1/4-20x 1.65in Bolt for FAB to RSA5?

dmat · #1 06-01-2018, 06:21 AM

Hi all,

I have been trying to find a 1/4-20 x1.65inch grade 3 bolt as I needed to make a 1 inch spacer between the FAB and the servo and Mcmaster-Carr/Fastenal doesn't have it. Does anyone know where I could get this size?

I found a 3 incher which I could cut down but it doesn't have a drilled head for safety wire.

Thanks,
D

dmat · #2 06-01-2018, 08:24 AM

Would it be acceptable to use a bolt with lock washers in this area?

az_gila · #3 06-01-2018, 08:56 AM

This might do it. Under the old part number AN74A-16

https://www.bandbaircraftsupplies.co...mart&Itemid=73

dmat · #4 06-01-2018, 09:34 AM

Thanks AZ. I will try them.

cajunwings · #5 06-01-2018, 10:12 AM

You could drill the head yourself if you can?t find what you need.

Don Broussard
RV9 Rebuild in Progress
57 Pacer

dmat · #6 06-01-2018, 10:15 AM

I was thinking about doing the drilling but wasn't sure if grade 5 hardness will allow for it. Plus I would have to buy a jig (I think).

D

lr172 · #7 06-01-2018, 12:43 PM

I would make my own. I had these exact bolts with lock washers loosen up on my 6, so would recommend safety wire here. I made my own prop bolts and was able to drill the heads of grade 8 bolts, that are much harder than a grade 5. I think a grade 3 would also work in this application as there is not much load, just a lot of vibration.

Use a cobalt 1/16" bit on a drill press and you should be able to get it done. Go slow and use oil. No jig necessary, just a spacer under the threaded part of the bolt to keep the head perpendicular to the drill bit. The bolt's flat will keep everything stable once you have the right sized spacer. Buy an extra bolt in case you break off a bit in the head, but that shouldn't happen with a grade 3 or 5.

Larry

rocketman1988 · #8 06-01-2018, 01:23 PM

I think that an74 bolt is 1/4-28 not 1/4-20...

I used some Nordlock washers on my throttle body bolts...still thinking about drilling the heads though....

az_gila · #9 06-01-2018, 01:41 PM

Quote:

Originally Posted by rocketman1988

I think that an74 bolt is 1/4-28 not 1/4-20...

I used some Nordlock washers on my throttle body bolts...still thinking about drilling the heads though....

AN74A is coarse thread... check the specs and the description in the link I posted...

rocketman1988 · #10 06-01-2018, 03:28 PM

You know I was looking for those bolts and couldn?t find them. 1/4-20 they are...

Thanks!