So I am flattening a new chisel.
I take it first to a coarse diamond “stone”. Scratch pattern looks consistent. Move to 1k grit.
Scratch pattern looks consistent. Move to 2k grit (perhaps overkill.)
Scratch pattern looks consistent. Move to 4k.
Lots and lots of lapping. Around the edges, starting to get nice and shiny. The middle, well, that’s not being touched-still looks like it did off the 2k grit.
My assumption is that the back is not truly flat yet and I have to drop back to 1k or even the coarse diamond. My thinking is that if the back is flat, I should see even wear off the 4k, not just around the edges. Am I off base?
Most nights are crystal clear, but tonight it’s like he’s stuck between stations.
Replies
I think what you're doing is rounding the back, ever so slightly, on the fine stone. I find that it's easy to do that, especially by taking short, quick, back-and-forth strokes. The way to avoid it is by taking long, even strokes the full length of the stone; it's when you're reversing direction that you have to be the most careful.
-Steve
You just described my technique exactly. So you're saying it's more of a slow one direction-pause-slow the other way as opposed to the herky-jerky?
I've never really had this problem before, but then I'm not exactly a whiz at this either.
Thanks.
Most nights are crystal clear, but tonight it's like he's stuck between stations.
"So you're saying it's more of a slow one direction-pause-slow the other way as opposed to the herky-jerky?"
That's what works for me. Your mileage may vary....
-Steve
I routinely see this when flattening backs. I'll be shrinking a low spot at a corner for example, and then the coarse stone seems to have reached the entire surface. However, if I move to finer stones right away, the low spot shows up again. I always figured that the coarse grit sits enough higher (between peaks) that it can scrape the low spots enough to look as though they've been addressed, but a move to finer grits reveals that it was just the peaks reaching the low spot and not an indication of true flatness. Just back up to the coarse for a bit, and all should be well.
To the extent we're talking about back flattening's finer points:
- I find that the more I am making a motion parallel with the long sides of the blade, the better my chances of getting the blade flat and the less risk of rounding or skewing type mistakes - especially for narrower chisels (wide chisels and plane blades are sort of self jigging against rounding over - so to speak)
- Keep your stones flat - especially at the higher grits or you are destined for frustration
- At lower - more coarse - grits makes suse to work as much of the back as possible especially if you are needing to remove a significant amount of material - otherwise, you back can pivot on the ledge or belly that you instroduce where the portion of the back you are working meets the part you have not touched. On later stones (and in paring operations and such later on) this belly can cause problems.
All good points everyone. It's a 1" chisel, so I don't think I'm rounding too much on the back-and-forth, but it makes sense so I'll slow it down. Samson, I do what you mention also-I try not to keep the chisel or blae perpendicular to the stone; I angle it as I think you are talking about.
I usually flatten about 2" of a chisel. That may be too much, but I want to do it once.
These are all-new stones I am using. I got tired of some stone, some sandpaper, so I got the DMT DuoSharp and a couple of new Shaptons, and I have been probably over-flattening them. Maybe I've been watching Harrelson Stanley too much.
Most nights are crystal clear, but tonight it's like he's stuck between stations.
Edited 11/8/2007 11:31 am ET by JJV
>- Keep your stones flatHow do you go about flattening an oil stone? I've seen lots of tools sold for flattening water stones, but not oil.
George Patterson
Please excuse the intrusion...
It largely depends on the composition of the stone.
It helps a great deal if you have two similar stones.Aluminum Oxide compositions can be "flattened" by using
silicon carbide as the abrasive medium. Fix one stone
and use a bit of kerosene for a suspension medium.
sprinkle some silicon carbide abrasive on the stone.
(90 grit is good to start). Rub them together. The moving stone should go about 1/3 its length
past the fixed stone. The fixed stone will acquire
a hollow. The moving stone will acquire a belly.Switch positions, rinse and repeat and you will work your
way to "pretty good". I use "brake cleaner" for rinsing. This works for novuculite stones as well, a bit slowly
for my tastes. The good part is that you can get a very useful
stone from a decidedly inferior product.The other interesting bit is you can alter the "coarseness"
of the stone ( albeit within a limited range for a limited time )
by where you stop with respect to the grain size of abrasive.Here you are making use of the tendency for the abrasive to
fracture as it rolls around between your targets. As the
powder "fractures" it in turn makes smaller fractures in
the target stone. So if you get to "flat enough" you can
freshen the 90 grit powder, go a few minutes more and get a fast cutting stone. Go a few minutes more and get a stone that cuts
a finer scratch.This is especially useful for coarse silicon carbide stones that
have been in use for a while. These stones fracture their
grains in use but they are tightly held by their bonding
matrix. In use they become smooth and cut ever more finely.The "rub" with the abrasive particulate is effective in
coarsening the stone and restoring its metal removal rate.Sorry for the intrusion.Hope this is usefulAl
Thanks, but I think that won't help in my case. The stone I want to flatten is an old, large carborundum stone. If I could find one as large, I would just replace it, but I can't really get another to work it against.George Patterson
carborundum (silicon carbide) can be easily worked
with siicon carbide sandpaper (wet or dry).
You can then "tune" the roughness with silicon
carbide grit ( lapidiary shop or automotive paint shop )
and a piece of glass.If the stone is bellied that is, thick in the middle
silicon carbide stones in 2 x 8 inches are only a couple
of bucks.
Thanks; I'll try that.This one is about 2.5" by 12". I bought it from Allcraft in 1973. I've been looking for another that size for about 15 years now and can't find one. I'd sure rather buy one than flatten this one.
George Patterson
Johnnie,
You are right on.
If the back is not equally scratched over the part that you want flat, you still have work to do. Use the coarse diamond stone that you are talking about. Then go to the fine, and to the extra fine. I end up with the extra fine Spyderco ceramic stone which gives a mirror shine, much better than the extra fine diamond stone. I get good results from a sequence of diamond stones followed by the Spyderco ceramic stone.
The first stone will take the longest since it will do the flattening, ie, it will give you a uniform scratch pattern, which means that you have to get rid of any thing which is high or low. The next stones go very quickly since the chisel back is already flat, and you are just getting a shinier surface with each finer grit.
With chisels and plane blades, you only have to flatten the bottom half inch or so.
Hope that helps.
Enjoy,
Mel
Measure your output in smiles per board foot.
It does help. See, these are things I once knew, but it's been so long since I did anything like this I've kind of forgotten.
Back to the Duosharp it is. And it's kind of funny to think-these chisels are sold as being "ground dead flat". Perhaps they are, but done so before the steel is fully settled.
Most nights are crystal clear, but tonight it's like he's stuck between stations.
With chisels and plane blades, you only have to flatten the bottom half inch or so.
I disagree. You should keep the entire back FLAT (especially on chisels). I would agree if you had said "polish" instead of flatten; only the area near the tip needs the attention from the fine grits, but at coarse grits, espcially where a good deal is being removed, address as much of the back as possible. See diagram:
Big Guy,
you said: "You should keep the entire back FLAT (especially on chisels). I would agree if you had said "polish" instead of flatten;"I agree. I was writing fast and was trying not to be too wordy. As Einstein said "An explanation should be as simple as possible, but no simpler." I failed to heed the teachings of the Master.
Mea culpa.I work the entire blade back on the coarse stone, and only polish the bottom part. If I can get more than an inch easily, I do that. If it takes too much time to get an inch, I just polish a half inch or so.
MelMeasure your output in smiles per board foot.
Mel,
I think Samsons point was that you need the area flat where it will contact wood when paring: please correct me if I'm wrong Samson.
I think it's a matter of preference as both methods have been shown to work. To me it's the same thing as just flattening the sweet spots on the sole of a plane or the whole thing. My preference is to flatten all, both planes and chisels and I polish them all too. It's not that much more work once it's flattened and you only need to do it once.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
"you need the area flat where it will contact wood when paring"
Yeah, that is true ... but my point was that if you only ever put the last 1/2" of the chisel on the stones to flatten the back, you may well raise that last half inch section relative to the rest of the back - see my diagram in the post to Mel above. This would be a problem when you went to flatten on the next stone if you strayed from that 1/2" - i.e., put 3/4" on the stone. It would also be a problem in a paring operation like this:
Edited 11/8/2007 4:35 pm ET by Samson
Without going through all the preceding posts (I have read several), I offer the following words of wisdom :>)
The back needs to be flat generally for purposes of registration. This means that the edge of the bevel needs to be co-planar ... in line .... with the highest point on the back that will be pressed against a fence. So no bumps, lumps, or backbevels. A hollow is fine.
The back does not need to be flat across the width of the chisel, just across the width of the back of the bevel face. There needs to be enough flat across the back of the blade to provide secure registration.
The back of the bevel face also needs to be honed as smooth as the bevel face, per se. The edge is only as sharp as the lowest grit used on one side.
To get the back flat at the bevel face, keep grinding until you feel a burr developing across the entire width of the face. Do not proceed until this occurs, do not pass Go ...
This article I wrote may interest some:
http://www.wkfinetools.com/contrib/dCohen/z_art/lappingBlade/lappBlade1.asp
One change I have made from that article is to now use beltsander belts glued to glass as the initial lapping medium.
View Image
When contact glued (I use a weak poster spray contact glue for ease of removal), it can be seen that you get a flat surface.
Use short side strokes to maximise control. Avoid long strongs as these will tend to round up.
Regards from Perth
Derek
Derek,
Great post, as always. Why do you persist in using sandpaper?
Why not switch to diamond stones?
Sandpaper is cheap to start off, but gets very expensive.
I use the DMT extra coarse and coarse to get started on the backs of plane blades and chisels, and then work down to extra fine, and end up with a Spyderco extra fine ceramic stone. The results work for me.There is that lingering question of whether diamond stones will hold up for a long time. Mine get used a few times a week. At the Woodcraft store I work at, we have a set in the shop that gets used by a number of folks daily, and the set works just fine, even though it doesn't get the care that mine does (always use water, and always wash and dry them and then air dry them). By the way, the amount of time I spend on the backs of chisels and plane blades has been greatly reduced as I moved from used Stanleys, etc to LNs, which I get with my discount at Woodcraft. They are in much better shape then the old Stanleys when I open them up. :-)So why don't you use diamondstones for flattening?Measure your output in smiles per board foot.
Why do you persist in using sandpaper?Why not switch to diamond stones?
Hi Mel
One reason is that I have a bunch of old belts that I bought to use with a stationary belt sander that has since been replaced with a larger model. So they are cheaper than a diamond stone.
Another reason is that the grits go down lower than any diamond stone available. I do have a 10" DMT Duo Coarse/Extra Coarse, and the lower grit is only 220. For some blades, where a lot of steel needs to be removed, I might start at 80 or 120 grit.
Yet another reason is that the longer length of the belt-on-glass over a short diamond stone is that I can grind more at a time. Again this makes for faster work, which is important at the lower end of the grit range. Higher grits take progressively less time to remove scratches once the steel is flat.
This business of diamond not holding up is open to debate. On the one hand Larry Williams and Steve Knight both state that they have worn out diamond stones on steel and now only reserve it for their oil and waterstones, respectively. I listened and bought mine to flatten my Shaptons. At the same time, I have used the same Extra Fine diamond stone for about 10 years. It looks bald but is still going strong. I believe that Philip has also used the same diamond stones for some years. Don't confuse the initial loss of bite when a new diamond stone wears in. I think what is happening is that the stone is just being levelled out.
When I wrote that article it represented the materials I had to use at the time. It remains as a guideline for those unsure what can be done. It does not mean that I only use this media. I will happily use the belts, then diamonds, and then Shaptons (I go to 12000 and then strops for edges).
Regards from Perth
Derek
Derek,
Thanks for the explanation. But I'd like to take it a step further into "my unknown". What about cryo treated blades? Is there a difference in the media (sandpaper, diamondstones, waterstones, etc) that you use to sharpen and hone cryo treated blades? Are they likely to wear the diamondstones even faster? Do they respond to diamondstones differently? eg do you have to start with a coarser grit? I understand that it takes longer to sharpen and hone a cryo treated blade, but I wonder if it affects the decision as to which media to use.Also,I have been using a flat grind, but that requires more work to hone than a hollow grind (except if you are using a secondary bevel). So a second question is: do cryo treaded blades cause one to opt for a hollow grind? I suppose that wif one has a linisher, one doesn't ask such questions :-)Any advice on these two questions would be appreciated.
Thanks,
MelMeasure your output in smiles per board foot.
What about cryo treated blades?Is there a difference in the media (sandpaper, diamondstones, waterstones, etc) that you use to sharpen and hone cryo treated blades? Are they likely to wear the diamondstones even faster? Do they respond to diamondstones differently? eg do you have to start with a coarser grit? I understand that it takes longer to sharpen and hone a cryo treated blade, but I wonder if it affects the decision as to which media to use.
Good grief Mel! I haven't the foggiest idea.
Also,I have been using a flat grind, but that requires more work to hone than a hollow grind (except if you are using a secondary bevel). So a second question is: do cryo treaded blades cause one to opt for a hollow grind? I suppose that wif one has a linisher, one doesn't ask such questions :-)
I grind a hollow on all Western chisels (except mortice chisels, which have a microbevel on a flat grind) and all bevel down plane blades. This makes it easy to freehand on Shaptons. To date I have used a 6" high speed bench grinder but I have just acquired a Tormek 2006, and so will use this now. Japanese chisels and BU blades are flat ground on a belt sander, and the latter then get a microbevel with the aid of a Veritas honing guide.
The only reason that a Japanese blade is flat ground is because most of its face is laminated soft steel. Otherwise my preference is a microbevel for all blades. This is the fastest means to a sharp edge.
Regards from Perth
Derek
Gald to see you use a magnet to hold the chhisel. I thought I was the only one that thought of this.
Sure makes the job easier.
If the middle isn't polished, then it is hollow! Many of us pay extra for Japanese chisels with hollows!
Flattening and sharpening come with experience. You takes your licks and try dis and dat and one of these days you'll have figured how to hold your tongue just right and you know how to sharpen.
For flattening, I use either a granite plate or my table saw top with SC paper. I work up through the grits starting with 220 unless the blade or chisel was really abused and then its a lower grit. Flattening only occurs once so take your time and don't skip any steps and you'll get it. Also, I believe it helps if you take a bit of carpet tape and secure a block of wood on the bevel side to help give consistent pressure on the blade or chisel.
I'm thinking that 4k stone is out of flat. That would explain why you are getting the edges polished and not the center.
The more I work wood, the more I find that perfectly flat backs is an unecessary waste of my time. Registration for example, is a red herring. Chisels don't really work that way. You're better off paring bevel down. If you insist on paring flat side down, you'd be better off with a rounded back side like a carving tool.
I can't tell you how many dovetail pins I've split doing exactly what Samson showed. You really need to come at those from the other direction (where no registration is possible).
Flat backs have become a modern woodworking axiom. But in my view that needs to be challenged.
Oh and I'll say it before Charles does, that 1" chisel you are working on is sharp enough now. It doesn't have to be perfect to be functional and its not going to stay perfect for long anyway.
Adam
All you need is a flat back at the edge even a 1/16" flat area is fine.
If the entire back is flattened over the year repeated sharpenings and burr chasings will turn it convex and the chisel will be destroyed.Register the entire chisel on a stone but only apply pressure at the tip.If you think an entire plane or chisel blade must be flat or it will not register or work correctly please explain why for the past 500 years Japanese edge tools used for really amazing joinery have an intentional hollow and western edge tools, also used for joinery, including long paring chisels, are also intentionally slightly hollow in the back as a result of heat treat.The slight hollow makes it easier to sharpen repeatability over the years. that's why it's there. DON'T get rid of it - you will destroy the tool. Joel
http://www.toolsforworkingwood.comps - adam I know we are on the same page here but I just added my post to the end of the thread
Edited 11/10/2007 7:20 am ET by joelm
If the entire back is flattened over the year repeated sharpenings and burr chasings will turn it convex and the chisel will be destroyed.
Wow, my chisels have been "destroyed" for a decade or more and I didn't even know it!
Seriously, Joel, I don't know what chisels you think are good, but I have some LN's in my drawer (among many vintage ones), and they come with a flat back. Are they certain to be detroyed in no time? Do the Ashley Isles you sell come with flat backs? If I get an old swan with a minute convex back and flatten it out, am I damned to destroy it?
"Seriously, Joel, I don't know what chisels you think are good, but I have some LN's in my drawer (among many vintage ones), and they come with a flat back. Are they certain to be detroyed in no time? Do the Ashley Isles you sell come with flat backs? If I get an old swan with a minute convex back and flatten it out, am I damned to destroy it? "IIRC and I could be wrong - part of the instruction David Charlesworth gives in setting up chisels is a method for honing the backs of chisels - yes flat LN ones - so that you get a minute hollow. all you are doing with a flat backed chisel is making more work for yourself. Iles chisels - while not 100% consistent - are made traditionally which means that they are usually slightly hollow. Your swan chisel was made the same way. If someone hadn't make it convex, and you hadn't been forced to make it flat it would be even easier to sharpen and perform a little better and save you time. I get a fair number of customers who walk into my shop with chisels and plane irons - some bought from me, some from my competitors and they are desperate to get them working. But because of bad advice they have spent so much time "flattening the back" that the tip is now convex and the only solution I can think of is grind the edge back. note: I sharpen a lot of things for a living. every second I can save not fixing a bad edge is important to me. Joel
http://www.toolsforworkingwood.com
Edited 11/10/2007 11:19 am ET by joelm
Hey, I'm happy to learn if I can do something better. The Japanese chisel hollow make perfect sense to me - the areas near the cutting edge and the long sides are all that need to be flat, and getting them flat is a lot easier if the belly is hollow. That said, I cannot for the life of me imagine a technique with a sharpening stone (as opposed to say some kind of grinder) that would hollow out the middle/belly portion. What does Charlesworth do to achieve this? Does it involve two rulers?? ;-)
Joel, off topic, but real quick - I have your saw kit, but am confused about one thing as I read the excellent directions: I am unsure of what part of the "cricket bat" needs a belly - in other words, I'm having trouble picturing the cross section and what part I shoold be tapping on the teeth. Can you help? Thanks!
Edited 11/10/2007 12:38 pm ET by Samson
the cricket bat should be gently bellied side to side on the bat part that hits the saw. this way when you whack the blade in and hit the blade a little off center you are still getting a solid stroke with the bellied part of the bat.
Joel
http://www.toolsforworkingwood.com
"...I get a fair number of customers who walk into my shop with chisels and plane irons - some bought from me, some from my competitors and they are desperate to get them working. But because of bad advice they have spent so much time "flattening the back" that the tip is now convex and the only solution I can think of is grind the edge back...."
Sounds like classic dubbing to me. Tell them to toss their sandpaper and/or start maintaining their stones flat. Oil stones are a lot easier to keep flat than water stones but both require maintenance.
it's a whole bunch of things. you lay a chisel on a stone, push on the tip, get the area at the edge flat, instead of stopping you think you have to do the entire back. By the time you are done, all the pressure on the tip rounds the back, Or you think - I'll flatten my water stones when I'm done with this chisel.Or you use a really coarse water- stone - notoriously soft, If the sandpaper is PSA backed that will at least stay flat. and of course stones that aren't maintained make the problem even worse. So much trouble can be avoided by not trying for overkill in the first place.
Joel
http://www.toolsforworkingwood.com
Yeah, but as I said--it's dubbing. Dubbing has a lot of different causes but the results are the same. Most dubbing is due to poor sharpening equipment or poor technique. Rather than say, "Don't flatten too much," I think it's better to explain proper technique and sharpening stone maintenance.One of the problems we often have around here revolves around definitions. Sharp and flat are good examples. One person's "sharp" isn't necessarily the same as another's. My guess is that flat means different things to you and me. I have and still do use sandpaper for some sharpening. I now only use it for the initial flattening of freshly heat treated irons and am careful to stop before the dubbing becomes more to remove than the remaining distortion from heat treating. I no longer use water stones, they just wear too fast. My oil stones are dressed flat before each use and the coarse India is dressed multiple times during flattening a single iron. The translucent hard Arkansas I bought from you wears fast enough that it needs to be flattened for every iron or use. If all three of the oil stones I use; coarse India, medium India and hard Arkansas, don't cut in exactly the same place it makes my work too hard. It's easier to properly flatten a stone than remove enough metal on each stone to get the abrasive fully working the edge.After the initial flattening I do all my sharpening just a medium and fine oil stone. After I move from the medium to the fine, if after six or seven strokes, see any abrasive signature of the medium stone from the edge back 1/2" to 3/4" or so, I know one of the stones is out of flat. I fix that before I go any farther.My experience with sand paper is that dubbing is inevitable. To me dubbing, any dubbing, represents loss of control of the process. Although it can be slight, sandpaper rolls ahead of the tool being sharpened and raises just at the beginning of the tool. This creates a small dubbed area right where it has the most negative effect, at the edge. This causes dubbing and makes repeatability impossible when grits are changed.
I'm not going to argue that poor technique can result in dubbing. Duh! Part of poor technique is trying to flatten the whole back when initially sharpening a brand new chisel or blade. The back should be slightly hollow if western, definitely hollow if Japanese, and removing that hollow from the get go makes life much much harder.Joel
http://www.toolsforworkingwood.com
The back should be slightly hollow if western
This is the part that confuses me, Joel. I must be the unluckiest SOB around as I've bought LOTS of vintage and new Western chisels (Stanley, Swan, Witherby, Butcher, Buck, E.A. Berg, Keen Kutter, PS&W, Samson, Union, Lie Nielsen, etc.) and plenty of vntage and replacement (Hock and LN) plane blades, and have yet to run into any that seemed purposefullt "slightly hollow." Are all mine duds and rejects? and I didn't even know it until now?? What brands reliably come with the slight hollow?
Oh, and FWIW, any woodworker who grinds the hollow out of a Japanese chisel, well, he or she prolly shouldn't be working with sharp tools anyway, if you know what I mean.
interesting, just about every antique iron blade what have you which I own is slightly hollow where it hasn't been honed. Ray Iles explained it to me. The hardening of chisels and plane irons is done before the bevel and cannel is ground it. This is to mimimize warping. But the iron will warp a little (long paring chisels and other very long tools are corrected at the forge in the seconds after hardening - but that's an art in itself). If you are really good you will typically get a few thou of concavity on one side or another.
Then you check which is is concave and grind the bevels and cannel on the other side. The key point is that a concave back can be easily flattened at the edge and stay so as it is use and resharpened. A flat back might be able to stay flat if very carefully sharpened. A convex back on the other hand is nearly impossible to flatten and therefore undesirable at all costs. Joel
http://www.toolsforworkingwood.comPs - reflecting back I am willing to bet that part of the reason people treasure the old tools and say things like "they sharpen up real easy and hold an edge" is because on the latter point the steel was good and on the former point they didn't realize that the tool was a couple of thou hollow.pps - Until Ray told be as a by the way in another discussion I never knew this and thought I was just being lucky when so many of my old tools (basically all my tools are old) sharpened up easy at the edge. Then after he told me I went back and checked and gosh darn it he was right. Edited 11/12/2007 10:24 pm ET by joelm
Edited 11/12/2007 10:26 pm ET by joelm
I'm a sucker for vintage chisels. I have a full set of 750s and Swan bench chisels, and my paring chisels are mostly Swan and Witherby. I have many others too by various makers as I mentioned, and I love using them all.
While wide for an individual, I know my experience is limited in the larger scheme of things. I'll look harder for those hollows from now on. My experience to date has been that every chisel seems to have its quirks as far as low and high spots on the back. Some are much better than others, but I haven't noticed a consistent pattern of hollows. For the record - I would never bother to flatten a chisel back to get rid of hollow in the middle of the blade. I'm only working the back until there is a flat at the business end - but will usually register much of the back on my stones while doing so - so sometimes, a high spot here and there further back needs to come down some, and if the front edge area needs lots of work, I need to work the rest of the blade as well in order to keep things in the same plane.
Thanks for your thoughts as I'll now be more sensitive to trying to make sure that if a hollow exists, I'm not blowing right by it somehow with a coarse grit.
I think there may be a flaw in your logic, Joel. I guess it could be that you have only bought primo new old stock tools.My experience has been the opposite. Most used old tools show almost radical dubbing from a hollow stone. Most old tool chests seem to have only one honing stone and my guess is that's because the old guys didn't have a good way to flatten their oil stones. Most of the old stones I see in those chests are hollowed pretty badly. If you can't flatten them, there's no repeatability and sharpening on more than one stone becomes an exercise in futility. The reason I limit the number of stones I use is an attempt to make taking care of the stones manageable. When I read of someone using half a dozen or more grits, I shake my head and know the odds are that I wouldn't be happy using his tools.
"I think there may be a flaw in your logic, Joel. I guess it could be that you have only bought primo new old stock tools."yip - I'm not talking about saving some old tool that's been beat up, then flat is better than convex or you toss the tool. I'm talking out of the box, the way a tool was intended to be sharpened. "My experience has been the opposite. Most used old tools show almost radical dubbing from a hollow stone. Most old tool chests seem to have only one honing stone and my guess is that's because the old guys didn't have a good way to flatten their oil stones. Most of the old stones I see in those chests are hollowed pretty badly. If you can't flatten them, there's no repeatability and sharpening on more than one stone becomes an exercise in futility."Absolutely. "The reason I limit the number of stones I use is an attempt to make taking care of the stones manageable. When I read of someone using half a dozen or more grits, I shake my head and know the odds are that I wouldn't be happy using his tools."Not a bad logic. I don't know if I 100% agree with you but you are not far wrong. If nothing else trying to maintain 4 stones is twice as much work as maintaining 2 stones
Joel
http://www.toolsforworkingwood.com
Edited 11/12/2007 11:03 pm ET by joelm
Joel, thanks to you and everyone else who replied. This has been a very enlightening discussion. I'm glad I brought it up.
Larry, I can't be 100% sure you are right about sandpaper, but I have always felt that I didn't get as good an edge off sandpaper as I did with a stone. Maybe your theory is why. (Now that I have said that, I fully expect at elast one person to jump in and tell me I am a fool because they can do it just fine and can shave with their sandpaper-sharpened irons and chisels.)
And I know I lumped myself in with that group of guys you mentioned who use half-a-dozen grits, but that is not my standard practice. I wanted to see if all the in-betweens made any difference. They really didn't, and I'll probably be selling off the 2k and 6k stones.
The thought that a small hollow is desirable never occurred to me; but then I'm not that up on Japanese chisels. The idea makes sense.
Most nights are crystal clear, but tonight it's like he's stuck between stations.
I was taught to look for chisel backs with slight hollow in the length and to reject chisels with a belly in the length, in the early 70's and that advice came directly from a craftsman who probably trained in the 20's or thirty's.
Flat chisel backs can be minutely hollowed by keeping the edge of the tool off the side of a stone for 50% of the strokes used. I have developed and described two movement sequences, (with such exciting names...) movement 1 & movement two, which I use on waterstones to counteract their softness, and tendency to hollow in a flash.
see. dvd 4 or book 3 pages 84 to 93 "A guide to Hand Tools and Methods".
I expect these movements will work on other stones too.
We use a set of 3 waterstones, 800, 1200, and polising on 6, 8, or 10,000 grit.
Most old tools show signs of being sharpened for years on hollow oilstones, i.e. a falling away of the back near the edge and some dubbing of the long edges as well. It can be very time consuming to get these flat or slightly hollow in length, even for the minimum inch or two that is necessary.
This was not a great problem for the individual as long as the same stone was used for ever, as the blade backs simply matched the poor shape of the stone. However if a new flat stone is used nothing works, as the edge no longer touches the stone and the wire edge cannot be honed away.
Larry's technique of flattening his oilstones every session and more often on the coarse sounds very good to me, and it is the first time I have heard of such rigour.
I would also confirm that every tool I have ever seen sharpened with scary sharp exhibits dubbing to some small degree.
best wishes,
David Charlesworth
Edited 12/8/2007 10:44 am ET by david charlesworth
I can't tell you how many dovetail pins I've split doing exactly what Samson showed.
Forgive me for saying so, Adam, but I think you may want to reexamine your technique. I've never split a pin or had any other problem. I do agree that it is best to work from various angles as pin is brought down to flush (same with dowel pins, etc,). I took for granted that folks would know that the cutting in this situation is best done with a shearing/slicing action wher the registered chisel is pivoted so the cutting edge is moving in an arc and the wood fibers are sliced. If you just push straight ahead, I can imagine all sorts of problems.
And, Joel, did you actually read the prior messages, or look at the diagrams? If so I think you'd see we are in agreement. You said: "Register the entire chisel on a stone but only apply pressure at the tip." The need to register the entire back (especially at coarse grits) was my point - because otherwise you can easily produce a convex back by removing material from the tip area and leaving material further back (i.e., you may create a fulcrum). I also never said to grind out hollows on Japanese chisels or anything like that. As long as the bit near the cutting edge is flat, and nothing behind it is significantly higher, hollows are of no consequence.
Samson,
There are a lot of posts in this thread, some conflicting, some confusing, and I suppose you would include my post in this category, some redundant.
I have however seen so many convexicated chisels and plane blades (perfectly fine blades that were made convex by over flattening) that even if I am being redundant it procedure bears repeating. Joel
http://www.toolsforworkingwood.com
"Forgive me for saying so, Adam, but I think you may want to reexamine your technique."Well, let's talk about that. Regardless of the motion you use, you will inevitably end up with some little piece of material that must be attacked from the far side. Sometimes working from the far side, I can sneak the corner of my blade between the pins so I have a little land there. But in that instance, bevel up or down is regardless insofar as registration goes. The amount of contact being the same either way. So I find laying the chisel flat on the case side unhelpful and needlessly risky.The other issue for me is that I almost always push the chisel with my shoulder which gives both more control and more power. The technique along with its unorthodox grip was desribed by Moxon. Like Moxon said, I've found that even when I am not pushing with my shoulder, I use this (bevel down) grip.So I guess my point is, the technique you desribed is the one I have found folks use to justify the functional requirement for a flat backed chisel. I think the technique is fine- whatever makes you happy and works well. But there is an alternate method, possibly more effective, that challenges the flat back requirement. It also may help explain how folks in the past got on without glass or granite lapping plates. Adam
Regardless of the motion you use, you will inevitably end up with some little piece of material that must be attacked from the far side.
Not so. The little pieces can be attacked from various angles including at 90 degrees to the top and bottom edged of the drawer (i.e., parallel to the front). You have a great deal of control when moving a chisel edge through a slicing arc. Depending upon the direction - clockwise or counter clockwise) you can easily eliminate break out risks and get very clean cuts.
And it's not only for dovetails. It can be used in all sorts of circumstances where two boards that are supposed to be flush are slightly proud here or there (rails and stiles, for example).
Try registered slicing, Adam. I think you'll find it is better in many circumstances than brute shoulder force pressing forward.
Just checking to see how you were making out and to add my own
two cents to this discussion. My take on this is that "flattening"
is really only well understood by gauge makers and lens makers.
Because these processes have come so far in recent years there
are only a few practitioners of the manual art left. Most of these are
amateur astronomers with a passion for building their own gear.
The general idea is by rubbing two similar objects together
with an abrasive grit between the two objects, one of the objects
will go concave and the other convex.
In discussing "why" this happens you can go off on very long tangents.
This inevitably leads to long rants about what is sharpening, lapping,
grinding, honing, fetling and so on. For the pupose of this rant
we are simply discussing how something could be "flattened".
But...
A fairly significant reason is "length". Take an abrasive block,
say a cheap Chinese sharpening stone, 1/3 the length of your
chisel back. Fix the chisel in place with the back roughly horizontal
and facing you. Rub the block back and forth on the surface of
the chisel. You will "to a certainty" develop a hollow.
If you now take your hollowed chisel, fix in place an abrasive block
that is 1.5 times or so the length of your chisel back. Now rub the
chisel lengthwise on the abrasive block you will, inevitably "belly" your chisel.
Balancing these two tendencies is "flattening".
For chisel flattening simply use the coarsest medium that
will allow a comfortable rate of stock removal. You can use
steel blocks with diamond pastes or just a chunk of cheap
Chinese aluminum oxide, sandpaper glued to a steel, aluminum,
or anything reasonably flat will have a similar effect.
Use a straight edge of some sort to gauge your progress.
(I use some cheap Chinese machinists parallels).
Place the straight edge on the chisel back. hold the assembly
up to a light. Try to hold the assembly in such a way as to
not bend the chisel. (Really easy to do) You will see
a sliver of light that will tell you where you are making
contact with the straight edge and where you are not.
Once you have contact with the tip of the chisel and somewhere
near the back you have a "hollowed" chisel. To "flatten" this
"hollowed" chisel rub it back and forth on an abrasive that
is longer than the chisel. Gauge with a light sliver and you will
go a reasonable way to "good enough"
There is a bit more to it than this ...
- How to stay straight ( no not the AA kind)
- How to fix a potato chip
- how does this apply to planes
- how does abrasive choice infuence the results
- Is this grinding, lapping or neither
but this is the gist of it
Rule of thirds and which object is moving...
Best wishes
Al
Urbman
I read your stuff on rubbing two things together with grit between them. I flattened my chisels on diamond stones. I checked. The diamond stones are still flat. Did I do something wrong?
Why not use diamond stones to flatten other types of stones?
I kinda like diamond stones.
MelMeasure your output in smiles per board foot.
Sorry for the overly simplistic description. In the case
of diamond stones you have a couple of great things going for
you. One is that the diamond particulate is nicely and evenly
bound to the substrate. Second, at least in the case of
the one diamond stone that I have it was and is still is quite
flat. So I have not tried to recondition it.In the case of using diamond stones to flatten silicon
carbide, novuculite or aluminum oxide stones my guess is that
it would work just fine. Similar to using silicon carbide paper
on a piece of steel. I am of modest means and have easy access
to bits of steel so I tend to go that route. The only caution
I would make would be that diamond stones were pretty expensive
and so I would not use them to flatten a cheap stone.
Diamond fractures just like any other media albeit more slowly.
It would be a poor trade to soften the cut of a good diamond stone
in order to restore an inexpensive silicon carbide one.However a vintage grade one translucent arkansas might be
worth the risk :-)My collection of cutting tools are basically old ones that
seem to have been used as pry bars, gardening tools and
paint scrapers :-). As you might imagine I tend to have to
remove a bit more stock than one might if I had a "new"
chisel.How are your chisels turning out ? Are you working with
derelicts or relatively new or reasonably well made chisels.Best wishesAl
Al,
"How are your chisels turning out ? Are you working with
derelicts or relatively new or reasonably well made chisels."Thanks for the great response. I also am a man of modest means, and I will retire in two weeks. So means will become even more modest. I was able to get some diamond stones very inexpensively. I haven't spared them. I use them to flatten the backs of chisels and plane blades and have used them to flatten an Arkansas stone. I use them on my gouges. I do a lot of carving. We will see when and if they give out. Until them, I plan to use them.I have some old chisels and planes and some new. They work fine. The diamond stones have done the job. After diamond, I end with the super fine Spyderco ceramic stone. It shines the edge up beautifully. I got some spyderco slips and I use the slips and the stone to hone all my carving gouges. When carving, I just hone on the Spyderco stone and slips and things go well.It was good to meet you. Thanks for sharing your wisdom. That is what Knots is all about.
MelMeasure your output in smiles per board foot.
Mel,
Can you direct me to Spyderco's ceramic stones? I have their WEBsite and I see they are primarily into knives but sell sharpening stones as well. I'm curious as to which ceramic stones of theirs that you use for your carving tools.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Bob,
Spyderco has a website but I got mine at Woodcraft. The big stone I use for final honing is:
(C) Spyderco Bench Stone Ultra Fine/2000 Grit 2" x 8"
#835912 Price:$64.99
You can see it at
http://www.woodcraft.com/family.aspx?familyid=20254
It is the one in the black case. It is the "finest" of the three. I have small versions of the grey stone (600 grit) and the finest one (2000 grit) which I got with my Wayne Barton chip carving knives. That is where I learned to appreciate what they can do. After using the finest, I tried using a leather strop with green rouge and it was a step backwards, so I stop with the ceramic stone. Spyderco makes three stones, but the middle stone is so close to the ultrafine stone in grit that it doesn't make sense to get it.The spyderco slipstones I use are
(F) Spyderco Ceramic File Set Fine/1800 Grit (4)
#835913 Price:$39.99
You can see them on the same webpage as above.
One doesn't really need all four of the slips. There is one that is wonderful for V tools, and two that are great for gouges, but only one of them is necessary. Unfortunately they only sell them as a set. You don't want to drop these on a stone floor :-)I am not sure that I am in the mainstream, using the Spyderco stones. I know a professional woodworker who teaches carving, and he now only used the spydercos on his gouges. I use my finest diamondstone and then move to the Spyderco ceramic ultrafine. Once I have used the diamondstone on a gouge once, I rarely go back to it. I just go back to the Spyderco.But, I can get results which are just as good with sandpaper, and almost as good with oilstones. I still haven't tried waterstones.
Hope that helps,
Mel
Measure your output in smiles per board foot.
Retire in two weeks? Is this your Christmas present to yourself?
T.Z.
T.Z.,
Retiring in two weeks is my way of recognizing that I am almost 65, and have been working steadily since Jan. 1970, after having put in 10 years in three different universities. It is not a "Christmas gift" so much as a recognition that, while thoroughly enjoying NASA since 1979, there are other things that need doing, and many of them are made out of wood. There are precious few wooden spacecraft these days. I wish I was young like you. I like hanging around with you kids. It makes me feel young.
MelMeasure your output in smiles per board foot.
Thanks for calling a 55 year old a kid! I needed that for a Monday morning!
T.Z.
Tony,
Hey you young whippersnapper!
I like hanging out with Mel, makes me feel younger!
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 12/10/2007 11:27 am ET by KiddervilleAcres
Well, I like hanging out with older gents as it makes me wiser!
T.Z.
This is getting way too sentimental and soppy here. We need some conflict!
-Steve
Arguments are 50¢, down the hall, second door on the left!
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Congratulations !
I will use this as an excuse to tip a dram of "aqua vitae" in your honor. If I could impose on you for a bit of "off topic" advice
I would surely appreciate your time.Among my collection of derelicts, I have some gouges. While
I have had some success with the "out-cannel" type
I am having none with the "in-cannel" variety.As you probably guess these are not in good shape but rather
require serious attention. Would you know how these were
ground in the first place ? Perhaps a tip or two on how to rough in the "in-cannel" and
perhaps a tip or two on refinement ?( I have read Leonard Lee's missive on sharpening but he
seems to assume a reasonably well formed tool to begin with.
Later he dismisses the patternmakers gouge outright. Fair enough
but that is what I wish to restore :-) )Cheers !AlPS what does 9619 mean ?
Al,
What does 9619 mean?It is the street number of my house.
I had no idea what I was getting into when I started Knots, and they wanted a screen name, and I just wrote down my street number. Not very creative, huh?In-cannel gauges in rough shape.
My suggestion is to try those sandpaper covered cylinders that you can put in your drill press. Use one which is close to but smaller than your gouge. Turn the drill press on with not too much speed, and just touch the bevel to it lightly and move it around to cover the entire bevel, and then pull it away gently and look at it to see what you have done. Adjust your angle as necessary, and increase the speed if you feel the need. Work SLOWLY. Don't let it heat up! You can get these cylinders at Woodcraft so that you can replace the sandpaper with regular flat sandpaper. You just loosen a screw, cut the paper to size, put it in and tighten the screw. That way, you can start with rough sandpaper and move up slowly to very fine sandpaper.There is another way. Start with a wood dowel that is smaller than the gouge. Glue some sandpaper on it, and go to work. There is less chance of doing damage than using a drill press but I like the drill press better. If I didn't make any sense, write back, and I'll try again.
Have fun.
MelMeasure your output in smiles per board foot.
Mel,
Funny, how everything you recommend lately (spyderco stones, sanding spindles) can conveniently be found at Woodcraft...
;-))
Ray
Ray,
"Funny, how everything you recommend lately (spyderco stones, sanding spindles) can conveniently be found at Woodcraft..."Yup, and it can be found at Rockler, and at Tools for Working Wood and at 150,000 sites on the web. What did you think of my recommendation on how to sharpen in-cannel gouges? MelMeasure your output in smiles per board foot.
Al,
In your example of rubbing stones together and going 30% over length with the stroke, What happens to the width of the two stones please? And how are we to control flatness of width.
Or are there any sources of principles used by lens makers.
best wishes,
David
Procedures in Experimental Physics by John Strong
available as a reprint from Lindsay BooksHow to Make a Telescope Jean Texereau
available in English Amazon or BiblioAmateur Telescope Making" Book 1 Twyman likely in the library
or in virtually any astronomers personal collection.
(similar to a woodworker likely having a book by Frid or
Krenov)Things vary a bit with each specific case.
In this case let's stipulate that the two objects are the same i.e. two stones of similar composition, stones that are of
similar hardness and the same in length and width.Further lets stipulate that the abrasive is silicon carbide.So we begin with the distribution of the abrasive
I use kerosene (paraffin) applied with a brush, I sprinkle
the abrasive on so that I get about a 10 to 20 percent
coverage that is I spread it around evenly but the
surface is darkened to the extent that about 20 per
cent is visible.When we begin to rub the abrasive will collect in
the low points and roll over the high points. Fractures
will occur in both the abrasive and both targets.During these initial strokes much is dependent on the
initial shapes of the targets. In the direction of
of the stroke, you will begin to realize the concave
and convex shapes of the moving and stationary targets.Clearly by ommision, this isn't improving anything in
any other axis.Lens makers and gauge makers address this issue by
rotating one or both targets. They equalize the effect
of the abrasive particles by linking the ratio of the
stroke count to the rate of rotation. They use the
term "grinding" to describe this activity.So how does this apply to flattening...If you examine the results of our little effort
you might note one of several conditions two of
which I see often. In one case you get something like a butterfly.
This, in my case at least, is caused by the moving
object, flopping back and forth on the forward and
return strokes. This happens to me fairly often
because I tend to violate the rule that the two objects
should be the same in length and width.
The moving object in my case is often wider
than the stationary object. (Think of a 1/4 inch
chisel and a 1/2 inch wide block of steel.Turns out that as long as the two objects are exchanged
(moving object stationary, stationary object moving)
often enough this effect is "corrected" sufficiently
for at least my purposes. The correction is most often
due to a re registration of the two objects. This re registration
has to be followed fairly closely when you are making something
like parallels but in the generation of independent flat surfaces
it can safely be ignored. Lens makers would be appalled at such
a flip remark :-)In the case of stones sufficiently wide say 2inches or wider,
this is easily addressed by rotating the stones 90 degrees and repeat.At this point you can let your inner anal retentive daemon
run wild :-) Construction of a Hindle type grinder and
you are well on your way to .000005 in 10 inches.
Thank you.
I will try to find one of those books.
David
Mel,
Yeah, but Woodshafts' tools are betterer than those other guys', though.
Your description of a means for grinding an incannel gouge sounds good to me. The few incannels I have were all in good shape when I got them, and I only use them for coping moldings, so they don't get used hard in my shop.
As an aside, I have found that small dia grindstones (on a shaft like a router bit) don't "eat" very fast, as their peripheral speed is so slow, compared to the edge of a 6" wheel spinning at a similar rpm. So if I were grinding incannels for a living, I'd be inclined to shape the edge of a narrow wheel to the correct profile and go that route.
take care,
Ray
Ray
The only in-cannels that I have done are adzes, and they are a bit wider than most gouges. As always, I took my time sharpening them. No hurry in my sandbox. If I were doing this for a living, I would have starved a long time ago. And, you know, I would have been the first Italian ever to starve to death.You said something about sharpening in-cannels for a living. If I had to face the thought of sharpening anything for very long, I would run far and fast. The only reason I sharpen is to make the tools work better. I have given up on achieving a "sharpener's high". I am also giving up on achieving an "adze high". Mostly what I achieve is the need for an ibuprofen. Maybe those guys who use a lathe are onto something. Let the wood come to the cutter. Now if I could just do that while achieving a non-round shape, I would move more smartly in that direction. MelMeasure your output in smiles per board foot.
Son, it sounds like you need to learn to pace yourself. Ever hear the one about the young bull and the old bull?
I do wonder what the 18th century terms for carpal tunnel, repetitive stress and rotator cuff were. Mebbe that is even in the Roman Woodworking book...
I read something once about the axe sharpeners in a Sheffield factory. They worked lying on their stomachs on a board which pressed the ax against the huge grindstone, which was sprayed with water. Now that sounds like a fun job. Like being in a waterpark ride, summer and winter.
Not only my knees, but my wrist and shoulders go clickety-clack when they move back and forth.
Ray
Mel,
Now tell the truth; you just like dubbing around. :-)
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
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