I just got a piece of SRBP to try. It's incredible that it's made out of resin and paper, it looks really tough and quite heavy. I only got a 400x300 piece, in 15mm, as it's quite expensive, I think you use larger sheets?. I am guessing that Tufnol is a brand name, but the same thing?

I just wanted to ask roughly how thin does it get before you discard it, with regards to having enough thread left in the holes with sufficient strength to clamp the piece, 8mm or so? If you use M5 bolts, I suppose you need a good 5mm of thread? Secondly, I assume that you don't skim it every time you cut a new piece, provided you have enough of a flat, clean area left for the next piece to sit flat, is that right? Also, what's your favourite tool for skimming the SRBP? Does it machine similarly to Delrin? (the only plastic I have machined).
Keep on posting about your progress, the more the merrier:)

Edward