Domino question

[tim walker]

I am building a beveled frame that is 3/4” x 2 3/4”. A panel will then be inserted. Since there is a dado cut, I am thinking one 5x30 domino centered perfectly. I am wrong in this thinking and should use two? The panel will help keep it from racking

[Paul F Franklin]

Unless it's a big frame, one domino will be plenty. I generally use 6mm dominoes in 3/4 stock and sometimes even 8mm. But 5mm should be fine, again, unless it's a big frame.

[Jim Dwight]

I agree size is not critical for this but at least a 6mm is preferable if there is room. I would not try to "perfectly center" it, however. I mess up sometimes getting the best side turned up when doing the glueup. Making the mortises a little off center is a way to mark which side goes up. It's also easier than trying to perfectly center the mortises. Cut all the mortises off the face with the fence roughly centered and the wood will line up.