Possible to break a domino join?

[NLJBHDWood]

First time poster. Ill keep it simple. I have constructed a large blackwood table for the school which will be utilised as a prayer table. Joining the legs to the frame was done by using two 100mm dominos. Now, from the leg to the outer edge of the frame, it was supposed to be offset by 10mm (frame 10mm offset from the edge sitting flush at the leg). For each 4 legs there are more or less 10mm, except one in which is only like 2 or 3mm. Now i was not there to glue to the frame together and was done by the somebody else so i was not aware of this to recently. Is there anyway to break this join so i can make off 10mm like planned - its really bugging me as im a nit picky person and want everything right. Thanks guys.

[bsrlee]

Trying to break the joint with almost certainly destroy the leg or the rail, or both. What will happen is that the outer layers of the wood will stay glued to the tennon and split away from the main piece of wood - at least that is what seems to happen in most of the 'test to destruction' tests that have been published over the years comparing M&T, Domino & biscuit/plate joinery. Sometimes both parts will split and loose bits, and the loose tennon can also break up leaving bits to be dug out of the mortise.

If you can live with the lower frame being a few millimetres smaller all round, then carefully saw the legs away from the rails, clean up the cut surfaces (plane, sand) and then re-cut the pockets for the loose tennons. Don't try to get the old tennon stock out of the parts, just cut straight through them when cutting the 'new' mortises.

[NLJBHDWood]

Alright, thanks. Ill have a talk to my teacher and see what happens.

[Evanism]

Agree with bsrlee, it will break horribly if you force it. It will need a lot of force too.

Just cut it with a Japanese thin kerf saw and a jig to keep it dead straight.

I've done this with table legs and chairs I've repaired for others.

With the dominos, if they are horrible once apart, just rebore them and glue in a new domino, once dry, trim them flat and you'll have new wood to re-re-do them properly. I've done this with dowels a million times. Same principle.