Originally Posted by
ZAGNUT
only reason to stick with one of the standard prop screw patterns is borrowing props from other modellers. for your engine size that would mean the 29mm xM5 pattern but that sounds like it won't work with the bore in your hub. larger pattern with M6 screws will be far more robust and less likely to shear screws...but then that might be a good feature to have in a ground strike, easier to replace a prop and screws that to straighten the crank.
The socket required a 25mm counterbore. I might be able to use the 34 m pattern with 5 mm screws. Not sure yet, have yet to draw it out. Otherwise, it will be the 35 mm pattern and 6mm screws I guess.
for what you're doing a piece of 10mm G10 would work for the insulator. another material is that phenolic panel stuff often used as dividers in public restrooms....i imagine that might be easy to find at a recycling/junk yard.
I've seen that stuff at the recyclers. Sometimes used as electrical power boards too.