Hi Colin, I've a few calipers apart ready for recoating but haven't decided what to coat them with yet.
The bolts are M10 x 70mm 1.5 pitch with 34mm of thread, however the threads only engage 11 or 12mm. I think they are grade 8.8
The mounting bolts are M12 x 36 x 1,5 pitch with 22mm of thread. They are grade 8.8.
For reference the complete calipers are a few grams over 2kgs including spacers, pistons, seals and connecting bolts.