Ray Iles Mortice Chisel Issue

[Steve Voigt]

Stanley, reading Kees' posts, I don't see any place he suggested that we should make do with subpar or defective tools. It seems to me he is saying that (1) actual width doesn't matter, because we size the tenon to the mortise, and (2) parallelism or uniformity is not necessary and may even be undesirable.

Anyway, this image may be of some interest to the discussion. It's a page from the Seaton toolchest book.

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I assume this is a nominal 3/8" chisel. We can see that it is trapezoidal in section, and that the width tapers pretty quickly from .400 to .350, and that no one cared about hitting precisely .375.

One of my favorite parts of the Seaton book is the discussion of the saws, and how the taper grinding is phenomenally accurate, despite the lack of precision machinery or even micrometers. It's obvious that the toolmakers of the time (1796) were capable of great precision; they presumably could have made things parallel or rectangular if they wanted to.

[Robert Engel]

Recently I decided to use them on a large project. Around 200 or so mortises for mortise and tenon work. Many of these are 1/4 inch wide mortises.

I'm a hand tool guy, but if this isn't a reason to buy a power mortiser, I don't know what is!!

[Kees Heiden]

Reading the sales blurb on the tools for working wood website about these chisels learns that they are trapezoidal on purpose. Grinding the sides square would have been a mistake. Producing this shape presented a major technical challenge. It's much harder then lasercutting some chisel shapes from a sheet of steel and slapping a handle on one end.

[Jim Koepke]

Reading the sales blurb on the tools for working wood website about these chisels learns that they are trapezoidal on purpose. Grinding the sides square would have been a mistake. Producing this shape presented a major technical challenge. It's much harder then lasercutting some chisel shapes from a sheet of steel and slapping a handle on one end.

I really do not want to get into a debate on this, but isn't there standard mortice/mortise chisels, with trapezoidal blade profiles and also 'registered' mortice chisels with sides square to the cutting edge?

My own preference is for the trapezoidal blade. The square sided chisels were a bit more difficult to pull out of the work.


jtk

[Stewie Simpson]

Early mortise chisels were tapered back in width and thickness for a good reason. By design it reduces the likelyhood the chisel blade will jam tightly within the confines of a deep mortise.

Stewie;

[Kees Heiden]

Sash mortisechisels were often square.

[lowell holmes]

Becksvoort, in a Fine Woodworking article, drilled the mortise with an auger bit. He then inserted a LN mortise chisel in the mortise at one end and levered the chisel down the mortise, cleaning out the sides, leaving a smooth sided mortise. I tried it and it worked really fast, with a clean mortise the result.

I don't know why, but I use the pig stickers to make my mortises, unless I use a bevel edged chisel for some reason. Paul Sellers taught me well in his classes I attended.

I guess the reason for this post is that I have different style mortise chisels and use them at times. I have posted photo's of chairs I built that have 1" square tenons on the front posts that are through mortised on the top of the arm. The mortises were chopped with a bevel edged chisel.

I have some firmer chisels I will use to chop a mortise if I happen to have a size handy that I'm looking for. I have never understood what a firmer chisel is except it is a square sided chisel with a blade thickness between that of a bevel edge and a mortise chisel.

On one occasion I needed a 15/16" mortise. It was a quick task of grinding a duplicate 1" bevel edge chisel to 15/16" and then chop the 15/16" mortise. If you chop mortises with bevel edge chisels, there really is no issue. I bet we all have bevel edges chisels we can modify to make the mortise we want.

[Warren Mickley]

Making mortises by hand is about precision, not accuracy. We set the gauge to the chisel and use it to mark the tenon and the mortise. That insures that the tenon and the shoulder match the mortise and the shoulder. If you measure a 1/4 inch shoulder for the tenon and measure a 5/16 width of the tenon and then measure a 1/4 shoulder for the mortise and 5/16 width for the mortise and hope this all matches the "5/16" chisel, you have five chances for error, a horrible mess. And if you drill holes rather than relying on the chisel for precision, there are more variables, a bigger mess.

In the 18th century they used fixed pin mortise gauges: a gauge for each mortise chisel. This not only saved the time for setting the mortise gauge, it helped precision. If you were consistently cutting the tenons too fat, you could use a fine file to slightly alter the gauge for better performance. In other words once you had a nice set up it was there for the next time.

In the Seaton chest mentioned by Steve there were eight mortise chisels of various sizes and all had taper in two directions. There were mortise gauges with multiple sets of pins, one set of pins to match each chisel. My sash mortise chisels taper slightly in two directions also. I can't see why they should not.

[David Dalzell]

I'm a hand tool guy, but if this isn't a reason to buy a power mortiser, I don't know what is!!

Well I do this for the pure enjoyment of working with wood. I am an amateur, I don't sell anything. What I build goes to my various family members. Hence, I am never under any kind of pressure to work fast. I haven't actually counted the number of mortises in this current piece. My 200 number was a guess. However when joining stretchers to legs, dividers to stretchers, etc. I usually use double M/T. Sometimes for the strength provided by the added glue surface and sometimes because a double M/T is required to fit a drawer runner to a stretcher and around the drawer divider. So I count the double M/T as two, not one joint. By the way, I also have eleven (11) drawers in this piece. No two are the same size, they differ in width, height or a combination of width/height. All of these will have hand cut dovetails. A lot of dovetails, but also a lot of fun.

[Kees Heiden]

That'll keep you from the streets for a while! Have fun.

[John Coloccia]

Personally, I wouldn't use a mortise chisel with straight sides. Put me firmly in the tapered sides camp. They're much more pleasant to use, IMHO.

But as to the OP, being .010" or more off in your metal work on something like this is really disappointing to be very honest, and .018" is ridiculous. I can see being off in length, or height, or actual cross section, or any number of other things but I don't think it's unreasonable to expect the width of a mortise chisel to be nailed far far better than what you have. I can do better than that just laying out with Dykem and eyeballing it. I would expect the width at the cutting edge to be within .001", and certainly no more than .002".

I know all the arguments for why it doesn't matter, take your measurements from here, etc etc. The fact is that these days most of us are "mixed" shops. Yeah, there are people that ONLY use hand tools, either because of space, or they don't like noise and dust, or cost, or whatever, but most of us that use hand tools do it in a shop that also uses power tools. Having to carry around these whacky measurements from tool to tool is maddening.

That's just my opinion.