Bevel angle for Koyamaichi paring chisels?

[sjalloq]

Hi,

hopefully simple question but having no experience with Japanese chisels I thought I'd check.

I recently bought a few of the paring chisels from Tools From Japan and they seem to have been ground at 32.5 degrees. Is there any reason I shouldn't grind them at the norm of 25 degrees for a paring chisel? Is there something about the white steel lamination that means 32.5 is the minimum, perhaps due to its brttleness?

Cheers.

 

[David C]

Yes, the very hard steel is much more brittle than ours.

Of course timbers worked also vary enormously.

I grind at 27ish, get wire edge on 800 stone at 30 degrees and polish at 32 degrees.

I have always felt sharpness was far more important than angle !

David Charlesworth

 

[custard]

I've tried Japanese chisels and as David says, they're prone to chipping in hardwoods unless the angle is that bit steeper. I also find the edge on A2 steel can get a crumbly unless you're up to about 30 degrees.

I keep a few carbon steel chisels that are honed at 20-25 degrees for working in softer woods, like some Rippled Sycamore drawer sides or some Swiss Pear, also I prefer skew or fishtail chisels for cleaning up dovetails to be at a lower angle, and most of my carving tools have just a single 20 degree bevel. I wouldn't want to belt any of them with a big mallet, but working with very low chisel angles can be a very pleasant experience.

 

[Derek Cohen (Perth Oz)]

Hi,

hopefully simple question but having no experience with Japanese chisels I thought I'd check.

I recently bought a few of the paring chisels from Tools From Japan and they seem to have been ground at 32.5 degrees. Is there any reason I shouldn't grind them at the norm of 25 degrees for a paring chisel? Is there something about the white steel lamination that means 32.5 is the minimum, perhaps due to its brttleness?

Cheers.

I suggest that you check with Stu at TFJ, however 32.5 degrees sounds unusually high for a Japanese slick (paring chisel).

My Koyamaichi dovetail chisels are 30 degrees, and they get hammered into hardwoods.

My Kiyohisa slicks are 25 degrees, and hold a superb edge.

Regards from Perth

Derek

 

[David C]

Recently I have become interested in the manner which people use paring chisels.

Are we talking about delicate slicing cuts? or full on straight cuts, where the only difference is push rather than tap/strike?

I mostly do the latter.

David

 

[Jacob]

I've used paring chisels mainly for trimming edges and/or arrisses when door fitting, and similar situations. It's the length which gives a narrow "aspect ratio", the shallow bevel angle means it will take off a thin paring with less chance of plunging, it's one handed whilst you are holding the door, and being a chisel you can trim right to the floor (which you can't do with a block plane).
Also use them for cleaning up tenons and other things - it's the length which gives you a more accurate controlled cut.
It follows that a short paring chisel is less useful and isn't strictly a "paring" chisel.

So the short one in the left isn't but the other two are:

 

[matthewwh]

There is a triangular relationship between grain structure, hardness and bevel angle, which Mr Koyama will have studied carefully and experimented with over many years. If he has supplied them with a given bevel angle I would recommend that you stick with it and focus your efforts on the quality of your polish.

25 is a good generic angle for western carbon steel chisels, hence you will find lots of recommendations for that. Japanese chisels however are a very different animal, both in terms of materials and mechanics.

I hope you will enjoy them, they are wonderful tools!

 

[Trafalgar]

As Jacob says, the point behind a shallow angle is control and to keep the chisel from diving. You can actually move the chisel fairly aggressively, by hand power of course, and still maintain control.

Use the shallowest angle you can. If you know how to hone a tool efficiently without all the drama, gear, and strutting and fretting edge longevity practically doesn't matter.

Here's another tip -- if one area of the edge chips, use another part of the chisel or pick up another chisel. Don't let it wreck your day or your worldview.

Best,

Charlie

 

[D_W]

In a light paring cut, sharpness rules. In a heavy paring cut, the shallowest bevel angle rules.

I had koyamaichi chisels, and I never noticed any inability of them (bench chisels) to hold their edge at the same bevel angle I have all of my chisels at (high 20s). I have less strong chisels that I use to mortise bench plane blanks (they are iyoroi - though ) that could do several large bench plane mortises and take very little in repair, they can one plane blank at a time with nothing more than a finish stone touch up- and at a lower angle than any other chisel that I have, which is why I use them - laziness. Economy of effort. Whatever you want to call it.

The one real life issue that I have with japanese chisels is that in heavy paring work that has the potential to abuse an edge (I guess malleting work, too), if the edges are abused and wear faster than the rest of the chisel, it's not as quick with a japanese chisel to sharpen that out as it is with a western chisel where you can grind most of it out.

I did have a koyamaichi blue steel parer at one point, and I don't think it took a back seat to anything, it certainly didn't need 32.5 degrees.

Though there's an obsession with having the entire bevel perfectly flat in a japanese chisel, if I had to choose for paring, I would hand grind the primary at 25 degrees and make the lightest kiss of a finish stone edge at a slightly higher angle if it was needed. I really don't like a big blunt steep primary bevel for paring cuts like one would make on tenons.

(I am now just using a trio of boxwood handled marples parers - real parers, not long bench chisels, and I believe they were marked chrome vanadium or something. They are better than blue handled chisels I had, but technically by no means close to the japanese parers I had. But they sharpen very fast and if they take damage, it's gone in two minutes).

 

[sjalloq]

Thanks for all the input here. I've tried to contact Stu in the past but his turn around in answering email means that I fire one off but also ask here. He might get back to me in 4 weeks or so depending on how busy he is.

I've ground them at the 27 degrees David suggested and will hone them at something higher. I'll experiment with exact angles and see how the edge holds up. I'm going to use these for cleanup jobs only. I have a couple of Isles bevel edge chisels I use for more aggressive work but I'm quite a noob at all this anyway. Will experiment and ask more...

 

[Derek Cohen (Perth Oz)]

Thanks for all the input here. I've tried to contact Stu in the past but his turn around in answering email means that I fire one off but also ask here. He might get back to me in 4 weeks or so depending on how busy he is.

I've ground them at the 27 degrees David suggested and will hone them at something higher. I'll experiment with exact angles and see how the edge holds up. I'm going to use these for cleanup jobs only. I have a couple of Isles bevel edge chisels I use for more aggressive work but I'm quite a noob at all this anyway. Will experiment and ask more...

Edge retention is partly about the steel involved and partly how the blade is used.

There is more stress on the bevel edge when taking thick compared to thin shavings. When I tested bench chisels in the past, I deliberated took 1/8" thick slices, using a mallet, in hardwood to determine how durable the edges were. That is the very opposite how one would use a paring chisel. With a paring chisel one is taking only whisper thin slices, and pushing the chisel - never using more force than that. The amount of stress on the edge is reduced to a minimum. This is the reason why one can get away with 15-20 degrees in some cases.

I think that ending up with around 30 degrees on a paring chisel defeats the reason for having one. A low bevel angle permits easier entry in the wood, and requires less effort to push. My recommendation, based on my own Japanese paring chisels, is to have a single bevel of 25 degrees. I really expect that this will be a good match. I would be most surprised if it were not.

Regards from Perth

Derek

p.s. Incidentally, those three chisels that Jacob posted are mine. Left to right - Blue Spruce, Witherby and Kiyohisa.

 

[Trafalgar]

The vintage Audels manual on woodworking tools has a fairly in-depth treatment on types of chisels and mentions that true parers (long and thin) were ground and honed around 15* I don't know if Japanese chisels would tolerate these sorts of angles.

FWIW, Ian Agrell hones his carving chisels with 10* inside and outside bevels. Might be instructive as some paring operations are as much carving as anything else.

http://www.agrellcarving.com/school/tip ... ol-tune-up

Has to be one of the top five carvers in the world.

Carved for the House of Commons in oak (photo is of the mock-ups):

http://www.agrellcarving.com/clients/house-commons

 

[D_W]

Very nice carving work - I would love to be able to do that type of work, but I haven't met many people who can do that and who aren't completely dedicated to it. You know who I'd mention as being capable of carving pretty much anything, but a lot of that has to do with the fact that he can take a blank space and actually design something that looks good (George).

There is a trade carver on SMC doing that level of work (Mark Yundt), and a lot of it, but there can't be too many people doing it - I guess I shouldn't forget Randall Rosenthal, whose page has architectural work of the highest order on it before he became specialized in the artistic carving he does. I think both of them said they just keep their tools sharp with buffers.

Hasluck's book says exactly the same thing about a back bevel on carving tools, though. Long thin primary and a secondary bevel on the back. All of my gouges are sharpened the same way, but I don't carve much - wish I was more prolific. It is the one thing where if you're going to do any volume of work, it will require significant monetary outlay in tools (but probably recoverable outlay - I haven't seen any good cheap carving tools).

Not sure about 15 degrees on a chisel, though. Especially with the quality of wood available to most of us (it's not uniform soft white pine or fine genuine mahogany). Half of my parers are set up to pare the insides of planes, and the bevels. the work on the insides is hard on a chisel set below 25 degrees.

 

[Cheshirechappie]

Just a thought on bevel angles for chisels generally - the oft quoted "grind at 25 degrees, hone at 30" will give a chisel that will pare most things quite adequately (if not perfectly). It'll also do pretty well for chopping work, too. As a starting point for a general purpose chisel made of most steels, experience over many years has led to these angles being about the best compromise.

Just because a chisel is generally reserved for work of a paring nature, it doesn't necessarily mean that a very shallow angle is necessary, or even in some cases desirable. The general purpose angles may well serve perfectly adequately. David Charlesworth is right - sharpness is more important than exact bevel angle.

Finding the 'perfect' compromise between edge strength and ease of cutting for any given chisel working a particular wood usually needs a bit of trial and error. Unless you plan to do a lot of such work, it's probably not worth the bother.

 

[D_W]

I would assume that someone who is going to do a lot of work would err on the side of shallower than that for parers. Only because all of the old texts I've seen mention something very shallow for parers, and probably because it affects the rate that you get work done (in thick pares to a joint line, a lower bevel angle beats sharpness any time - narrow wedge vs. wide wedge).

It probably doesn't matter much because nobody is producing anything at rate to make a living, and we can all choose an edge where the chisel doesn't chip at all - something that's better for most beginners.

 

[Jacob]

If you want to do "paring" cuts i.e. thin precise shavings using the chisel in place of a plane, then you need a shallow bevel angle 25º or less. Too steep and the blade will tend to plunge.