Min Thickness for Countersunk Bolts

[JesseK]

In attempting to improve last years drive train, I've run into a slight snag with multiple possible solutions. One is to use countersunk bolts in 4 locations to alleviate the issue. It's the most elegant solution so far, yet brings up a question.

The two pieces of metal to be attached are 1x1x1/16" box tubing and 1x2x1/8" box tubing. The countersink will happen in the 1x2x1/8" box tubing. Is this too thin? Is there a table of bolt diameters and/or minimum thicknesses for angles of countersunk bolts? There will be some sheer stresses on the bolts/boxes as well. Google hasn't been terribly helpful.

CAD to come on the overall drive train, soon. Thanks!