ok...broke 4 so far...no prob getting them in with tuffpack....frame fully clean and painted...screw holes tapped and the little metal 1/4" joiner pieces are in good shape(and straight)...but the glass keeps cracking at the frame seam(where the two halves join)....mic'd the channel and its fine....any ideas...i'm at wits end and now think if i cut the glass 1/16th or so smaller perhaps it wont crack....pissin me off cause it goes in great..then sits on the bench and within 15 mins, breako....please help