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Forum topic by Bohaiboy posted 08-07-2017 12:39 AM 625 views 0 times favorited 4 replies Add to Favorites Watch
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Bohaiboy

71 posts in 1627 days


08-07-2017 12:39 AM

Happy Sunday afternoon to all. M&T question. I am joining a portion of a table apron (3/4” stock) x 5” tall, to a leg that is 1 3/4×1 3/4. The apron will be set back from the edge approx 1/8”. The length of the apron is approximately 20”. I have attached a drawing to illustrate what I mean by a portion.

What depth should I make the mortise? I am thinking 1”. And I am thinking the tenon should be 1/4” as that leaves 1/4” on either side vs making it 1/3 and only leaving 0.2083” for each shoulder. There will only be 3 1/2” of the apron against the leg.

-- Tim, Houston, TX area


4 replies so far

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Loren

9602 posts in 3481 days


#1 posted 08-07-2017 12:45 AM

While 1” is not unheard of, since it is a handmade
piece I would recommend going to a little more
effort and making the mortises intersect. The
tenon ends can be mitered or notched out to
meet in the intersecting mortises.

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TungOil

740 posts in 328 days


#2 posted 08-07-2017 12:46 AM

If I were making that I would use a 3/8” x 2-1/2” tenon and go as deep as possible without interfering with the adjacent tenon from the other apron.

-- The optimist says "the glass is half full". The pessimist says "the glass is half empty". The engineer says "the glass is twice as big as it needs to be"

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PPK

862 posts in 642 days


#3 posted 08-07-2017 03:33 PM

I agree with Loren. The traditional method is to make the mortises intersect.

I cheated a little and instead of mitering the tenons, I stuck one in full-length, then just chopped the other tenon to fit. It ended up a lap joint inside there. I really don’t think its hugely critical.

As concerns size, I’d go with 3/8” tenon. If you’re concerned with shoulder size, you could go down to 5/16”. If you are using a mortising machine, anyway. Most hand chisels are not made in 5/16”, so that’s not a good option if you’re chopping by hand. I know that the standard method is to have tenon about 1/3 of stock width, but I usually prefer them a little thicker.

The reality of the matter is, M&T joints are so strong, I think you’ll be okay no matter what method you choose, as long as you take your time and make a good, snug joint and glue well.

-- Pete

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runswithscissors

2557 posts in 1858 days


#4 posted 08-09-2017 05:05 AM

I can’t see that the shoulder width is of much significance. I use 5/16 tenons as I have a mortising machine with a 5/16” chisel, and thicker tenons are obviously stronger. Of course if you are doing them by hand, that’s a different matter.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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