Chopping mortises-perpendicular

Re: To pare or not to pare mortise sidewalls *LINK*

Don McConnell

>Hi Wiley,

As you may have noticed, I had deliberately stayed away from the issue of chopping vs. paring mortises in my previous responses. While the two issues may have some points of contact, I felt it best to treat the non-gap-filling characteristic of hide glue as a discrete topic.

When it comes to cabinet/furniture scale mortise and tenon joinery, my overwhelming preference is to use the appropriate width mortise chisel and let it determine the width of the mortise by chopping straight-away. In addition, I've become a relatively recent convert to the method described some years ago by Jack Maynard; first brought to my attention by Bugbear (see link), and recently written about by Chris Schwarz in an article comparing methods of chopping mortises. While this approach involves a little more chisel manipulation than some others, in my experience it results in cleaner mortise walls as well as a more consistent/predictable width.

Moxon's _Mechanick Exercises_ sheds a good deal of light on late seventeenth century woodworking practices, and I refer to it with some regularity. But, it is best to keep in mind that it is one man's observations, and may not be completely representative or accurate. Among other things, his description of mortising may reflect practices relevant to larger scale mortises than those in typical cabinet/furniture work, today.

Don McConnell

Eureka Springs, AR


http://nika.frontier.iarc.uaf.edu/~cswingle/archiv

Re: To pare or not to pare mortise sidewalls

Joel

>You bring out an important point:

Does Moxon's instructions have any real relavance to actual CABINETMAKER's practice in the 17th century?

This of course raises a bunch of questions:

Who wrote the book?

We know some of the illustrations were copied from the French, I don't think the text was. Moxon was a successfull printer/publisher who in the building boom of post fire London would have seen a market for a how to book on woodworking. But who was his audience? Curious gentleman like Pepys (who was a customer) who were interested but couldn't tell if Moxon was right or wrong. OR actual tradesman. Of the latter I doubt. Who wrote the book? did Moxon himself interview craftsman and try to put together a coherent account (my guess is yes) or is this the work of some anon? I don't think the answer is definitly known at all - but I could be wrong.

As for the specfic mortising insturciton, Moxon does include it in his section on joinery as opposed to housebuilding but it should be understood that "joinery" at that time also included finish carpentry and anywhere where a plane was used. The mortise he describes is 1" wide - too wide for furniture but also usually too wide for the mortise chisels he describes using - they exist in early catalogs at that size but are extrelemy rare - don't know I if have ever heard of one in actual existance - also at that size it is faster to just pre-bore.

And of course certainly the practice Moxon described might have been local to that area of London, that time-period etc. we don't have enough data to really know. But I can say with certainly - from actual practice, that while many other methods of mortise exist following Moxon is the fastest method I personally know of.

Re: To pare or not to pare mortise sidewalls

Pam Niedermayer - Austin, TX

>I find I get superior fits if I chop the mortise at the chisel size, which measurement is then used to mark the tenon (or vice versa, doesn't really matter). I saw the tenon barely on the line to the waste side. If any adjustments need to be made, I make them on the tenon with a plane or chisel; but this, too, results in lots of wasted time fitting and paring, repeat ad nauseum.

When I start paring a mortise, I never know when to stop, sort of like pruning a bush, which normally results in a stub.

Pam

Re: To pare or not to pare mortise sidewalls

Wiley Horne--Glendora, CA

>Don,

Thank you VERY much for a detailed and thoughtful post. That thread that Bugbear started surely belongs on the OLDTOOLS list of classic threads.

As it happens, Odate's method is the one I evolved to, without knowing it was the Japanese method. It just seemed that the first thing to do is make that V pretty much to full depth, in order to cut away the lateral support from the rest of the wood in the hole. From there, it's a downhill pull.

Your own contribution is much appreciated, too, to get that V located exactly plumb. The method is so effective, that it's a temptation to get going too fast.

One thing I have found while using this method may go against the prevailing wisdom. The method works best for me if the bevel is kept acute--mine are at about 27-28 degrees. This is a preference for getting the best depth with each lick, rather than favoring chip ejection. Others may prefer a steeper bevel.

Thanks again! Wiley

Re: To pare or not to pare mortise sidewalls

ThomD

>Shoji mortices don't require a lot of depth. As you point out, Wiley, the angle creates a definite limit as to how deep one can go, or an aspect ratio. The japanese angle is closer to 30-35 degrees, from what I recall. When I have to go really deep by hand as when morticing through a wide stretcher for a wedge, I usually break out the extra long record chisels, and probably drill out the waste. I saw a Japanese cabinetmaker on Modern Masters, and he was using a brace and bit to drill out waste, then he chiselled in what looked like the same way Odate does.

Re: pare or not pare

Moses Yoder in White Pigeon, MI

>People have not really changed that much in the last 400 years. So I would agree that just because there was a book written a few hundred years back on how to chop a mortice does not mean that everyone was chopping mortices exactly the same way.

I personally have never chopped a mortice by hand just because I don't have a chisel set up to use for that purpose yet. It seems like whenever I have a project that needs mortices I am always dealing with a deadline that does not allow room for learning and experimentation. So 2006 is probably the first time I'll chop a mortice by hand. It is intersting to have different methods described, to study and try out. After trying various methods I can develop a process that works for me.

Paring sidewalls - trade comment

Andrew F in Australia

>Hi All,

I've just had a skim read through alot of these posts and was intrigued by the article Don mentioned. I used to work with an old tradesman that was trained at Shoreditch. He was excellent and very thorough.

I was trained by two tradesmen who used two different methods.

The old skilled German tradesman used a 4mm chisel to rough out waste IF we had to hand chop a mortice. He then pared the sides clean.

The Australian tradesman just used a mortise chisel the same width as the mortice.

Both were equally as quick, and fairly easy.

I'm happy to pare the sides of a mortice if I need to to square up a joint - nobody's mentioned this as far as I can see.

Cheers,

Andrew

[I chop out a mortice by setting a chisel (a firmer, bevelled edge or mortise chisel - the same width as the mortice) at right angles to the layout lines and about 1/8" inside the lines, lightly chop the first couple of passes to define the cheeks of the mortice and then progressively take bigger swings at the chisel until I hit depth once there's something there to guide the chisel. But I usually use a slot mortiser - they're quicker

The main advantage to the mortise chisel is that you can cut the mortice quicker - try cutting a mortice with a 1/4" bevelled edge chisel and a mortice chisel of the same width. It takes about two - three times as long with a bevelled edge chisel.]

You've bolstered your view point!

Derek

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