression happens at the blade edge (which is bellow the plane sole). Since the area is soooo small on that "knife" edge it can compress and penetrate at the same time. As the area is smaller the force over that area must be greater per unit.
NOW . . .
since you made your "knife" edge have effectively a larger area with the secondary bevel facet angled right down on the surface it can not compress/penetrate as easily. Compresses/penetrates to a more limited degree (amount). More area less force per unit.
I am sure by now I have offended all the engineers with my affazzed lingo so I will stop now.
PS: Ooops a bit more: That means the plane can actually ride up on the blade with the front of the plane sole actually a microscopic amount off the wood. YES ; I believe I have experienced just this in extremely hard wood and a dulling ( dull ) blade.
Roc,
I was thinking along your lines, but now I am not so sure anymore. Larry is right when he says that I do not understand the details. Vaguely, there are several forces at work: visco-elasticity, friction (part of it might also come from visco-elasticity) and the force exerted by the 'operator'. It would be nice if somebody could draw a detailed force diagram, accounting for all the forces near the cutting edge.
Larry's example of poplar and maple is (to me) a good one, and should (hope) help with my thinking, if not planing ;).
Eventually (or not...) I will come to terms as to why the quality of the cut changed with the reduction in the clearance angle in that particular board (I haven't done any more experiments since)..
Take care,
Metod
Metod, Roc has it right. I
Metod,
Roc has it right. I don't think you understand the deflection of the wood fibers. It's not the result of the sole's toe area pushing down on the wood, it comes from the wood fibers resisting being severed and being bent in the direction of the cut.
To experience this deflection, set a well tuned and sharp common pitch plane for a very light cut in a dense wood like hard maple and then with the same setting try to take a cut in a less dense wood like poplar. You won't be able to get a cut in the poplar because the wood will just deflect away from the cutting edge. If you reverse this and first set for poplar you're likely to tear up the maple from too heavy a cut.
The spring back from the deflection is more difficult to demonstrate but it's what causes the sort edge life of 12º bevel up planes. The wood fibers rub on the back of the cutting edge and accelerate the wear to back of the cutting edge. The more obtuse the bevel angle the more deflection and the more wear to the back of the cutting edge. Then some suggest using the "ruler trick" for these planes and only make the problem worse because this further reduces the clearance angle. Also at the more obtuse angles some suggest for the bevel of these planes the wood fibers are so displaced and spring back with such force that it actually limits your depth of cut. Can you make a plane set up this way to take a heavier shaving? Well, yeah but you really have for force it. You don't want to work this way, it's a lot of work and you really don't have much control when forcing things this way.
I think I remember you made at least one bevel down plane with a 55º bed angle. If that's the case, you can get an idea of the lifting force of these wood fibers when they spring back. Use a moderate wood like soft maple or cherry and hone the iron at 30º and everything will be fine when set for a normal shaving. Hone it at 35º and, even though the plane is sharp, it'll act dull. The plane will seem to want to balk and chatter. Here you have a 20º clearance angle and that's just not enough with an obtuse iron bevel and a 55º angle of attack.
I really don't care what Leonard Lee's sharpening book says about clearance angles. His 8º is simply not adequate and you can prove it to yourself if you experiment as I have.
Larry,
Please see my reply to Roc - it is meant for you too. Thanks for taking your time and insights. Again, your illustration with maple and poplar is a much welcome one. It sure provides for a more thorough analysis and better understanding.
Take care,
Metod
Much e-ink had been spilled, and I am still slow in my understanding. I had some 'answers' to my original observation, but am not sure anymore. Things also got out of focus, so let me try again:
I noticed (it was only a small board of curly maple) that reducing the clearance angle to near zero, the (substantial) tearout , caused by the same irons earlier, was completely eliminated.
Any suggestions for why this would happen? I am not interestyed in reasons as to why it could/should not happen - because it did.
Best wishes,
Metod
You made your blade so it barely can cut at all
let alone dig in and gouge out hunks.
Here is a recap:
the micro/near zero clearance causes the thin flexy area of the blade to dive down into the wood less.
since you made your "knife" edge have . . . a larger area with the secondary bevel facet angled right down on the surface it can not compress/penetrate as easily. Compresses/penetrates to a more limited degree. Can't dig deep enough to cause tear out partly caused by blade flexing chatter.
I must have missed your post varifying Yes or No that my drawing was depicting what you described.
Makes it a little tough to comunicate if the discussion is too one sided.
Did you read the past mag articles on blade geometry ? Including
https://www.finewoodworking.com/SkillsAnd...
If so do you have questions about what you read ? If didn't read it then the ball is in your court.
Seems like I can't post without a PS:
Think of a snow shovel. Before the "back, forward, under, over bevel "(sorry couldn't help it) you had the equivalent of a snow shovel with the handle raised high and the front most edge able to dig in to the snow even if crusty .
Then you added your , lets call it a " geometrical modification" . This was the equivalent of lowering the snow shovel handle so now the curved part of the underside of the snow shovel can slide along on the driveway and keep the edge of the shovel from catching on that crack in the concrete . You know the one. The shovel hits the crack. You can't stop as quick as the shovel blade so the end of the handle buries its self in your crotch. Pretty soon you learn to lower that handle before you get to the part of the drive with the edge stopping crack.
You don't always have the handle low because then you can't shovel that crusty hard snow; the shovel just glides over like a ski.
: )
Got it ? Yes ? Good !
Lataxe,
Comparison with the ruler trick - ask me how thick is my ruler <g>.
Are you a scholastic (type of thinker)? Or is it this one of your lesser moods? :)
Take care,
Metod
Roc,
Thanks for reminding me of that article, and for your useful (to me) analysis/examples.
Best wishes,
Metod
My understanding of this discussion is still developing, but I think I understand the following: If I'm working with a standard 45 degree frog I can sharpen the blade at 30 degrees (maybe with a micro-bevel, maybe not) and I'll have a clearance angle of 15 degrees which should be adequate for normal work. If I sharpen that same blade at 33 degrees, and put a 2 degree micro-bevel on that edge I'll have a clearance angle of 10 degrees which is approaching the limit of a blade/frog combination that will actually work. I suspect that any further reduction would result in more frustration than satisfaction. Your mileage may vary...
Regards,
Ron
Ron,
I agree with your description on how to obtain various clearance angles.
"I suspect that any further reduction would result in more frustration than satisfaction. Your mileage may vary..."
Well, my mileage did vary. Also, I did not find the elimination of the tearout frustrating at all...<g>.
Best wishes,
Metod
Metod,
Your thread is the only one on Knots currently which has both an interesting woodworking issue, and a good deal of discussion. I haven't found any other interesting topics, and the only other thread with a lot of replies is about why nobody is posting on Knots any more.
In my response to you, I said that I liked your approach of trying things how to see what works, and I commented that seemed to be Chris Schwartz's approach to figuring how what works. Of course, I took some hear on that from some of our luminaries. Regardless of that, I still like and use the same approach you do. I try things to see what works. Later others or I can do some figuring as to why it worked. That was your original post. You tried something and it reduced or eliminated tearout. Then others got into a theoretical argument about why that wasn't possibe, or something like that.
You said recently "Well, my mileage did vary. Also, I did not find the elimination of the tearout frustrating at all.." I loved the tone and content of that statement. You have remained centered on the fact that you did something thatt worked well, and are happy with that. I, for one, do not argue with success.
I also loved your response to Lataxe on the ruler trick, etc.
Just wanted to let you know that in the current wastland that is Knots, your thread has offered an oasis of memory of what the old Knots was like. It had topics of substance, contradictory views being displayed, people with attitude, people coming up with irrelevant responses, and some folks adding light where once there was only darkness.
GREAT THREAD. I am very happy that you are not one of the folks who left Knots. I like your attitude towards woodwork. (That and $4 will get you a cup of coffee at Starbucks.)
Please continue to try things and to post what works for you.
Enjoy,
Mel
Mel,
I still like Knots. I preferred the old format, but as long as at least afew pleasant folks hang around, so will I.
Thanks for nice words.
Take care,
Metod
Metod,
I'm wondering if you've experimented any more with those clearance angles? Experimentation is good, especially when informed by some form of intelligent guidance, principles, extant knowledge and previous experience. Some lads apparently think the scientific metod :-) is no good compared with random mucking about driven by fanciful imaginings (or more likely, ancient tinpot "wisdom" long ago put to the side, even by olde wives).
Now, I am wondering if you have nailed down some of the other variables that may be set at this or that value during plane use, to isolate the variable (the clearance angle) you are interested in? If you read the Brent Beach stuff, he offers quite a good model for this approach. Some lads detest ole Brent as he deals in hard facts and often upsets those clinging to ole wifey tales, especially those arrogant enough to have tinpot theories that are derived by taking agin the proper knowledge of more famous innovators, inventors and practical experts. However, use of Mt Beach's findings certainly improves one's planing, which is what matters.
I will not be trying the Melicious mode at least (whatever it is - it is never elucidated beyond "just bugger about randomly like moi")
*****
An issue I would like to examine in the scientific way concerns that wear bevel; and whether (as kinda intimated in your original post) it can be polished up by one's planing action to help delay the moment of "blunt"? I often drag the plane backwards after a swoop without lifting it from the workpiece. Does this increase the blunt-causing wear or does it polish up the wear/back bevel a tiny bit every backstroke, to help keep the edge sharp? I don't know as that bluddy A2 stays sharp for ages no matter how you abuse it.
This "dragback sharpening" idea could be an educated guess or a rather wild one - but like your own experiment perhaps worth investigating. What a fine thing would be the lazymansdragback sharpening method!
****
Meanwhile I am heaving something of a sigh of relief that a certain wild guesser and arrogant dismisser of the scientific method is no longer around them spacecraft. One does not want one plunging from the sky because some nurk thought he'd try an elastic band instead of a rocket motor.
Lataxe, no solipsist, so fumbling about at the edge of an enormous blade of previous knowledge, honed by thousands of clever folk down the centuries.
Lataxe, I sent this to you because I don't want Mel to
think I am jumping on him to pick on. Where is that "To All " button we used to have ? I want to say to all and to the OP about:
>do not argue with success<
that when the clearance is brought back up and a true back bevel is put on the top side of the blade it will be the equivalent of . . .
well imagine finding an automobile and one has never driven an automobile but has seen it done once long ago in an old foreign language news real. Now the person gets in and messes about with the controls and gets it started. The owner's manual is on the seat in the language of the "experimenter" but he decides to ignore that for the sake of "adventure". I want to say more here but have self censored.
The problem is our driver has had what he calls success in that he is going down the road at twenty five miles an hour and is running his errands and picking up the kids at school so that sounds pretty good doesn't it ?
All the while the people on the outside of the car observing his progress who actually know the practical performance limits of the automobile are, with an amused look on their face, wondering why this guy is driving down the road backwards everywhere he goes.
Was that too mean ? I don't intend to get too personal here with Mel or Metod. It is just that once a guy learns what the car is all about and someone asks why then does it work so well the way I do it (going backwards every where) then what can one say to that?
PS: just wait till you discover forward gears and oh there is that turbo thingy but we won't use that yet.
Roc,
Have enjoyed your posts in this thread thoroughly. You bring me back to the old days.
Suggest you read Thomas Kuhn's "The Structure of Scientific Revolution". This is one of the best books I have ever read, and it explains the difference between "normal science" (essentially what Lataxe is talking about) and the revolutions in which existing paradigms are thrown out because they no longer fit data which is come into existence.
Revolutions occur when scientists come up with new ways to think about things that they have experienced but which don't fit the existing paradigm of the day (normal science). THIS IS THE EXCITING PART OF SCIENCE - having a creative mind to try new things and to see where current thinking breaks down, and how new data can be explained.
What Metod did was to come up with some new data. He, as any good scientist would, pointed out that it was a limited sample, and needs further test. Further testing would take two venues:
- 1 - is to try what he did on different pieces and types of wood to see if the phenomenon can be reproduced..
2) - to try to develop hypotheses as to why this happened (if it turns out to be reproducable).
Part 1 is kinda dull. Just work. Anyone can do it.
Part 2 really is fun stuff. It requires a high degree of creativity. You know, folks talk about "thinking outside the box". The trick in science, is to try to think outside the paradigm, to see what a deeper understanding of reality might look like.
Metod's original post was mone of the few really thought provoking posts of tne new Knots era. You have proven that with your prolific outpourings of ideas. I was happy to see Larry jump in because of the sheer breadth of his experience, and his creativity in tool design make him a natural for deep thinking on this issue.
This has been a GREAT THREAD. Keep on postin'.
And read the book. You can get it at the library. You are a creative guy who can wrap his mind around bicycles, woodwork, metalwork, etc. I believe you will be excitied by what you read. Science is crowded with scientists who know the scientific method, and spend lifetimes doing experiments which no one can criticize as being against the scientific method. However, because of their lack of creativity, they never ever even attempt to make the big jumps.
THIS IS WOODWORKING. LET'S MAKE SOME BIG JUMPS.
Have fun.
Mel
Books and stuff
The Structure of Scientific Revolutions by Thomas Kuhn's
Hey it is even on Kindle ! I may give that a whirl.
> BIG JUMPS<
Time to merely use what works. The research has already been done for hundreds of years. Basically metod "created" a mostly dull blade. I fail to see the breakthrough. The problem is with a mostly dull blade . . .
IT AIN'T GOING TO CUT VERY LONG
if the little plank were as large as a table top the blade would have , when it quickly dulled further, started just sliding over the surface and burnishing the whole thing all to ell.
But then we already said that. When I ran much I absolutely could not stand running around a track. Give me a trail where most all the foot falls must be right or one winds up cartwheeling or sprains/breaks an ankle. Trail running, at least on Pikes Peak, down hill, is reminiscent of a chess game. One is looking and planning ahead yet making present moment foot strikes and changing as the situation gets clearer.
I feel like I am running around a track here.
Lataxe,
No further experiments, as I am rather busy these days with other stuff , some of it being actual woodworking :) .
Brent Beach' aproach is completely to my liking, sort of "just facts, Sir" (that's American non-royal term of endearment).
Your idea of 'backdrag sharpening' is worth investigating. Maybe it would be even more efficient than 'externding the iron a little and backstropping that I mentioned earlier in the thread.
Oh, if you get favorable esults, do not <g> post them here as they might not fit some of the answers that you might be getting.
Take care,
Metod
"...Brent Beach' aproach is
"...Brent Beach' aproach is completely to my liking..."
Which may explain your experience. Even a scraping cut with sharp edge with inadequate clearance angle may well work better than a "faceted blunt edge," as someone arond here once pointed out.
Larry,
I like Brent's approach to empirical evidence. He seems to be aware of the difference between facts and fiction. Ron Brese (a fellow planemaker of sound reputation) suggests essentially the same sharpening process that has been on Brent's site for several years. I am just covering up up for my poor honing technique with intermittent stropping. I am happy with the results.
As far as my 'experience', I did not tell the wood that I like Brent's approach. Maybe something else could explain it. <g>.
Is it possible that card scrapers actually operate at very low clearance angles?
Best wishes,
Metod
"...As far as my
"...As far as my 'experience', I did not tell the wood that I like Brent's approach. Maybe something else could explain it. <g>...."
Are you sure? I think you may have when you created your control surface with tear out. I'd rather avoid discussion of Brent's methods because I'm at a loss for anything positive to say other than he is creative.
Larry,
"I'd rather avoid
Larry,
"I'd rather avoid discussion of Brent's methods because I'm at a loss for anything positive to say other than he is creative."
Without a doubt, the best line on Knots in the last five years!!!!!
Dorothy Parker would be green with envy for not having thought of that line herself.
Here is a question for you. How did the furniture makers of old reduce or eliminate tearout in difficult wood. Did they go from common to York to Middle to Half pitch in steps, or did they just go all the way in one step, or resort to scraping, or all of the above?
If you were smoothing a piece of Birds Eye maple, what would you use on your first attempt, and what would you move to if that didn't work?
I have a Lie Nielsen 4 1/2 and was thinking about getting a York or a Middle pitch frog for it. I have no experience with such angles. Do you think either would be more effective in reducing/eliminating tearout on Birds Eye? IF so, which would you go for? I am asking for comments on preferred pitch, not on the LN company. I am merely trying to make an informed choice. Since I don't have any experience with the higher angles, I am looking for advice. I suppose I could consider a bevel up smoother with a high angle bevel on the iron. In your estimation, which would be more useful, a BU smoother, a BD with York pitch or a BD with MIddle pitch.
Thank you.
Mel
Mel,
Traditionally woodworkers matched the pitch of the plane to the wood they were working. The best way to deal with tear out is to avoid it in the first place and going through a series of ptiches would initially cause tear out in difficult grained hard woods.
Using a smooth plane, when working stock by traditional hand tool methods, is all about minimalism and control. The faces of the wood are at their truest and straightest after the trying plane and it's best to avoid the smooth plane all together if possible. The smooth plane is going to introduce inperfections in flattness and straightness of the stock but is done locally and sparingly to deal with tear out or other very small problems. If you're waiting to deal with surface quality until you have the smooth plane in your hands you're in trouble and have lost control of flatness, thickness and straightness.
With this in mind, I don't understand why everyone seems to want to shove some road grader width smooth plane over their stock. I wouldn't generally have much use for a #4 1/2 width plane and certainly don't feel in full control when trying to take such wide shavings. Remember, control and finesse is what we want. Give me something more in the 1 5/8" to 1 3/4" width and for a wood like bird's eye hard maple I'd want it with middle pitch or 55º. Half pitch, 60º, would give even better performance if you could keep the iron sharp but you'll spend as much time sharpening as planing with a half pitch plane.
The other thing that I suggest is using a good iron that you can get sharp and keep sharp. If you have an A-2 iron in your plane replace it with O-1.
Best line on Knots
There really needs to be a page for quotes and one liners. If the thread wouldn't go the way of all the great material that was recently "lost" when the great change came I would start one.
Lets not forget the :
digging for a worth while truth here like a little boy with a shovel in a room full of horse manure saying to himself " I know there must be a pony here some where ".
Ha, ha, ha, aaahhhh, Ha, ha, ha, ha
Roc,
Well, Metod's thread is even now being hijacked by two blitherin' 'waymen intent on discussing a plane blade matter akin to that other issue concerning how many angels can dance on the head of a pin. (The number varies with the size of the pin, how rounded the top is and what it's coefficient of friction is, as well as that of the angel-boots - or do they wear slippers? And then there is the matter of which religious cosmology of the 491,077 current on Planet Erf is the correct one; or indeed if any of them are. Each specifies a vastly different number of angels, not to mention angel-types and roles).
But I digress.
Now, I have adopted this word you utter wthout grasping it's full meaning:
" Feel free to now tear your hair out and blither".
This sounds like some orthogonal of blatherin', which I am very good at (PhD in fact) but I need the korrect and unequivocal definition of "blither" so as not to do a blother when intending to blither; and thus commit a faux pas. Incidentally, I never tear out hair as it is already less numerous than heretofore. Also, I am allergic to pain unless it involves a bicycle.
As to these fellows and memeplexes that fail to include the self-critical mechanism, let alone a bit of basic introspection ...... well, they will eventually implode, explode, ossify, wither or meltdown from the brain-thrash caused by illogiking over-much (like a fragmented hard disk with bad sectors and too much data). Unfortunately the flying shards and goo often impinge upon we innocents. Also, fellows who have got aboard the fatally-flawed edifice go down with the ship (to mix up an analogy or five).
I yam quite tradition-minded myself (see works of Micheal Oakeshott for what this "tradition" word means to me) as long as the tradition is dynamic and not entirely contained in one fusty ole book written by A Loon esq in 1804 whilst wandering dehydrated in a desert or sitting in his cave barking like a dog...........
Or making furniture rather well but in a lonely shop divorced from the knowledge of other makers of good furniture, as well as the events of the future, which knowledge (shock, blither) might be just as coherent and of practical utility as his own.
Here is a little sample of Prof Oakeshott with some Popper in it too! (Bliss).
http://www.michael-oakeshott-association.com/pdfs/mo_letters_popper.pdf
*****
But now I must deal with that Ray Pine who is making a spurious analogy, concerning sandpaper and skissors, to our plane experimentals. Hopefully he does not make such free analogies when deciding on the merits of actions by, lets say, purple-skinned lizardmen from Planet Pondle. Just because one purple-skinned fellows once ate a human alive doesn't mean they are all like that. In fact, I once met one (it was a dark night out on the Lune estuary) who gave me one of his sandwiches and his coat, as I was shivering (with fear, in fact, not the cold). Of course, I don't know what was in the sandwich or what that coat was made of. It dissolved away as soon as I got home and switched on the light.
But I don't recal mentioning sandpaper or any sharpening tekneek using a pair of blades rubbed together over it. Cuh!
Lataxe, whose mind is made of RAM not ROM.
RAM not ROM nice one
>blither<
http://flag.blackened.net/dinsdale/dna/book5.html
See third chapter second paragraph
some where along the lines of "cross-eyed badger spit".
>angel boots<
most of the angels I am familiar with go bare footed when on the head of a pin. Bad angel, bad ! Going bare footed like that. Zoot was one name that comes to mind. At least I think they were angels. That was what they said they were. Well at least they were barefooted I recall that clearly. Memory is not what it once was. Here is some footage from that vacation/adventure so you can judge the facts for your self.
: )
http://www.youtube.com/watch?v=QvRH-8eF6l0
Roc,
"There really needs to
Roc,
"There really needs to be a page for quotes and one liners. "
Yup. That would be priceless. To come up with zingers really takes intelligence, and there are some VERY smart prople around here.
Sometimes I think that the smarter the person, the shorter their posts. But then I read the posts by you, Lataxe and me, and I know my hypothesis must be wrong. :-)
Someone needs to write a book. "The Incisive Wit of the Knotheads".
Mel
Short posts
>Sometimes I think that the smarter the person, the shorter their posts. <
Well you know how I feel about short posts
http://www.youtube.com/watch?v=KyabGc6izXo&feature=related
I give short how tos if I am sure the person can not possibly understand the long version. In fact I am the master of the short how to. For example:
Q: How did you do that?
A: I f***ed with it 'till it worked.
Kind of boring huh. Not worth the effort to read huh. Well I suppose that could be said for other of my posts. At least they keep you busy until it is dinner time. Shoveling around.
The secret to mastering life.
Roc,
I believe that you have encasulated the secret to life in a single sentence.
"I f***ed with it 'till it worked."
Some people believe in "managing". I have seen "managment". I have even done it. But when seen from a bird's eye view, is often looks like "muddling".
I believe a wood-hacker becomes a wood-worker when he realizes that he can get himself out of anything he gets himself into. he has the can-do attitude based on real experience and cabapility, not on BS. Which is another way of saying that a good woodworker is a person who can say "I f***ed with it 'till it worked."
I hope you know that I said in my last post to you, .that I gave up on the idea of "the shorter the post, the smarter the guy" because of folks like you and Lataxe.
It was Einstine himself who said, "An explanation should be as short as possible, but no shorter."
And as I remember, he was a smart guy.
Enjoy,
Mel
PS I doubt we will see many threads as long as this one in the coming months here on Knots. After a while, it gets time consuming to find the post that you have been notified that you got. THis is not a complaint, just an observation. Complaining doesn't get me anywhere.
Notified ? Oh that hasn't happened for a long time.
>it gets time consuming to find the post that you have been notified that you got<
I go click the cute little boxes but nadda. Nope . . . I do it the old fashioned way; I come here with my gloves and my entrenching implement and shovel around.
I have even been known to find a pony now and then.
PS: I get notices every day from the Apple computers chat room. Funny that. Not complaining though.
Noooooooooooo
Roc,
I generally RTFM rather FWITIW as then one may rely on other fellows having already done the FWI and writing all about it in the FM so that one may move directly to the IW part. When younger and hormonally inclined to FWI I often found that it FWMe instead, as my scars will prove!
Now, there is that matter raised by David Pye concerning the process of pushing the envelope so that educative errors occur. However, when pushing there is usually the hope that the thing stretches rather than breaks. There is also the matter of equal and opposite reactions. Still, who would want to lose all sense of adventure?
However, it helps to recognise envelope edges, which requires intimate famliarity with the envelope and its parameters as a whole. Going at one cack-handed and higgerant will only result in rips and tears, with no envelope left really.
*****
I yam imagining a certain sharpening class.
"How shall we best sharpen this chisel, Mr Kleverklog Your Worship"?
"Well, just FWITIW using gubbins selected at random and at great cost. The bandages are over there".
And in another location there are cries of dismay and repentance, as fellows not following the "1907 methods with planes by A Cantanker, aged 87", or even glancing askance at the Brent Beach website, are marched off to The Heretics Punishment Room where they must scrub planks flat with a large set of hollows and rounds sharpened only with a 50 grit oilstone.
***
Meanwhile I must go to shovel more manure. The ladywife has acquired a Very Large Heap of ex-mushroom growing compost (straw, rotted horsey stuff and lime). There are no ponies underneath (I hope) but there may be some rhubarb and strawberries down there in need of sunshine....... I may have found my troo vocation, shovelling [that word is not allowed amongst delicate folk - the Knots Nanny].
Lataxe, pitchfork in hand, oh-arrr!
Mushrooooom Shovel Bevel Angle....
Lataxe, Do you have a sharpening guide line for Mushroom shovels? Any particular one work better than another? Or as in my case, I see if I can dodge and stay out on the bike long enough to miss the FUN!
Great posts, got out to the shop and got motivated to sharpen today. Really when you get down to it, that spot of being a touch lazy and not sharpening soon enough, will create more problems than anything. Always seem to be just one more pass, one more cut before I sharpen. Just keep it sharp seems to work for me. 7 Planes, 9 chisels in an hour.
Morgan
Morgan,
I am filled with dismay at the very idea of anyone using a shovel to move mushroom compost as this practice was made illegal in 1581 by the then Lord Chancellor. The pitchfork is specified, which has a number of advantages:
* It is easy to sharpen as one simply plunges it repeatedly into a handy peasant; the iron in his blood reinforces the metal. Also, this practice keeps the others quiet as one taxes their corn and barley.
* There is less chance of important heap-worms being cut in two. Heap worms are a very necessary part of heap-breakdown, as only they are prepared to chomp the stuff to a condition fit for growing strawberries, curly kale and manglewurzel.
* A pitchfork weighs less than a shovel. This matters as one becomes more and more of a feeble ole scrote. It is easier to wave dangerously about as one grumbles about youth and its tedious activities.
* When used as a throw-spear, a pitchfork moves more predictably to its target, as there is less deflection from side-winds and shovel blade lift. Thus one is more successful in dealing with those who have attempted apple or plum-scrump from one's orchard, as they attempt to run off from legitimate justice.
* When in possesion of a pitchfork one may utter the expletive "Oh, arrrr!" to every enquiry, whilst a shovel-holder must use great strings of incomprehensible and difficult-to-pronounce Blarney, since the shovel is the emblem of Irish Navigators everywhere whilst the pitchfork represents Cloddhopper of Norfolk, a simpler being.
* A pitchfork looks much better with my dungarees, straw hat and bare feet. Would Cleetus be seen with anything else?
Lataxe, a country bumpkin.
PS What do you call a Navigator with a shovel in his head? Doug. And one lacking the scalpy implement? Douglas.
Lord Chancellor was a smart fella
Lataxe,
I am quite sure i disagree with the Lard Chance'es decree that no shovel shall touch the mushroom compost. Not sure why he wanted to muck about with the compost himself, and to decide how others should muck about with it,. It is certain that he was a Champion Mucker About though to have passed such a decree. In the end it does explain what happened around 1776.... when some yank decided to use a shovel, since it was all he had in hand. Yep, pretty shure it was the Boston Mushroom Compost Party that was the proverbial straw that broke Colonists back... Don't be passing decrees on how to use a tool, Don't tread on me, was flown with a pitchfork instead of a snake on the flag. History may have gotten that bit wrong.
Now a Pitch Fork is what the Willagers used to come after Frankenstein to rid the neighborhood of unruly and unwelcome guests. It is now used in urban areas by young children on their way for tricks and treats as a Halloween Costume. Under no circumstances should a regular fella be coought with one in hand attempting to damage his ol' painful and broken back. The missus, rightly standing on top of the heap, should have all the priviledges and honor of moving the pile to the proper locations. The chap, or the Mr. in the equation,should be at the pub, pondifercatering on the pile, and should honor Morgans decree of 2010.
All good men unite, and do not muck about! They should be gallavantering round the countryside on the Bicycle enjoying their formative years.
Morgan, a man who despises mucking about immensely.
Lataxe,
I tried to edit/add to my last post, but do not see an 'edit' button (anymore).
When I came home from work, I could not resist 'dragback' idea. I tried it on with two block planes (9 1/2), one LN with A2 iron, the other Stanley with the original iron (I did not want to start with a replacement hock iron). Stock: 9" long, 1" thick maple board (worked on the edge). Both irons were due for some stropping, Stanley sooner than LN. I started with Stanley: few backdrag strokes on a green strop. I expected that a strop would give me a zero-clearance microbevel faster than wood (impatience might not be a virtue but could yield faster results - better with wood than with people). Then I tried it on the board. I took a few swipes before to compare for a change in sharpness. I felt bad for LN, so I gave it the same treatment (no, I do not take my planes to the garage - I do not have a shed - to put them to strop...). I also took a few swipes on the 'original' board.
Since the process is so easy (at least for some folks) to reproduce, I won't report any results such as the quality of the surface. The microedges were tiny, but easily visible (even more so under a magnifying glass). Regular stropping will have to wait a while longer. Either I am too lazy or the edges are 'different'.
Take care,
Metod
drag the plane backwards
I have a great deal of experience doing that. I drag my scrub plane back because I am going like a sewing machine or "like a bunny" so I don't lift OR twist the plane back on the outer side edge like Frank Klausz recommends for normal/finish planing. Meaning a less cambered blade and with the grain.
Lifting a scrub plane just slows down the thicknessing too much and I can "get away with" not lifting. No doubt in the planing you are doing with the grain there is some edge sharpening that goes on but the clearance is lost and clearance is important to DEPTH of cut with the grain.
Let me say this about that. You say your blades stay sharp for a good long time even not doing the drag. The purple heart and bubinga ( to a lesser degree) just eat blades. So I got in a lot of experimenting with slight changes with this blade geometry thing.
BUT
I was merely observing and verifying what I had already read in the many great articles hear in FWW and a few others.
So it was more of a "Yep" experience rather than "Oh look what I discovered".
My scrubbing is either across the grain or diagonal depending on what causes less trashing of the surface and still takes the thickness and lumps down. Cross grain is the key here. With the grain is a whole different animal. Cutting purple heart with the grain the blade MUST be truly sharp and have some clearance or else skatey skate.
I get along with the dragging for this scrubbing but not with a large radiused /with the grain blade.
Pronounced radius and across the grain requires a blade that is only moderately sharp but can keep it cutting because there is not much width actually in the wood and across the grain the fibers are pulled up easier than with the grain which is kind of like smoothing the fibers down like flattening a rooster tail. Wider large radius blades tends to quit cutting and rise up and slide over the surface. Too much edge area for the amount of ballast and triceps that I have. See first posts.
And around I go.
Roc,
I confess to not being all that convinced that dragging-back might make a wear bevel that usefully sharpens rather than dulls the edge (as the wear bevel formed when pushing forward inevitably dulls it, as demonstrated convincingly by Mr Beach, no matter what Larry the ole wife scowls).
A mental experiment might go like this:
Replace the plank being planed with a flat sharpening surface such as a large diamond plate of 8000grit. Drag a plane backwards over it with the blade projecting as it would for a fine cut.
This is like amplifying the sharpening effect of a dragback on wood only, by a large factor.
* In no time there will be a back bevel on the blade with a zero clearance angle.
* The blade will be continuously sharpened.
* The blade projection (and hence cutting depth) will decrease.
As soon as this zero-clearance back bevel aquires a surface area too great to allow the plane user to push the balde edge below the timber surface, the plane will begin to skate over that wood, should one attempt to plane it. This area will always be small; very small when the timber is very dense, such as purpleheart.
Thus a dragback sharpen is actually counterproductive as it will always form a zero-clearance back bevel and quickly prevent the blade edge biting.
Except that any dragback bevel that sharpens the edge but increases the wear bevel by only a tiny amount will be useful until and unless that back bevel gets so large (it will still be very small in absolute terms) that it prevents the blade edge biting.
******
Suppose we take Metod's approach and make a near-zero back bevel of tiny area. Depending on the degree of clearance angle remaining, the blade edge may or may not bite. The same parameters apply - larger back-bevel area, lower clearance angle and harder timber prevent planing action sooner.
In addition, the wear bevel still forms from forward-planing (as well as from dragback, if one doesn't lift the plane), Because the initial clearance angle is very small, the wear bevel will form a wider area more rapidly, thus preventing edge-digin sooner; planing soon becomes skating.
*****
Contrast this with a ruler-trick back bevel, which barely decreases the clearance angle. It merely ensures that:
* it is easy to form a polished surface on the non-bevel side of the blade, where one has a roughish-backed blade;
* it gets rid of any blunt-causing wear-bevel inevitably caused by normal planing action in any blade.
(Incidentally, this ruler-trick back bevel is therefore only of use when either the blade back is not itself easily polished/flattened and/or normal sharpening of the bevel-side does not also take off the wear bevel on the other side of the edge).
*****
SO, a mental experiemt suggests that the plane and sharpening experts such as Mr Lee and Mr Beach (even Mr Williams) are right to eschew a zero-clearance back bevel or anything like it.
Not to say that mental experiments are not best confirmed by real experimentation, should one doubt any of the assumptions of the mental one. However, such experiments are worthless unless all the parameters are known and controlled, as who knows what accidental configuration may result in an improved shaving yet be attributed to the factor one wishes emotionally to be the relevant one?
***
Thomas Kuhn and The Structure of Scientific Revolutions..........
An enlightening book, especially if one considers the Big Revolutions such as Einstein amending Newton, the death of determinism brought on by Benoit Mandelbrot with his Chaos and the major realisations about the intricate meshing of all planetary life illuminated by James Lovelock and his macro-ecology models.
However, as a counterpoint (not a contradiction) it is as well to read also Karl Popper's "The Logic of Scientific Discovery" as well as "Conjectures and Refutations".
Thomas Kuhn is at bottom a sociologist and a historian. His studies and conjectures provide a meaningful understanding of the role of human nature in scientific endeavours. But thay are conjectures, as with all history. Some post-modernist kreetures and other New Age klaptrappers have unfortunately used some of his concepts entirely out of context to justify the notion that, "One theory is just as good as another" and "All facts are mere interpretations from this or that (equally valid, no matter how obtuse) theoretical standpoint".
This is not what Kuhn is saying, although I suspect Mel wishes it was.
Karl Popper underlines most persuasively the fact that science is always self-critical and has what Kuhn calls "revolutions" built-in as part of its entirely evolutionary structure. Paradigms do change "seismically" but they tend not so much to overthrow previous ideas as expand and correct them. They reconfigure the scientific landscape with some structural damage; but they are not a catacysm or armageddon.
As you noted in your posts, only a bloke content to drive a car backwards at 25mph and claim he invented driving will believe the "revolution" concept.
Lataxe, who can often find a use for old bathwater, besides retaining the babes.
Sharpening (or honing, or stropping) a blade by pushing or dragging it across a surface while it's in the plane seems akin to "sharpening" a pair of scissors by cutting sandpaper with them.
I'm reminded of the concept racecar engine that had rubber camshafts. As the engine revved to higher and higher rpm's, the rubber would hyothetically melt, giving a wilder and wilder profile. ZOOM!
And yet there used to be a commonly accepted practice of freshening jointer knives by dropping the outfeed table, and passing a whetstone across the running cutterhead. Never tried it mesel' , being one of them whatever it was you called folks resisting any kind of change. I like my jointer blades DULL!
Ray
If we can agree as to terms.
Lataxe,
You and I are on the same page and agree I think basically down the line. Sounds like you may be talking bevel up blade in your example(s). My scrub is bevel down (I think safe to say as are all scrubs ) and I was continuing (in my mind) with a bevel down with my other , with the grain, planing reference. Keeps Larry happier too no doubt .
back bevel
to be clear for the people attempting to make sense out of our discussion I would say Lataxe means a micro bevel in terms for a bevel down blade. I totally understand what you are meaning but others may have their head swimming. A back bevel would be on the flat side of the blade ( upper most side ) a micro bevel would be a bevel ( small thin facet ) added to the major bevel ground on the under side of the bevel down blade.
If a bevel up blade then I suppose the facet added to the flat side of the blade , which is down for a bevel up blade, would then be a back bevel.
(to add even more verbage , to be literal , really a back bevel is a kind of micro bevel but since the back bevel is the only bevel on the flat side it IS the bevel there as compared to the secondary bevel on the main bevel side which is a small, micro, bevel in comparison to the main bevel.)
[ I could not get through typing that without pausing to laugh. Sheesh what a mess ]
New people : sorry that is the best I can do. Feel free to now tear your hair out and blither. It gets easier once you start using all these different blade configurations. Really it is all the same effective blade cutting faces, flat or bevel, just with a different plane wrapped around the blade that may be easier to work with for one reason and another. There is no do all plane though I would brave the wrath of the faithful and say the bevel up gives that one a run for the prize. There are draw backs to that design too but in my view minor.
OK
Sorry Lataxe for being so wordy. Did you fall asleep soon after I began to bleat on and on ? Don't answer that. There's a nice fellow.
I must say your text was quite clear otherwise. I find my self getting lazy and muddled with my posts these days.
>all the parameters are known and controlled<
Aaaaah a jig. That is why I am so helplessly in love with a sharpening jig. A Veritas mark II please with the bevel setting plate. To be clear for the readers these two things
http://www.highlandwoodworking.com/veritasmkiihoningguide.aspx
>counterpoint . . . read also Karl Popper's "The Logic of Scientific Discovery" as well as "Conjectures and Refutations". <
>conjectures, as with all history< Henry Ford wasn't so kind. He called most history "bunk". One year he was riding his bicycle to work and begging for money to get his ideas into practice. A decade or so later he was building Fair Lane, his mansion on the Rouge River in Dearborn
http://en.wikipedia.org/wiki/File:HenryFordEstateSWSide.jpg
had heated toilet seats and floors you know. Must have had a pretty good perspective on things in general.
: )
Bit confused about the Jews but we won't go there.
Thanks, I added it to my list of new books to get when I get the iPad. It is like I am a kid and Christmas isn't for another three weeks !
: (
>science is always self-critical <
aaahh and that is a beautiful thing. There is at least one other general system of living I wished would adopt that. One only has but to read "the daily frightener" to see what happens when that other system fails to be self-critical. I can't help but take it over the top and say perhaps that other system might do worse than to close up shop and take up gardening.
PS: do you suppose there ARE any new people reading this ? Or is it just the four or five of us just going on . . .
PPS: does me heart good to read your writin'
New people . . . are you there ? Do you care ? Are you there . . . does this help ? Are you there . . .
Mel, I don't know of a good book especially when dealing with traditional bed angles. Most of the stuff I see completely loses sight of the fact that you're preparing stock for joinery and a uniform predetermined thickness is the ultimate necessary goal. The Cosman and Schwarz videos are good examples of this, both start out by just whacking away at the wood with a scrub plane and no discussion of starting out by planning to end up at any particular point. Most real work will start out with 4/4 rough stock and hand work usually has a finish thickness of 7/8". A couple misplaced scrub plane strokes can either generate scrap or have you redesigning all your joinery and planing an extra 1/8" off all the stock for a suddenly anemic looking project. So when you see someone like Deneb demonstrating in public you need to understand that what they're doing is completely out of context and pretty meaningless. The stock they're working on is intended to "wow" the obsurvers and will never be used for anything else.
I don't get to do this stuff any more. My days center around other things. If I did prepare some stock by hand I'd use a trying plane with a very slightly cambered iron. The reason for this is that Don does use the shop trying plane when making planes and he's the one that sharpens and maintains the trying plane. If I sharpened the plane, it would have a straight iron with the corners softened at a very slight angle. These are actually so close I doubt anyone would see the difference if two irons were set side-by-side. Don likes the slight camber because he feels it's easier and quicker to square an edge when the camber allows him to control where the thicker part of the shaving is removed.
Larry,
As always, your response makes a lot of sense, and it is directly relevant to my current situation. I just bought a nicely figured birds eye maple board, that was rough planed to 4/4. It has a bunch of deep tearout. I was wondering how to attack this with handplanes without losing more than 1/8". Using a scrub, as you said, would not be good.
I am going to start by using my New York Plane Co try plane. It is sharpened straight across as it was when I got it. I will try to take a scant shaving.
Luckily, as a retiree, I am only in a hurry to learn, and not to turn out a piece in a given time. I will experiment with a few other planes with different amounts of camber. but not with my scrub.
I really do appreciate the time you take to answer my questions.
By the way, i haven't seen the other toolmakers here on Knots lately. Mike W, Ron B, Phillip M., .. Over the years, I have gotten some great info from Mike and Phillip. I don't know Ron very well.
I will write to you in a while, after I tackle the birds eye board with the bad tearout.
Enjoy,
Mel
Be careful here dear
>it went over every respondent's head <
You would first need to know what is , or is not , inside the said respondent's head. Then you would have to put that and the other suggestions into practice.
Often tear out occurs ahead of the blade not behind the cutting edge so those who "know" just disregarded your hypothesis. Why contradict every little nit. Best to move on to the shortest answer. Mel likes those.
Tear out often occurs when the blade encounters reversed grain and or weakly bonded fibers. One is planing on "with the grain", like smoothing the hair down on a short haired dog, then moves into a patch where the fibers are angling up like going against the fur on a short haired dog's back. The fibers climb the top of the blade, pull the blade down into the wood causing a chip that is too thick to break and curl as it should and "pop" a small hunk of wood comes out of the surface.
AGAIN :
Your low clearance helped the blade ride high and jam the fibers and clip them off before they could climb the blade. A back bevel will do the same thing and is a better solution. Reread previous posts as to why better.
Roc,
I knew that tearout is likely to happen when planing against the grain, but did not have my own 'explanation' or knew of somebody else's as of why it happens. If your explanation
"The fibers climb the top of the blade, pull the blade down into the wood causing a chip that is too thick to break and curl as it should and "pop" a small hunk of wood comes out of the surface."
is correct (just because I too believe it to be correct <g>...), then a near-zero clearance angle (according to your snow shovel analogy) would be preventing the blade to be pulled down and therefore eliminate/reduce the tearout. Sure makes sense to me. Time to convert to new 'belief'.
I really appreciate your 'patience' with me as well as your insights.
Take care,
Metod
To be clear and not to offend
>would be preventing the blade to be pulled down and therefore eliminate/reduce the tearout. Sure makes sense to me. <
The snow shovel thing is NOT a good idea though. With a freely held carving chisel yes but not a hand plane. The near zero clearance is not a good configuration to use generally. Only as an absolute last resort ( which I have never run into yet ).
I am thinking the shallow clearance limits thickness of cut, control of the cut and over burnishes the wood. The back bevel making effectively a steeply angled blade will push those fibers "back into their hole", down along their axis and keep them there while being sheered off. The curl of wood can even be crenelated rather than a smoothish wisp/curl. See Veritas tools blades diagram for steep bevel up blade. Even though you may use a bevel down and a back bevel.
> Time to convert to new 'belief'.<
I am probably misunderstanding what you are telling me. Mercury in retrograde messing with communications. The change of belief would be to adopt or at least try a go with a normal clearance of more than ten degrees, maybe twenty or so and then put a bevel on the flat side ( up side ) of your bevel down blade. Keep increasing it until the tearout is eliminated.
May be on the order of a ten to twenty degree back bevel on your 50° bedded plane blade. The advantage is then you can cut the wood down bellow existing tearout more quickly because you can take heavier cuts than the one or two degree clearance set up and the sharp edge will last longer. Probably much longer.
With some of the funny scraper planes that you mentioned. Well you mentioned scrapers and I am throwing in my experience with scraper planes is that just about the time I get the surface done a stroke chatters. More a result of a very wide blade that gets too dull on me but I think when the low clearance blade gets dull , say when doing a larger surface you will get skating which goes right along with chatter and then you got to back track.
Try the 50° with 20° clearance and 10° or more back bevel on a significantly large surface like a cabinet top and then your originally posted configuration over the same area and let us know.
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