Malcolm wrote:It looks as if those screws go through the tabs straight into the acetal block. I'm sure it would take a thread easily, but not so sure I would want to rely on it for consistent clamping, especially if you want to reconfigure cells any time in the future. Maybe use rivnuts/nutserts?
I agree, metal inserts pulled in from behind would be a good idea here. If they can't be used, I recommend that the plastic be threaded for the largest bolt possible using UNC (coarse) threads, not UNF (fine), and should be as thick as possible (1/2" would be great).
Even then, you can't tighten the bolt too much. And, the plastic and bolt have very different expansion/contraction rates when heated/cooled and this will encourage loosening of the bolt over time. I recommend using a threadlocker compound. But, some aren't rated for use with such a slippery plastic so check the specs.