A Primer for Handcut Mortice-and-Tenon Joints. Part 1: The Blind Joint

[Derek Cohen]

Below is a link to an article I have just placed on my website: http://www.inthewoodshop.com/Furniture/AHandcutMorticeandTenonPrimer-BlindMortice.html

http://www.inthewoodshop.com/Furniture/AHandcutMorticeandTenonPrimer-BlindMortice_html_m19979e6d.jpg

As always I am open to ideas for changes in these articles. Anyway, I'd love to read about your techniques here as well.

Regards from Perth

Derek (struggling with a cold for the past 10 days)

[Martin Peek]

Great primer. The pictures are very informative. Feel better soon.

[Michael Schwartz]

great artical

Any source for the Kinshiro morticing gauge? I am intrigued how it has two opposing router plane like blades, never seen this before.

[Russ Massery]

Great tutorial Derek! I have always found your website tutorials very informative.

Russ

[Derek Cohen]

great artical

Any source for the Kinshiro morticing gauge? I am intrigued how it has two opposing router plane like blades, never seen this before.

Hi Michael

Mine was a gift ... a very generous gift.

You can get expensive ones here: http://japantool-iida.com/index.html
.. and less so here: http://www.dilegnosupply.com/Marking-Measuring/gauges_japanese_marking_gauges.htm

Regards from Perth

Derek

[Ron Petley]

Wow, thanks for a slice of your wood working world. Very inspiring.
With your skill you make it look easy. Nice of you to ass the part about fixing things if things go off the rails, a imortant part for me when I go to try this. :)
Cheers Ron.

[David Gendron]

Great work Dere, realy anjoy that it's realy helpfull. It's allways nice to have some one ways of doing things... Never thought to write a book?

[Michael Panis]

Very helpful. Thanks!

---Mike

[Rob Fisher]

Derek,

Awesome article, THANKS!
In the article you stated that the mortise chisels have a primary bevel of 20 deg and a secondary bevel of 35 deg. What is the rational for these angles?

Thanks,
Rob

[Chris Gilly]

Great stuff, can't wait to read more!

[David Keller NC]

Very nice, Derek. I do things a bit differently on the execution of the joint, but what you've described is perfectly fine for a tutorial - describing 15 different ways to execute a joint is, in my opinion, a detraction from the purpose, which is to offer a clear method from start to finish.

One sideline that might be worth adressing, however, is in the layout. I often use the method you cite for laying out the tenon shoulder, which requires that the end be dang near perfectly square in both directions to the face and edges of the rail.

However, I've come to realize after taking apart a few (very old) antiques that's not the only way to do it solely with hand tools. In particular, I noticed on quite a few of these that the tenon ends were rough-sawn, and far from perpendicular, square, or smooth. In one case, the rough marks of a coarse cross-cut saw were clearly in evidence on the end grain.

I suspect these gents laid out their tenons by measuring the shoulder-to-shoulder lengths of the rail, then marking out the tenon soulders with a square. This makes the layout marks entirely independent of the ends of the board, and even the overall length of the board.

I'm speculating here, but this makes sense if you think about the rarity of metal miter planes in this era. Planing end grain is always harder than face or edge grain, and while I suppose it can be done with a strike-block plane, I suspect these planes were relatively rare based on the antique tool market. So in the absence of a wooden miter plane, it makes sense to measure out the length of the rail from shoulder-to-shoulder and avoid having to plane the end grain all together. I recently tried this technique out in the workshop, and I can say that it works beautifully if you have a self-standing folding rule, but not so well with a modern tape measure.

[Derek Cohen]

However, I've come to realize after taking apart a few (very old) antiques that's not the only way to do it solely with hand tools. In particular, I noticed on quite a few of these that the tenon ends were rough-sawn, and far from perpendicular, square, or smooth. In one case, the rough marks of a coarse cross-cut saw were clearly in evidence on the end grain.

I suspect these gents laid out their tenons by measuring the shoulder-to-shoulder lengths of the rail, then marking out the tenon soulders with a square. This makes the layout marks entirely independent of the ends of the board, and even the overall length of the board.

Hi David

Very good point!

I totally agree with your reasoning. I could have concentrated more on 'how the lengths are created in the first place' and tended to gloss over this to the joints, per se.

If I was marking up in multiples, it makes sense to use a large carpenters square to mark the shoulder lines. Those are the only ones that really need to be done with precision. No one will see the end of the tenons, and they are not important for glueing up.

What I have offered in probably more in keeping with the way we build our one-offs in our well-equiped workshops.

Regards from Perth

Derek

[Jack Camillo]

Thanks, Derek,
jack

[Thomas Kila]

Great tutorial, Derek. I know I am one of many who appreciate the advice you share so freely.

Mahalo,
Earl

[Kent A Bathurst]

Excellent information. Recently got the LN large router plane, and this helps my understanding.

If you are running a contest for "dumbest" responder, please put my name in the hat. I had never realized that big opening in my shoulder plane could be used to pull the plane toward me.

[Jon Toebbe]

In the article you stated that the mortise chisels have a primary bevel of 20 deg and a secondary bevel of 35 deg. What is the rational for these angles?
A 20 deg primary bevel allows the chisel to penetrate more easily/deeply when you give it a good whack with a mallet. The 35 deg secondary is to keep you from destroying the edge when you beat on the chisel with said mallet. ;)

I was originally very disappointed with my MHG mortise chisel. The durn thing developed a snaggle-toothed, chipped edge after just one, shallow mortise... because it had a 25 deg bevel. :o A little work with the grinder, some more sharpening, and a nice, fat 35 deg secondary bevel and that little problem disappeared. As the ham radio folks like to say: the short was between the headphones.

[Jacob Griffith]

Great work...thanks for posting.

[Kirk Poore]

Derek:

Nice, clear work. The only thing I would add are a couple of checks:

1. Veryify that all rails are the same length after the shoulders are cut. A few times I've found that cleanup has made one or another a little short.

2. Make sure that the rails are perpendicular to the stiles when fitting the joints. As in (1), sometimes the cleanup process can leave the shoulder at an angle.

Kirk

[Derek Cohen]

Hi Kirk

Good points.

There are a few others that others have made. When I get a chance I shall add them to the article.

Regards from Perth

Derek

[Cullen Parish]

Excellent write up, thanks.