Mortise Pal Vs Jessem Doweling Jigs? More Strength?

[allan kuntz]

I just built a blanket box for my wife from 3/4 birch plywod and used the Jessem and it worked perfect. I would not use mortise on ply wood but you could use a spline. A lot of old furniture was made with either method. Chairs come to mind which have a lot of stress. I have refinished a lot of chairs and the dowels seem to hold up better than the mortise. It all depends on what you are making

[mreza Salav]

I would argue that the difference of strength of mortises created by mortise pal vs dowels is irrelevant in almost all applications. Do a joint with 4-5 dowels and try to break it. Almost always the wood breaks. What I'm trying to say is more strength is a factor that shouldn't come to play at all since both are strong enough.
I have domino and both versions of Jessem doweling jig and a jig similar to mortis pal to use with routers. Fastests is domiono, most accurate is Jessem doweling jig and I do use it sometimes over domino. I don't use the router jig anymore (almost never).
Note that there are applications that you cannot do a mortise (or at least without a lot of pain) but doing dowels is quite easy, (imagine the end of a 3/4"x1.5" stock to attach somewhere else).

[glenn bradley]

Looking at the bright side, now that Mortise Pal is sadly no more your number of choices is at least limited. Glad I have one and wish I hadn't sold my old one. Perfect accuracy every time. You make your own tenon stock so there is not quality or variation issues like with dowels and biscuits. If I was a production shop I would definitely look at the Domino but, it would have to earn its keep and with my output that isn't going to happen. The MP gives you the large long-grain to long-grain glue surface that table aprons and chair stretchers benefit from. On the other hand, Sam Maloof's tables use a pair of large dowels into end grain on the legs. There is a supplemental brace to add the required strength that assures a long life but, this is to add strength to an artistic form. The point is, use what works best for you and your designs. I favor the Mortise Pal or standard M&T. I also use the MP for doweling so for me, its win-win.

[richard poitras]

I think Dowelmax has a stress chart on their site in regards to dowels and mortises for strength...

I have a Dowelmax and like it. I made two sets of double bunk beds all with dowels for the joints and they have held up well for the last 10 years .

Richard

[Patrick Irish]

I was set on the MLCS horizontal mortising table wit a router. Looks cool but no stops for aligning. I'm leaning toward the Beadlock Pro actually now. I think it's a screw job price wise since you gotta add the 1/4" kit for another $50 so $200 total. Nice thing is tenons can be made with the router bit. I like how I can turn the drilled loose mortise into a standard mortise with the chisel guide if I want.

I go back and forth daily. I don't think the any of the kits allow for mortise on the face of a piece of wood. Not sure how to do that. Like the pic below. The Dowelmax allows it. Dont think the beadlock or jessem can.

diy7-large.jpg

[mreza Salav]

Yes, you can do the same with Jessam. Just remove the two vertical pieces.

[glenn bradley]

I made two sets of double bunk beds all with dowels for the joints and they have held up well for the last 10 years .

Richard

Now that's what I call a real world torture-test .

[Von Bickley]

I have the Jessem 8350 and had not had a chance to use it until yesterday. Built a couple of face frames and it worked just fine. Glad I bought it.

[Matthew Hills]

My (commercial) dining room chairs were built in 50's with dowels. Most of these joints have failed and have required repair. Heard this is common due to the high stress, and difficulty keeping dowels from shrinking out of round. I don't have any experience with full-mortised chairs to know if they'd hold up better, but that's probably the direction I'd go if I was building some myself.

I do think it is worthwhile having multiple joinery options, so choose whichever fits your upcoming projects.

Matt

[Mike Henderson]

My (commercial) dining room chairs were built in 50's with dowels. Most of these joints have failed and have required repair. Heard this is common due to the high stress, and difficulty keeping dowels from shrinking out of round. I don't have any experience with full-mortised chairs to know if they'd hold up better, but that's probably the direction I'd go if I was building some myself.

I do think it is worthwhile having multiple joinery options, so choose whichever fits your upcoming projects.

Matt

I've repaired quite a few chairs that came loose in the back of the seat - and which had two dowels in them to make the joint. Two dowels in that location is just not storng enough to stand up to the stress that joint takes when people rock back on a chair.

By the way, R. Bruce Hoadley (the wood guy) published an article in Fine Woodworking many years ago where he studied the failure mode of joints like that. His analysis was that the problem was not glue failure, or shrinkage of the dowels. The failure was actually wood failure. My experience is the same. When I take a doweled chair apart, there is wood stuck to the dowel, indicating that the glue did not fail. But the surface area is too small for the load and the wood that the glue is attached to fails. My experience is that the wood of the dowel does not fail - there's glue on the dowel and wood attached to the glue. It's the wood of the chair that fails.

Another indication of that failure mode is that if you try to put a regular sized dowel back into the hole, the hole will be too big, indicating that wood was actually removed from the hole.

It's all a matter of the amount of long grain to long grain glue surface area. And a mortise and tenon has more long grain to long grain surface area than dowels that will fit into the same space.

Mike