Originally Posted by
spclark
Metric button-head cap screw, M3 - 0.5 10.9 grade I'd think.
Here's mine with my cobbled-up FW 'holder clamped in my bench vise:
Several sets of holes for different size BIGS.
Funny too those Nylock nuts on mine were peened... not that that had much effect on keeping nuts tight, maybe something from prior 'slippage' at the LBS?
That M5 bolt really should be a shoulder bolt with the threads starting beyond the chain width. Those threads are just asking to be the failure starter. (The bolts are cheap so probably cost effective it replace them vs probably much more expensive perhaps custom made bolts. But where you end up and how could swing the $$ pendulum
Just thought had the thought - a clevis pin. I bet there is a metric one of the appropriate length. No threads at all. Secured with a cotter pin. (Takes me back to my sailing days. But get an industrial one, not a ss marine one. Good tool steel is a lot stronger and harder. Grainger or MacMaster-Carr?