Can I use a 220 grit Norton waterstone to start flattening the backs of my bench chisels? I’ve heard that the 220 grit is too rough and will leave marks that will be difficult to remove with the next, 1000 grit, stone. So far, I’ve started with 1000 grit and worked my way to 8000 grit, but this process took me about 2 hours of constant work for a 3/4″ Marples chisel (just working the last 1″ of the chisel back). I would like to purchase a set of Two Cherries chisels but I don’t want to spend 10 hours flattening the backs. Should I invest in a 220 grit stone (I have all of the other grits) to quicken the process or is there a better way?
– Lyptus
Replies
I'm certainly no expert in this area. My sharpening experience is very limited. I just went through the same task of flattening the backs with my set of Marples chisels. It took me about two to three hours for the whole six chisel set, but I did use the 220 grit stone for some work on each chisel. I could actually spend some more time on a couple of the chisels and will need to do that at some point because I'm not fully happy with the results on them. The backs on those chisels was way off. One would hope that Two Cherries chisels and other higher priced chisels would have flatter backs "out of the box" than the Marples, but I haven't looked at them.
There is really no such thing as too rough a grit to start depending upon the work at hand. Scratches are much quicker to remove - i.e, shallower - than the peaks and valley's of a non-flat back.
Your issue may be jumping from 220 to 1000. It make take a 1000 grit substrate a while to wear as deep as a 220 grit scratch. That's a pretty big leap. 320-400-600-800 sandpapers and stones are available.
"Your issue may be jumping from 220 to 1000. It make take a 1000 grit substrate a while to wear as deep as a 220 grit scratch. That's a pretty big leap. 320-400-600-800 sandpapers and stones are available. "This is undoubtedly true. Just be aware that sandpaper grits are not exactly equal to waterstone grits. 220 grit sandpaper is a little bit finer than 220 grit waterstones, and a 1000 grit waterstone is about equal to 600-700 grit sandpaper, depending on whose waterstone it is.
Also, go watch this video where Garett Hack addresses teh flattenting issue as he revives a flea market find:
http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=28817
Hi Lyptus
I wrote an article on this not too long ago. It is here.
Regards from Perth
Derek
That, sir, is a very nice article.
I've started with the 220 grit Norton stones many times. Only thing I would advise is make sure you flatten the stone often (this may need to be done several times during the initial flattening of a single chisel, depending upon the starting condition), as the 220 wears very, very rapidly.
I have found that a coarse diamond plate (the DMT ?) is pretty good for quickly flattening the back of a chisel or plane blade. (For some reason, these diamond stones are really aggressive during the breaking in period. Hence a new fine plate I have cuts better than an older medium one (right now)). Anyway, depending on the quality of the flattened surface, I may go on to a finer diamond plate or go up to an 800 grit waterstone and then on to 1200 and 4000. This goes pretty quick--10-15 minutes or so max.
When flattening the backs of blades, note that only the last inch really needs to be as smooth as the bevel.
You can muck about with diamond stones, even the extra coarse variety (40 microns), but these are still not in the same category as 80 grit sandpaper (about 180 microns) or 120 grit sandpaper (120 microns). A few l-o-n-g strokes on 120, followed by 180, 240 and 360 ... and you are done. Just add 600 and 1200 to the area behind the bevel.
View Image
Regards from Perth
Derek
Thank you all for your comments. I think I'll go with the sandpaper approach. Would a granite tile plate from a home improvement store provide a flat enough surface compared with float glass? I've had trouble locating float glass from glass shops in my region.
The glass doesn't matter that much - particularly if you are doing your final surfacing on water stones. You just want to remove the machining marks quickly. The critical part comes when you get to the 4000/8000 range.
What about removing the lacquer? I've tried that on Marples chisels with a one-day soak in Lacquer Thinner but it wasn't very effective.
I wouldn't worry about it. Just wipe them down with what ever you have (removing any chunks) - mineral spirits works well.
Since you are new to sharpening I'd suggest getting the "complete guide to sharpening" by Lie-Nelson - published by the beloved Taunton Press. It covers a ton of topics and will get you going. Sharpening, like woodworking, is a skill that comes with time... and, like woodworking, there are many different methods to accomplish one task (I have a Tormek... but find myself using Norton waterstones)
In the end, you should try to keep all of your cutting edges sharp enough to shave with. The tool will be much safer and you will enjoy using the tool a lot more.
When in use, you will know the tool is sharp when you see blood... and you don't know where it is coming from :0)
Hi Lyptus
Float glass is used everywhere. Just get an offcut from your local glazier.
In response to "The glass doesn't matter that much - particularly if you are doing your final surfacing on water stones. You just want to remove the machining marks quickly. The critical part comes when you get to the 4000/8000 range", I must respectfully disagree (unless I have misunderstood).
It is important that the initial stages of flattening are completed accurately. You are grinding away metal and preparing the surface. Later grits only serve to refine this surface. If you cock up the 120 grit, then all you will do is polish this up, not remove it. 4000 and 8000 waterstones are polishing stones. They will not remove metal (other than scratches), and therefore they will not flatten it.
Additionally, there is less work involved when your strokes are long, therefore get a long sheet of glass. My lapping table (see the article link I posted earlier) is 1m in length. This is 10mm thick float glass (contact) glued to three layers of 3/4" thick MDF, and the whole lot is clamped to my bench top when needed. I use poster contact glue (which has a weak adhesion and is easily removed) to fix the sandpaper to the glass).
Do it correctly once, and then forget it.
Regards from Perth
Derek
my comment was in regards to float glass. Any "flat" hard surface will do. While it is nice to flatten the back within .001 inch... and the flatter the better, a piece of regular glass will work just as well as a table saw table or a piece of tile from the local home improvement store. Sharpening can be done simply, with inexpensive supplies -or- it is something that you can invest hundreds... or even thousands of dollars in to.
I'd suggest that if anyone is learning the skill- start with the scary sharp method. It only requires a small investment in sandpaper and some "cheap and flat" surface. Try sticking some sandpaper to the bed of your jointer or tablesaw. I'd guess that everyone has one of those handy :0) If you have trouble finding sandpaper above 600 grit, try going to an auto-part store. They will likely have the grits that you're looking for. 220, 320, 600, 1000, 1200 or 1500 and finish up with the 2000.
Regarding "float" glass, just so that no one thinks that this is a special type of glass or going to be hard to find, it is basic "regular" glass. This is just the name given to it, as I understand, and comes from the process of manufacture. Just get regular glass from your glazier for this purpose.
It is the substrate to the glass that is important. Glass will bend, even thick sheets, so beef it up with something like MDF.
Regards from Perth
Derek
"I've had trouble locating float glass from glass shops in my region."
It has already been noted that "float" glass is regular glass, though I'm not sure what "regular" glass is.
I found a product at my local home center that I think works great. They sell glass shelves (found in one of the several shelving sections they have). These particular ones (image attached) come in a wide variety of sizes and have 1" or 1.5" holes predrilled in the corners (dependng on the shelf size). They are made of tempered glass which I feel better about using. It can be expensive to have made to size and since they don't cut it, you can't find cheap "cut-offs". They also sell corresponding hardware that fits the holes which you can use to mount the glass to another surface. This is "tidy" and also handy as you can outfit a couple different shelves with different grits of sandpaper and swap them out if desired. I chose 12x24 but they come in 16x16, 12x36, and other sizes (and shapes). The best part is the 12x24 was less than $10.00, the 12x36 was only about $16.00. Other sizes were similarly inexpensive.
Nice suggestion! Thanks!- Lyptus
I found a chunk of faux marble counter backsplash at my local home store. The corner had been damaged, so they sold it to me for $4.
It is hard, smooth and flat. And cheap.
THe glass places I called wanted $40 or more for a piece of half inch glass with the edges polished enough to not be a safety hazard. Seemed steep to me so when I found the backsplash it was an easy choice.
-Tom H . Ventura, CA
Tom
Just to repeat, you do not need thick glass - you want something that will lie flat and smooth on the top of a suitable rigid and flat surface. Hence my glass on MDF. The glass - or countertop - just makes it easier to clean up contact glue and be re-used.
You can easily remove the sharp edges of freshly-cut glass on a diamond stone or with W&D sandpaper. I bevelled the edge on mine with 325 grit.
Regards from Perth
Derek
Hi Derek.
Thanks for the comments. I was worried about breakage for the thinner stuff... maybe not a realistic concern... but real enough to me. I don't have alot of room so everything gets moved around a lot and it just seemed like thicker was better.
And I'm not sure how much cheaper the thinner material would be; the shops here seeem to have minimum orders.
Never thought about polishing/deburring the edges myself... hmmmmm.
Hopefully the backsplash will do the trick.
-Tom H.
Whatever happened to Alan Bond? Did he ever recover from his bankruptcy? The America's Cup you folks put on down there was the highwater mark of AC competition. It has really gone downhill ever since.
Tom
Try not to mention AB - he is a dirty word in most Oz circles. Spectacular bankrupcy and millions..billions? of debts yet continues to live the high life after a nominal jail sentence. For all that, he did a power of good with the Americas Cup. It certainly vitalized Perth and it has grown from strength to strength in the 30 years since our victory.
Regards from Perth
Derek
Edited 5/25/2007 5:49 am ET by derekcohen
Find a stone counter top business. They'll have scrap pieces they'll be happy to see you haul away for free.The only problem is that I don't know of a way to use sandpaper sharpening without dubbing your edges. I suggest you avoid dubbing edges. You loose control of the sharpening process the minute you dub the edge. Remember the wear that results in dull edges is actually dubbing too. If you keep backs/faces flat, each sharpening actually does all the prep work for the next sharpening. IMO, intentional dubbing is as bad as accidental dubbing so avoid the "ruler trick."
Maybe this has been discussed before but I'm new to this so I'll ask. What did you mean when you said that you know of no way to flatten on sandpaper without dubbing the edges?
HT guy asked, "...What did you mean when you said that you know of no way to flatten on sandpaper without dubbing the edges?"
The paper backing deforms ahead of your edge as you sharpen. As it does, it rises up and rounds or dubs the edge. Ignoring the cutting geometry problems, lets look at the problems this causes in sharpening.
Ideally, the first stone or paper you use should be the coarsest and the one that does all the work. Subsequent stones or paper should only need to remove the abrasive signatures of the previous stone. If the edge is dubbed, you have either have to get at least the same amount of dubbing or you have to remove a lot of metal.
Just as each stone or abrasive should prepare the tool for the next, each sharpening should act as the prep work for subsequent sharpening. You can't do that if you lose control of the process at any point. You do lose control of the process with dubbing because the papers or out-of-flat stones won't cut in a uniform way. Keep your stones and tool backs/faces flat and sharpening will become a quick and easy task that will avoid the common issue of putting off sharpening. There's no way to keep out-of-flat stones uniform in the curvature but keeping them flat is relatively easy.
Let me point out that Charlesworth says to never use his "ruler trick" on a chisel. There are a lot of reasons for this and I think they apply to plane irons as well.
A properly sharpened paring chisel won't dig in because there is no clearance angle. The cut wood fibers, like sandpaper in sandpaper sharpening, deform ahead of the cut and spring back after being cut. This tends to lift the tool and pressure is required to keep the edge in the cut. Those having that problem need to examine their sharpening or technique.
I guess I have been missing something. I use wet/dry sand paper (220,320, 600 and 1500 P) on a marble slab and held in place by the surface tension of water. I finish with the micro-fine paper from Tools for Working Wood either on the marble or adhered to glass. I don't know whether the edges are dubbed, but I can get shavings from end grain of cherry or jatoba. I can also work the flat services beautifully with my planes also. This is my criterion of sharpness, i.e.-the tools do what I need. I have tried almost all of the other techniques and have not found them as easy or satisfactory as the above.
If you're happy with what you're doing and the results, stick with it.I use two stones to hone. A medium India and a translucent hard Arkansas. I also use a diamond stone to maintain the two honing stones and a strop. The whole setup takes up an area 18" X 13". From the time I decide to resharpen a plane or chisel to the time I'm back at work is literally less than two minutes unless I regrind for some reason. It's an easy painless process that actually encourages frequent sharpening and I doubt you'd have any problem with the performance of the edges.
You said you use a diamond stone to maintain the two honing stones.
What grit is the diamond stone that you use for this purpose?
Do you find that you have to flatten the translucent Arkansas stone often?
When you strop, do you use a compound on the leather or not? If so, which one?Thanks,
MelMeasure your output in smiles per board foot.
Mel,I dress both the India and Arkansas stone every time I use them and sometimes during use. This not only keeps them flat but it keeps the abrasive fresh and fast cutting. First I dress the Arkansas then the India and I leave the abrasive slurry on the stones. The oil stones cut nearly as fast as water stones when used this way. I use a coarse DMT diamond for dressing.Contrary to what a lot of people say, oil stones go out of flat pretty quickly. Not nearly as fast as water stones but pretty quickly. I don't think going out of flat is as big a problem with them as dulling and clogging of the abrasive. Dressing deals with both problems and it only takes a couple strokes with the diamond stone if you dress the oil stones frequently.The stop I use most often is impregnated with a product called Yellow Stone that I got at a WoodCraft store. It's maybe a little to aggressive and can result in dubbed edges if you're not careful. I also use chromium oxide on a couple other strops and it works fine.I also avoid honing guides. Honing guides can only work with the simplest straight sharpening and you have to be able to sharpen free hand to sharpen molding planes, gouges and a lot of other tools. I avoid all the unnecessary paraphernalia I can to save space and time. It would probably take me longer to install a chisel or plane iron in a honing guide than it takes to completely sharpen one free hand.
L,
I really appreciate your rapid response. I have never heard of the practice of using a diamond stone to dress a hard Arkansas stone and leaving the slurry on for faster cutting, and to eliminate clogging as well as to keep it flat. It sounds like a very good idea. Thanks for letting me know. Thank you also for your thoughts on stropping.What about sharpening and honing only using diamond stones and a strop. Are the finest diamond stones good enough to end with before going to a strop. I hear that there is a 1200 grit diamond super fine stone. (I use the term "stone" loosely.) That is probably not much different than your hard Arkansas stone as far as grit goes.While you are giving advice, do you have any experience with ceramic stones? I have two small ones that I use with my chip carving knife. They are Wayne Barton's brand. They work fine for that little knife. The medium stone is only for the initial shaping of the edge. The fine ceramic stone that I got is very slow cutting. It seems to be a finer grit than a hard Arkansas stone, and it puts a keen edge on the knife blade. Indeed, when I went over the knife with a strop, it was not as shiny as it was after I just used the fine ceramic stone. They recommend that the ceramic stones be used dry, and that you clean them with an abrasive powder, such as Bon Ami and a plastic scouring pad. I have never used these two small stones on other blades, and am wondering about what might happen. I would guess that they would wear well. They seem very hard. I would guess that they would tend to clog, since they are not being used with a liquid. I agree with you on the use of honing jigs. I have a Veritas but have stopped using it. I use sandpaper on glass. It works for me. I think about going to two stones, like you, or about going to just diamond stones, but am slow to move. Of course, that keeps me from collecting sharpening systems, as so many woodworkers have.Last thought - you flatten your Hard Arkansas stone with a coarse diamond stone and leave the slurry. Does that cause your Hard Arkansas stone to actually cut with a coarser grit/action than it would if you wiped it off good?The reason that I ask is that I saw a guy selling Tormeks, and he caused the Tormek stone to take a coarser grit and a finer grit by dressing it with a different tool. At least that is what he said he was going. If you scrape a Hard Arkansas stone with a coarse grit diamond stone, doesn't that make for a coarser surface on the Arkansas stone? and doesn't it leave a slurry of grit that was knocked off by the coarse diamond stone which is coarser than that of the Arkansas stone before it is rubbed with the coarse diamond stone.Sorry for the rambling? I am anxious to learn, and you posed some very interesting ideas. Sounds to me like your practices are based on a lot of experience, and that is hard to beat.
Thank you very much.
MelMeasure your output in smiles per board foot.
Mel,I just started dressing my stones with the diamond because I liked the way they cut after flattening them. I don't remember when I started leaving the slurry on the stones but it was an accident the first time after being distracted by a phone call. I haven't really tried diamond stones exclusively for sharpening. They don't seem to hold up very well in steel. I'm not sure if the diamonds in a DMT stone are mounted in the same binding matrix as in our metal shop diamond grinding wheels but it looks the same. I have talked with the tech people from the company who makes the diamond grinding wheels I use. They advised me to expect a short life from my grinding wheels in steel because grinding swarf from steel is stringy and wears away the matrix. The tech guy said the grinding wheels were intended for very hard things like carbide or stone where the grinding swarf is granular.I don't have any real experience with ceramic stones. My partner, Don McConnell, tried them and said he thought they tended to load up over time. He also spoke to Wayne Barton a few years ago about the Barton stones and tells me those stones have been through a special polishing process. I don't really know anything more.I can't really say if the Arkansas cuts coarser with the slurry or after dressing. If it does, there isn't a lot of difference. I do know that my aluminum oxide grinding wheels are more aggressive after being dressed with a single point diamond dresser than after dressing with matrix mounted rectangular diamond dresser. There could be several reasons for this, I haven't spent much time thinking about it. I just use the single point dresser.I've never used a Tormek. I once watched a demo at a show and felt it looked slow and full of paraphernalia. It's not something I find attractive. I do have plenty of experience sharpening-worked as a finish carpenter/cabinet maker using a lot of hand tools for more than twenty years and have made more than a thousand planes (don't know how many more, I quit counting a number of years ago). We make, heat treat, flatten and sharpen our own irons so most of the irons we sharpen are fresh from heat treating and need a lot of work just to remove the initial distortion. We're always looking for a faster way to flatten and sharpen but have tried nearly everything people talk about on woodworking forums.
Edited 5/31/2007 9:35 pm by lwilliams
Larry, as you say, diamond wheels do not grind steel well. This is because they glaze over and build up heat. The diamond wheel must only be applied to the carbide portion of the tooth , cutter or planer knife. If you deal with Leitz tooling they give exact details of what grade of diamond wheel to use for the relevant cutter and which stone wheel for dressing back the steel backing.I have observed first hand in a factory what happens to these wheels when an operator was in the habit of grinding both at once. Leitz is the company that I have experience with.
Those diamond plates such as DMT produce are not affected in the same way as diamond wheels: they are fine for both carbide and steel (and many other things). I am not sure but I would presume that the matrix and or the grade of diamond are quite different.
I have always used kerosene on these DMT plates, without any adverse effects at all-seems to promote a better cutting action .
"We make, heat treat, flatten and sharpen our own irons so most of the irons we sharpen are fresh from heat treating and need a lot of work just to remove the initial distortion"---- Are you talking of O1 steel here and what means are you using to flatten after heat treatment? (If not a surface grinder?)Philip Marcou
Phillip,My experience with the DMT stones is that they don't last very long when sharpening steel. They do well when maintaining oil stones.Yes, we use O-1 but we don't use a surface grinder. A manual surface grinder isn't the fastest machine around and a CNC grinder wouldn't pay for itself. Using only enough pressure to get a bite, we lap the distortion out using 80 grit SC paper glued to granite. From there I hone out the abrasive signatures and dubbing on the medium India. Well, that's the way I do it. We've all developed slightly different techniques. We've tried a number of different methods but keep returning to the 80 grit SC paper. A surface grinder would require a lot of fixturing. Some irons have a double taper others have curves machined into their backs and the variety and size range is pretty significant. Even with the necessary fixtures and a CNC surface grinder the manual changing and loading of fixtures would make it slower than just manually lapping the irons.We are well aware we're fighting the same labor intensive production that early wooden plane makers struggled with. By the mid 19th Century most wooden plane makers were making a lot of compromises to cut labor costs. So much so that planes made under those compromises were poor imitations of earlier planes. I'm convinced wooden plane makers contributed to their own demise by cutting quality. We have moved some of the production to machines and are working on more but we intend to avoid the mistakes of the late 19th and 20th Century.
im going through flattening the backs of all my tools right now. man what a pain in the ####. ive been using metal sanding paper, but it wears out very quickly and keep having to change paper at 80 grit. i have a very unflat chisel back and plane iron, so i have mucho sanding to do. how well does wet/dry paper stand up to this task? lets say 120 grit to 1000...would i have to be changing paper as often or will the water help keep the paper unclogged and possibly lengthen the life of the paper. anyone?
ive been using metal sanding paper, but it wears out very quickly and keep having to change paper at 80 grit.
Go and get yourself a couple of blue Zirconion Oxide belts from a belt sander (80 and 120 grit available). Glue them to glass. These will outlast anything else.
Regards from Perth
Derek
would you suggest i use 220-1000 wet/dry sandpaper after the 120 belt sander belt?
would you suggest i use 220-1000 wet/dry sandpaper after the 120 belt sander belt?
Yes. Have a look at an earlier post of mine in this thread for a link to an article on this sequence.
Regards from Perth
Derek
Larry
On DMT's site and on the package for a DMT stone it say's use only water for a lubricant? Will oil hurt these stones? I assume your using oil on the oil stones as you true them?
I've used WD-40 on mine for a long time but I don't know what DMT would say about that. There used to be a quite knowledgeable woman from DMT who frequented some of the woodworking forums. I don't recall seeing any of her posts for a few years. You might contact them and see what they say.
Larry
I looked at the DMT site a little closer and they do say that WD40, kerosene and mineral oil will not hurt the stones.
A local glass shop might have scrap or broken (sometimes called used) plate glass from commercial installations, 0.250" works nicely on the top of a table saw.Leon
Hi, Lyptus -
Late with this - my 2 cents on chisel sharpening & flattening, and ease of acquiring float glass is here - see scary sharp link. Hope it helps a little. Send EMail if you care to discuss.
Best of luck - - John
I have a couple opinions:
I'm with the fellow who said just get a piece of glass and some sandpaper (sorry I forgot your name). Derek is right, but I think he's getting edges you may not need. He lives in Australia where wood is made of iron with bits of carbide thrown in. I live just outside Philadephia and wood here is soft and easy to work.
I tried my friend Paul's 220 grit shapton. I liked it. It felt like 220 grit SiC paper or maybe even a little faster. But even Shaptons require flattening. For a coarse stone, (and for back flattening) I think you'd do just as well with paper because you don't have to worry about flattening it. I'm using Corian as a plate and its flat enough. Guys talk about using super flat surface plates, but one wonders exactly how flat a used Shapton is. I just don't think its that big an issue.
At the end of the day, all you need is for that back to be smooth. There's nothing in the woodworking rule book that says blades must have flat backs. There are advantages to flat backs, primarily having to do with sharpening. In use, kinfe edged chisels work fine or better and kinfe edged plane irons may be advantageous (function like back bevels).
Sorry. Forget the physics. Just get some coarse paper and try it. You'll be fine.
Adam
Yu got a lot of good advice here so far.
I'm a disciple of the scarey sharp (sandpaper methodology) and about all I can add is that the flattening of the back that you seem to be worried about may perhaps come to yer attention via folks who are rehabilitation Old chisels, which may have rust pits in the back, Yer two cherries chisels ain't gonna have them, so you don't have to go to too much extreme to sharpen them. I'd be thinkin that trying to flatten the backs of em with a 220 grit stone may just be a retro thing, cause to my way of thinkin, they is likely flattened with a finer grit that that.
On the job-site, I'll use anything that resembles a flat surface to lay my sandpaper on (I carry a few sheets of various grits-up to about 600) in one of my toolboxes). A sheet of MDF, a sink cut out, you name it and as long as it's functionally flat, I ain't bin disappointed in terms of obtaining a functional edge.
OTOH, if -as a neophyte-yer lookin for the ultimate edge, can I be so bold as to suggest to you that there is nothing in any woodworkers literature which I have read in the past 30 years to suggest that you have to achieve that "nirvana" right now. In fact it may be time wasted, provided you get achieve a level of workable sharpness. A real sharp edge chips easily, and if you ain't used to the level of paranoia required to protect that edge, yer gonna learn the hard way, and waste a lot of time along the way.
Many times have I been rehabbing old chisels and plane blades and just had to say " that's good enuf for now" realizing that they next time they entered the sharpening cycle, that I could take it a little further along the way.
BTW, Yu didn't ask about buffing wheels and polishing compounds(use a light touch) or leather strops. Them will take you a little further down the slippery slope.
Eric in Cowtown
all I can add is that the flattening of the back that you seem to be worried about may perhaps come to yer attention via folks who are rehabilitation Old chisels, which may have rust pits in the back, Yer two cherries chisels ain't gonna have them, so you don't have to go to too much extreme to sharpen them.
Cowtown
The Two Cherries are among the WORST examples of manufacturers polishing up steel to look nice, and in the process rounding the backs of the blades. You are better off buying their cheaper versions, which are not polished. The steel is excellent and they hold a good edge, but they do not have paring in mind when they produce them for sale.
Regards from Perth
Derek
I couldn't agree more Derek. I once spent 2 hours flattening the backs of 2 Crown 3/8" chisels that I picked up "cheap" to make skew chisels to find that the nice polishing job they had done had seriously rounded the edges which meant that the apex of the skew was rounded. It seems not to be mentioned much but a sharp chisel is the intersection of 4 surfaces - the bezel, the back and the 2 sides.
It seems not to be mentioned much but a sharp chisel is the intersection of 4 surfaces - the bezel, the back and the 2 sides.
Hi Geoff
I like that definition - very much!
Regards from Perth
Derek
It seems not to be mentioned much but a sharp chisel is the intersection of 4 surfaces - the bezel, the back and the 2 sides.
Yeah, but...I think that while ultimately true, practically this can be taken too far. At least for me. I for one do not like--will not have--the arrises no where near as sharp as they can get. I hold chisels too often by the blade, especailly long paring chisels. I can cut myself easily enough at the cutting edge, I don't need to help it out by having the sides sharp as well.
As for the mentioned skew chisels, well, I could care less about the dubbing on my Crown. I have a few cranked skew chisels, one Crown as well as a couple Henry Taylors. The Crown was/is so polished that the edges are dubbed, the HTs not so much. But for what I use them for it is not an issue.
A couple straight skews I have made from "regular" firmers ended up with sharp arrises which I promptly knocked back a little with sandpaper.
Exactly zero of my vintage Butcher et al firmers [and other types of chisels] I have picked up had sharp side arrises...why would that be? Seems that to people in the past this issue of sharp side arrises wasn't a big deal. I suspect they made furniture much faster than I can. Probably much better as well.
Take care, Mike--the contrarian...
Mike, I don't think you are being 'a contrarian' but rather you illuminated the difference between the theoretical and the practical. Your statement that 'for what I use them for is not an issue' is applicable in my case in the majority of situations but with the skew chisels I was making them for cleaning up the lapped dovetails on my draws. You raised a point about the practices of people in the past and it amuses me sometimes to ponder what they would have made of all our modern jigs, various types of sharpening stones etcetera... PS If anyone out there has any of the LN skew chisels do they have sharp side edges - just curious.
Edited 5/20/2007 11:45 am ET by geoff7325
Ha--that's probably because I don't necessarily subscribe to perfectly flattened backs either but wisely avoided mentioning it <g>.
I handled the LN chisels last weekend at the LN Hand Tool Event outside of Portland, Ore. I would describe the ones I handled as "crispy" not sharp. Which is what I do with mine.
Seriously, Geoff, you do nice work from what I can see in the picture showing your HB'd drawer. Very nice. I mentioned to Deneb from LN at the show that it's been what seems like several years since I have done HB DTs and probably would mess them up--he tried to reassure me it's no big deal, but I don't think he's seen my through DTs <g>.
When I have done them, I use a single-bevel fishtail carving tool. Though I use to use handed-skews.
Take care, Mikeback to my flood of emails...
Derek, I was talking bout rust PITS in the context of rehabbing chisels, not rounding over from over polishing. Methinks you may have misunderstood. Eric
Derek, I was talking bout rust PITS in the context of rehabbing chisels, not rounding over from over polishing. Methinks you may have misunderstood.
Eric
That I did... My mind was still on the original topic, of flattening chisel backs.
Regards from Perth
Derek
Allow me to insert my two cents into this discussion. The back of a chisel should be flat all the way from tip to tang. Otherwise you leave a small hump that will elevate the chisel which will create a small bevel at the tip when re-flattening later. Once the back is flat, it should never need to be flattened again. From that point on, all sharpening should be to the bevel side of the chisel. Think of a traditional Japanese knife that is beveled only on one side. If you touch the flat side, you will destroy the knife. The geometry of a chisel (and plane irons) should be the same as the Japanese knife, only the bevel angles are different. The flat side of the chisel, should be applied to the sharpening stone only to remove the "whiskers". If you have the resources, take your chisels to a machine shop that has a surface grinder and have them grind the backs perfectly flat. It only takes a couple-a-minutes for each chisel. A final polish with jewelers rouge and the chisel backs will be perfect.
With all due respect, I think obtaining "perfectly flat" backs on chisels is not only unnecessary, but in some cases not possible. It isn't necessary for such a thing to be done...but hey, your dime and time.
There is such a thing as flat enough. I agree with Adam that polished is a great goal as far as being able to obtain a good sharp edge.
Take care, Mike
I'd go a step further, Mike. I think guys don't understand how chisels work. They think they can take a consistent shaving by putting the chisel flat on a surface. Chisels submarine. Moxon talked about this in 1680. A dubbed back actually helps you take a consistent shaving. The principle problem with a rounded edge isn't poor cutting performance or even difficulty in honing-those are both probably improved; the problem is that you can easily lose track of what the real cutting angle is. The ground bezel angle will be lower than the actual angle at the edge. What I see in really old tools are really low grind angles- like 20 degrees. I asked Leonard Lee if this was his experience and the reason why he invented a jig that essentially imitated it (and made the whole process easier). He saw the same thing but didn't agree the micro-bezel was new, but I think he's just modest. He figured this all out long ago. I think its interesting to note that David Charlesworth is dubbing his backs with his ruler trick. I don't know if this is new to him personally. I just get the sense these experts are leaning more and more to the rounded edges I see on early tools.Adam
PS I flattened all of my chisels to the bolster. That's where I am on the understanding foodchain. DC is way out front.
Hi Adam,
I suppose one could say my chisels *eventually* are flattened over a significant (defined as an inch or two) portion from routinely sharpening them. Perhaps by the time I am buried it will be over a larger portion.
I keep a flat portion on a chisel to aid me in sharpening in part. Only on a couple types do I care how much care is shown in the heat of work that this is maintained. My bench chisels would be considered non-flat by many/most people. It is the bench chisels that I use for things where registering and maintaining a flat reference isn't necessary. Heck, sometimes they might just as well be termed carving chisels.
Paring chisels, and for whatever reason my mortise chisels, are flat over the portion I expect to register to a line in its departure down from a scribed line.
fwiw, DC only uses the ruler trick on plane blades. Chisels are flat-backed for a length of I don't know how much. I've spoke with him once and I would love to meet him one day and pick his brain, work alongside him. You're on that list as well...and Chris...and Don...and...
Take care, Mike
Adam --I agree flat backs don't make a chisel cut a flat, as you say they submarine. One thing I keep thinking about is paring bevel down. Kind of flies in the face of the back acting as a "fence" doesn't it! I often pare bevel down and ride my bevels. I don't hollow grind, my bevels are what most would call round. So, if one can pare bevel down with a rounded bevel, how important is a dead flat back?-Dean
Edited 5/30/2007 10:10 am ET by deanj
I thought I read somewhere that paring chisels were often double beveled. Was that in.....anyone?...anyone?...Bueller? Moxon?
Adam
Adam,
Carving chisels are typically bevelled on both faces. Perhaps that's what you were thinking of?
If I am paring, I am taking a very light shaving off the stock I am attempting to flatten. If I am careful, there is no tendency to "submarine". I pare with bevel up. In paring things like dovetail pins flush to a surface, the "flat" side of the blade registers against, and rides over, the flat surface I am paring flush to. Truing up a surface, like forming a flat on the shaft of a tripod table for a leg with sliding dovetail to mate to, takes a little finesse, but the same idea applies. Index the back of the blade onto the portion of the surface you want to extend, and take light shavings off til you are there. Hard for me to get anything better than a subtly rippled surface with bevel down, sorta like the background around a relief carving, it looks flat, but it's not really flat.
Ray
Ray
"Carving chisels are typically bevelled on both faces. Perhaps that's what you were thinking of?'No. See Plate 12, Figure 11 "Le Menuisier En Batiment" Can anyone interpret the text for this double beveled chisel looking thing? Page 60.
Ray,I think someone interpreted this text and found this (double beveled like a carving tool) was the preferred shape for paring chisels. If I'm not mistaken, this is also the medieval form of the tool.----
So if any of this is true, it would suggest a different technique (obviously) than that Ray described. Additionally (and to the point here) it suggests that not all chisels need flat backs to function. I guess we don't need dead frenchmen to convince us of that. But I suspect folks would be shocked to learn exactly how useful "dubbed" chisels can be. My inference is that someone went way too far in their suggestion that chisels and plane irons must have flat backs to function. They most certainly do not and this may not even be the traditional form of such tools.Or I could be wrong! I think by the close of the 18th c, firmers and paring chisels were virtually indistinguishable. On the otheer hand, if I'm right, we now have justification to go out and buy another full set of chisels!Adam
Edited 5/30/2007 9:11 pm ET by AdamCherubini
The reason why I advocate perfectly flat backs is because that's the way the chisel was manufactured. Using and regrinding a chisel rounds the edge to the point where the geometry of the chisel is all wrong and only serious grinding can restore the edge. As I said before, all grinding should take place on the bevel edge only. The only time the back meets the stone is to remove the whiskers. This has to be done very carefully to avoid rounding the edge.
seatoe,
I also subscribe to the same method as do you. But I'm just a persnikerty old fart and I like all my irons that way. It's probably just me but I'm more confortable when it comes to honing the bevel if I know the backs are flat.
I'm also surious to know if it makes any difference as to the bedding of the iron in the plane?
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
"The reason why I advocate perfectly flat backs is because that's the way the chisel was manufactured."
Uh, I don't believe this is necessarily so. And when it *may* have actually happened on X number of chisels from the same manufacturer, it was as much a planned accident as anything.
I've had too many NOS Stanley 750s et al in here for flatten the backs for various customers to believe this "manufactured flat" thing.
I have had more than one or two vintage chisels made from the early 1800s on up and *might* have had a couple with relatively flat backs. But never "perfectly" flat backs. Certainly not as flat as "proper" milling would afford. I have had more than one or two new chisels in my possession since the 1970s and I can also say their backs ranged from poor to OK (in my view of OK) to relatively flat.
Recommending people have their chisels milled flat is simply silly in regards to actually using chisels. It's unnecessary. But, like I mentioned, if one chooses to take a chisel to the nth degree of flatness, it's their nickel.
fwiw, even flattening (to the degree I care about) is a process which can occur over time. As well, it is nigh unto impossible to have a paring chisel with a so-called "perfectly" flat back...and because they flex along their length in use (a desirable attribute) "perfectly" flat is nearly meaningless.
I'm not sure what you mean by:
"Using and regrinding a chisel rounds the edge to the point where the geometry of the chisel is all wrong and only serious grinding can restore the edge."
But if you mean that using a chisel (or any edge tool) creates what is a wear bevel on the back of said tool, then yep, it does. I wouldn't call the needed sharpening or honing "serious" grinding, though. I don't know about you, but I keep a stone on my bench and very frequently hone between minor operations. Just a swipe or two (or three but you get the idea) is what it takes to keep a chisel edge sharp. On my plane blades, I take them to a greater point of edge failure...except my smoothers. Smoothers I tend to keep honed.
But I suspect you are equating "regrinding" an edge to rounding, or dubbing. Gotta say I haven't experienced that.
Take care, Mike
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