Warp HP-L blade clamping bolt size?

[dholly 718]

Re: Warp Drive 3-blade prop w/ HP-L hub on 912ul.

While re-torqueing my prop and 1/4" blade clamping bolts I discovered galling on a few of the clamping bolts so I'm replacing all. Unfortunately, I can't find a definitive size for the clamping bolts in my docs, on the Warp site or here, and I don't have an old bolt handy.

Can anyone confirm my best guess of AN4-20A please? Tnx

[dholly 718]

Forgot to post my findings, apologies to anyone who wasted a trip.

The AN4-20A bolts are too long, IMHO. They will require at least (2), but more likely (3), AN960 thick washers (it is acceptable to use one washer under the bolt head and two under the nut). If you leave even one off you run the risk of bottoming the nut on the threads and galling the bolt, particularly if over-torquing the bolts, which is what I believe the prior owner did on mine. I stepped down to the next shorter 1/4" bolts, an AN4-17A, with a single washer under the nut. At first I wasn't sure I'd have enough thread out the back of the jam nut without changing to the thin washers, but all worked out when the bolts were torqued down.

HTH