Domino Thickness

[JOHN316]

I understand that the domino thickness should be about 1/3 the thickness of the material being joined, but what about the length of the domino. If for example two boards 5" wide are joined together with dominos, what should the length of the dominos be ?

I am considering the Domino 500 vrs the Domino XL 700.
95 % of the work that I do could be handled by the 500, although I would like to attempt joining boards with dominos longer than the 10x24x50mm dominos.

My question is: Has anyone tried cutting a domino slot with the 500 then hand drilling (with a 10mm drill) a deeper slot and custom cutting the beech domino stock to what ever length of domino is needed ?

Thanks

 

[Birdhunter]

I'm an engineer., abet retired, and I look at the stresses likely put on the joint. High stresses point to longer tenons while following the 1/3 guideline.

My first reaction to your idea of drilling out the mortise for greater depth is that you are defeating the labor saving aspect of the Domino system. Unless you are extremely careful, you could get a sloppy fit for the tenon and lose strength instead of increasing it.

I'm building 8 benches out of Ipe. The tops are 3 1X6 boards 6' long. I'm using 7 8X40 Sipo tenons between each board. That combination should accommodate and stresses the benches should incur.

I've got both Domino machines and I will be using only the XL 700 on this project because I want the XL's depth and its power as Ipe is extremely hard.

 

[Jesse Cloud]

I agree with Birdhunter.  But the 1/3 guideline is just that, a guideline, not written in stone or particularly scientific.  The idea is basically thicker is better, but don't go so thick that you wind up with thin fragile walls surrounding a big fat tenon.  As Birdhunter points out, the true issue is how much stress will be placed on the joint.  If you are building a big heavy door or perhaps a bench, longer is a good idea.  If you are making a cutting board, it doesn't matter much.

If you are making a chair, you probably won't have the option of a long tenon, so you may chose multiple shorter tenons if your stock is thick enough.

The rules for Dominoes are no different than those for other tenons.

Perhaps if you told us what you want to build we could offer better advice....