Domino question regarding material thickness

erikfsn

Member
Joined
Apr 2, 2008
Messages
240
What is the thinnest stock recommended for the domino. I'm thinking of making a small piece with 3/8 inch cherry.
 
I think 1/2" is about the thinnest I think you'd want to use, and that's with the new 4mm dominos.

Fred
 
Like Fred said... It's recommended that the tenon be no more than a 1/3 of the thickness of your material.  4mm tenons would be approximately 1/3 of the thickness of 1/2" material. 

You may be able to get away using it 3/8" but I would use a scrap to test.  Maybe other members have tried it in thinner materials and can offer some advice.
 
I believe I mention the 1/3 ratio in my manual as a guideline, but that doesn't mean it cannot be exceeded as necessary, and this would be one of those times. Domino is not intended to work with material this thin, but by adding a spacer you can achieve the proper spacing. The only thing to watch out for is that you do not set the mortise height to be so close to the workpiece surface that it telegraphs through. Even though there is very little glue used for a Domino joint, if the mortise is very close to the surface, make sure to leave the workpiece surface un-surfaced until not only has the glue dried, but the added moisture from the wood had a chance to dry too.
 
I used the 5mm dominos on 3/8" oak and the resulting joint was very strong even before it was glued up.  This was before the 4mm dominos came out.  You may have some difficulties on softwoods but for hardwoods I didn't find it to be a problem.

Martin.
 
Like Martin, I would also not hesitate to use a domino that is one half the thickness of hard woods, one third for soft woods.  Dominos do not swell up like compressed biscuits do so  having a mortise that is half the thickness of the work piece still leaves one quarter of the thickness of the work piece above and below the mortise.  So long as the absolute wall thickness is at least 2mm I don't think it would cause you a problem.  I put 5mm dominos in the edge of 10mm hardwood book matched panels all the time.

Jerry
 
I have edge joined 6mm ply with 4mm dominos with no problems at all. But I only glued the edges of the ply and none in the mortise or on the Domi. Contrary to whats said about the Domies not swelling because they arnt compressed,  timber is timber and the cell/fibres will swell if introduced to moisture. So as a rule if you are going thin, dont use glue. And if end grain is part of your plan then forget it.  
 
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