>>>> Seeing as the purpose of this looser joint is to allow for cross-grain expansion, is there worry of any hard finish that crosses that joint cracking later on if the wood does expand that much?
Yes, if there is any movement along the seam, the finish will be "cracked". That's just the way it is. In some cases the movement is not enough that is exceeds the elasticity of the finishing material. Oil based varnishes and poly varnish are more flexible than waterborne poly, lacquer and shellac. If those finishes are used. There will be a cracking of the finish over the seam. It's one of the reasons I try to talk folks out of using them.
Last edited by HowardAcheson; 11-16-2013 at 04:43 PM.