1970 1.7 liter is at machine shop out for balancing: impeller thru flywheel. Forgot to give machinist the three "multi-tooth socket head screws" that attach it to the fan hub, but now can't find them. So need to take a trip to Ace hardware.
What is bolt size and thread pattern ?
A little spring washer goes underneath too, right ?
Seems I used an allen bolt replacement for my last engine a couple years ago.

Standard M8, I think thread pitch is 1.25.

--DD

M8 x 30 mm is what is listed in the Porsche PET diagram. I believe the standard pitch
for M8 is 1.25, as Dave mentioned.

Be careful that the correct length is used. If too long the end of the bolt will carve out the flywheel seal. If you have an early fan with the raised cone in the center with a black insert the bolts are a different length than the later fans with a flat center, A CV bolt can be cut to length. Originals were a shallow head triple square that stripped easily. And a Schroor washer ( double sided serrated lock washer ) is the correct washer to use. Same as the CV washers.