just find an industrial hardware place like
McFadden-Dale Hardware or
McMaster-Carr and buy them.
i got black, grade 8 socket caps for every bolt on my motor, and button heads for my sprocket, for under 5 bucks at mcfadden-dale near my house.
you're not building a rocket ship. grade 8 will outlast your motor.
also, this is my opinion only, but throw that loktite away, and get some anti-seize. tighten everything properly, and relax.
i haven't lost a bolt, stripped a bolt, snapped a bolt, or had to tighten a bolt since i put mine together. and yes, i check them now and then.
now, if any of you really wanna get all technical about it, so you can be the "ultimate hardware know-it-all," go here:
Fastener Stress Analysis Reference Library, On-Line.
then come back here and tell us what's the best. should take you a few years to figure it all out...