18thc chisels

Re: 18thc chisels

Christopher Schwarz

>Dean,

As always, you are thinking.

These Diderot chisels have a knife edge. The unbeveled side is slightly rounded up to meet the bevel of the tool. This seems to have little bearing on their effectiveness with light chopping. In fact, it reduces the tendency of the chisel to press back to the baseline of a dovetail joint (there is geometry involved that I won't go into).

However, I do like a flat back when paring one surface to another and am using the backs of the tool as a guide. These Diderot chisels won't cut exactly flush in my hands. Yet.

Chris

Re: 18thc chisels

Pam Niedermayer - Austin, TX

>Chris, are you talking about the Diderot? If so, he was a philosopher and encyclopedia writer, not a woodworker. Now his father, Didier, was a cutler, which sort of ties in with a knife type chisel.

Pam

Pam, the encyclopedia

VTAndy4

>contains illustrations of just about everything. Including chisels.

Chris, what's interesting to me

VTAndy4

>is that these chisels' width will actually get narrower the more they are ground. It makes me wonder if I'm being too dogmatic in my search for perfectly "imperial" chisel sizes. Maybe approximate widths are all that matters.

-Andy

Re: 18thc chisels

Greg Forster

>Will someone going to Colonial Williamsburg this month offer to take pictures of the chisels and perhaps get some feed-back from the Hayes' cabinet shop?

A chisel's back, in theory, should be absolutely flat as it functions like a plane bottom to control the cutting edge(for paring), but we're working wood here and as impressive as it sounds to discuss 0.0000... tolerances, it is unneeded "perfection"(for lack of a better word at the moment).

That being said, I have bought expensive, long paring chisels so distorted on the back, both along the length and side-side, they were unuseable without hours and hours of work to get them "flat enough".

Thanks, Greg

Re: 18thc chisels

Joel

>Chisels need to be flat just at the tip. If they are flat over the entire length of the back repeated sharpenings where the burr is chased back and forth will round the back. With a slightly hollow back - which traditional makers strove for, there is no problem with performance and repeated sharpenings just keep the back flat at the tip.

The idea that a chisel need to be flat from tip to bolster or even for an inch is a very recent idea in woodworking and probably persists because modern woodworkers don't really wear there chisels as much as previously but this could be why people regard edge retention as so important these days.

While as I said western chisels are supposed to be slighlty hollow - the Japanese have extended the idea of a hollow back even more and of course grind a very noticeable hollow in their tradition.

The early western firmer chisels were also ground so thin that there was even a little flex in the chisel so that you could "English" them as you worked. English style paring chisels of any quality as used by patternmakers are also intenially so thin that there is a little flexibility in the chisel.

Re: We don't need no stinkin' flat backs!

briarbrow

>Hi Mates, Don't mind my delurking. Curious though. What's the bother with having a fine grained high quality chisel ( true it is a broad term, a tool with many uses and classifications) at least those that need to be really sharp not having a flat back? At least, per Mr. Horne's comments, the first few mms(6 or so) behind the edge. At least you have a flat to sharpen to otherwise it'd never be as sharp as it could be, and maybe that little knob to ride on is a good thing.

Re: Chris, what's interesting to me

Andrew F in Australia

>Hi All,

Interesting point. I was trained by two different tradesman in how to chop a mortice. The German tradesman used an undersized chisel and then pared the mortise cheeks as the final task. This is the method you'd use with the chisel you describe - perhaps a throwback to the older tool design.

The Australian tradie used the typical British method of setting the width of the mortice to the mortising chisel and cutting in one swoop.

Both are equally as quick and produce a similar result.

Cheers,

Andrew

So over the course of using the chisel,

Bill Houghton, Sebastopol, CA

>you might have imperial, metric, Whitworth, and no-standard-at-all chisels.