Official Luthiers Forum!

Well?

I’m working on upping my sharpening game. I have a Tormek which does a pretty good job - wet stones can do better. I attended an interesting offering at the GAL conference on sharpening plane irons. Based on what I learned there, my skills have improved a bit - I guess another question would be what is your favorite chisel for cutting purflings?

Thanks, M

I have always sharpened my chisels with a 22.5 degree bevel and a small 30 degree microbevel. WhenI bought a Lee-Nielson chisel, it came with directions to sharpen with a 35 degree microbevel. I didn’t believe it, so I called and talked to them. They were serious, 35 degrees, and said that with the more acute angle the edge might crumble. So, I tried it. When I trim braces, I cut bevel down so I can control the depth of cut by the angle that I hold. The 35 degree microbevel seriously interfered with that method. So, I resharpened it to 30 degrees. The short answer, then, is I cut my purflings with a chisel sharpened with a 30 degree microbevel because that’s how all of my chisels are sharpened. When the micro bevel, starts getting wide, I redo the 22.5 degree bevel and start again. The chisels seem to cut better when the microbevel is small.

I use 3M psa papers on a flat granite block (I think this is often called “scarey-sharp.). And, the Lee-Nielson socket chisel was an experiment. I tend to use my Stanley Sweetheart socket chisels most of the time. They seem to hold an edge as well as the other brands I have tried. I like socket chisels because it’s easy to make a new handle to fit my style (I like ‘em long).

The only chisel I've used for cutting purfling is my LMI 14-mm chisel which has right around a 22 degree bevel. It gives nice clean straight cuts for miters and butt joints and is very controllable.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

We grind to 20 deg and hone to 25 deg on paring chisels for along-grain work, but most of the cuts on bindings are end-grain in tougher woods, so 25/30 ends up being more durable. No micro-bevel... just a clean grind on a CBN wheel and honed bevel... regrind when the bevel starts getting too wide.

Technique-wise, the bulk of the cut is saw work, with just the final trim cuts (last little bit of fitting both angles and length) being chisel work, so even the end-grain paring on ebony or rosewoods is not too tough on the blade.

Tool-wise, I still like my vintage 1970's octagonal-handled Two Cherries-branded 12mm and 20mm for most work, including fitting wood, fiber, and plastic purfling and binding. Mine are cut down a bit on length because my own unused - original Two Cherries chisels duplicate the two I used most often at Greenridge early on there, which turned out to be the first two chisels Mr. Stock bought back in the 1970's. Often daily use over 45 years had taken off well over an inch of blade versus stock length, so I committed a bit of hand tool sacrilege when I found my own set on Ebay and matched configuration with those shop favorites.

Marvelous how customary use of something like a chisel seems to make it fall to hand so much more easily than another, similar tool new to service.

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We have become a civilization that elevates idiots, prostitutes, and clowns. Am I still to defend it? Yes, for its principles. Yes, for what it was. Yes, for what it still may be.

-Mark Helprin, The Oceans and the Stars: A Sea Story, A War Story, A Love Story (A Novel)

I can barely even comprehend that kind of use. For me, that would be an honor even to hold a tool with such use. I have an 1879 Morgan silver dollar, worn half smooth, that I hold in that same regard.

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Measure Twice,

Karl Borum

For general purling trimming - I just want a good quality chisel honed very sharp. This is not particularly taxing work, but for clean cuts, sharp is a key factor.

Purfling miters often require sneaking into corners, I prefer a thin chisel with very fine lands to prevent bruising the purfling in the corner.

Luckily, the depth is very shallow.

If you have a chisel you already like, maybe a 1/4" wide or so... Grind the flats on the sides into side bevels that go all the way to the back. This will help sneak into those corners to cut the miters without bruising them.

Stuff you can buy:

One option I've seen is the X-acto chisel blade. These are throw away, but very thin.

Quality chisels you can buy retail which have extremely sharp lands that are handy for sneaking into corners: Blue spruce, Lie Nielsen, Woodcraft Socket, and Veritas.

Quality chisels you can buy retail which have thinner side bevels. These don't go all the way to zero, but are thinner than usual retail fare. Narex richter, Ashley Iles, Dictum.

Otherwise, just grind sharper side bevels on a spare chisel you like, and save it for this duty. If you don't want to spend a fortune, modify a current production hardware store Stanley or Buck Bro's and off you go.

Thanks.

So far as I can tell, the 'right' bevel angle depends a lot on the steel in the tool, and also the hardness of the wood you're cutting. I've had good luck on this job with a 1/4" chisel I made from a Nicholson 3-square (triangle) file. After almost fifty years of use it's down to a stub, and I'm in the process of making another. I guess Nicholson has declined a bit over time, but the old ones had steel that was both very hard and tough, which is tricky to do. Don't do any heat treating or you could lose the fine grain, which helps in holding an edge.

I think the question doesn't have a look-it-up-in-a-book answer, but one developed over time individually. Not too many rote shortcuts in art.

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Peter Havriluk

Most of my chisels are vintage, I have a variety of them that I have collected over the years. T.H. Witherby, Swan, A few old Stanelys. I sharpen all of them to 25 degree angle using different diamond plates and then up to 1200 wet or dry sandpaper on plate glass and then finally on a leather strop.

Every time I use one I touch up the edge after I am done using them so they always remain sharp. For very tight work I have a newer 1/4" Pfiel beveled edge short handled chisel that sharpens up really well but doesn't seem to hold an edge as long as most of my old chisels. But I like it because it fits perfectly in my palm.

When I touch them up I probably put a slight microbevel on them but I generally stick to 25 degrees.

Cheers,
Bob