Dowel Versus Mortise and Tenon Joints for Attaching Table Legs
Dowel joinery would save time on a large production run of tables. But will dowel joints be strong enough? October 1, 2010
I have a lot of maple tables with laminate tops to make (42 X 92), and in order to cut time, would like to use dowel joints. Is this a good idea? Are these joints trustworthy for this application?
(Furniture Making Forum)
From contributor J:
How many is a lot? I'd say it's not the greatest idea, but you could get by with it. I wouldn't do it without corner blocks glued and screwed in also. I assume you have an efficient, accurate way to do the doweling? If you don't, then forget it - it could be more trouble than you can imagine.
From the original questioner:
I have a CNC Gannomat index. Drills, glues, shoots dowel, and on to the next. Generally used for cabinet construction. These dowels are so tight in lumber, though, especially harder woods like maple, that it's better to gently tap them in to avoid splitting and swelling. It probably would work a lot better to use a 10mm bit and 9mm dowel. Not even sure if they make 9mm dowels.
Bottom line is that I know it will save tons of hours, but will it stand up to the test of time? Yes, I'll be using corner blocks glued, screwed, and bolted.
From contributor S:
There's no question that using the dowels would be inferior to M&T in my opinion. What is the expected life of the product is, and when you quoted the job, did you allow adequate time to M&T them?
If the tables are not expected to last more than 5-10 years, you would probably be okay (but definitely follow contributor J's advice and use corner blocks, too). However, if they are higher quality (higher priced), I would stick with M&T.
One other option to consider: loose tenons. They are considerably quicker to produce, especially for multiples. You could set up a couple of simple jigs with a router if you don't have a slot mortiser. You can then mill your tenon stock to width/thickness, and simply CC to length. Quick, easy, and strong.
From contributor D:
Furniture repair is a large part of my business, and over the years I've repaired hundreds of pieces with failed dowel joints, but I can't recall ever having had to repair a joint that was joined with mortise and tenon.
From contributor B:
The glue surface from a dowel into a hole is only along the long grain of the hole. This is such a small part of the hole. There is no bonding to the end grain. This is why dowels do not hold well. Also, one good kick to a table leg, or pushing a chair into the leg, can snap off a dowel. Do it right, use tenons.
From contributor L:
If you use corner blocks to pull your legs into the ends of your aprons, the dowels don't do much more than align the joint. Tenons would be stronger, but dowels should not be a problem. Make a test piece, especially if you are building many, and kick it to breaking to be sure.