Bolt choice for rocker pivots

[swiftdrivr]

My Swift DB-1 uses Allen head, coarse thread, black-oxide coated bolts in the rockers at the center pivot point. I use AN everywhere else, but Allen heads are unavailable in AN, as far as I can tell. So, I am wondering what other people use, and where they get them, since I went and stressed my current bolts beyond my comfort level for re-use.

Thanks,

[Raleigh]

My Swift DB-1 uses Allen head, coarse thread, black-oxide coated bolts in the rockers at the center pivot point. I use AN everywhere else, but Allen heads are unavailable in AN, as far as I can tell. So, I am wondering what other people use, and where they get them, since I went and stressed my current bolts beyond my comfort level for re-use.

Thanks,

plenty of Internal wrenching / Allen head Fasteners used in Aviation. They are listed under NAS and MS part numbers but you may have to search for a coarse thread. Various Atlantic’s with Ground effect and high spring rates use AN-5 In the same location you describe. Your designers application of an coarse thread points to a relatively low load on these fasteners? What size bolts are they?
refer to page 95 of link below

https://www.skybolt.com/wp-content/u...-12-7-2017.pdf

[roadracer]

The original Swift DB-1 rocker bolts (front) are AN6-07A, rears are AN-6-11 and are fine thread. Yes, fine threads into an aluminum pivot shaft.

Someone has changed (improved?) the design. You may be better off to replace the aluminum rocker pivot shafts (back to fine threads) and return to the original AN bolts to take advantage of grip length and bolt strength. Those aluminum pivot shafts are a simple lathe project.

Finding authentic course thread bolts with the correct grip length will be a challenge. ARP may have something, but finding bolts from any other source, other than aircraft, will likely be from somewhere overseas and not worth the risk.
Good luck with this!

[swiftdrivr]

Okay, had a senior moment, and "mis-remembered" the thread pitch. They are 3/8-24 [fine thread] with a grip of 0.37 and total length minus head of 1.25"

My car has allen heads in all the rocker pivots, front and rear. I am not aware of an AN spec Allen heads, but will look under NAS and milspec and see what I can find. If not, it's not a problem for the rears at least, and that is where I did the damage, so I can get AN to work. Many thanks for the help.

[Rick Kirchner]

Examples:

https://www.aircraftspruce.com/catal...clickkey=39812

https://www.mcmaster.com/screws/sock...t-head-screws/

[924RACR]

Okay, had a senior moment, and "mis-remembered" the thread pitch. They are 3/8-24 [fine thread] with a grip of 0.37 and total length minus head of 1.25"

My car has allen heads in all the rocker pivots, front and rear. I am not aware of an AN spec Allen heads, but will look under NAS and milspec and see what I can find. If not, it's not a problem for the rears at least, and that is where I did the damage, so I can get AN to work. Many thanks for the help.

Those match mine, then (SE1-based chassis)... though it doesn't look like at least Aircraft Spruce has them up to 3/8"...

[swiftdrivr]

unknown price

nventory	0
Inventory Note	Need additional stock? Call (866) 889-8212 or email
Thread Size	3/8-24
Grip	0.375 in
Features	Internal Wrenching
Grip Tolerance	±0.010 in
Head Type	Key Locking
Total Length	1.062 in
Suggested Nuts for the Bolts	42FLW47FLWNAS1804NAS1805
Industry Standards/Certification	MS20006
Weight	.005 lb
Minimum Order Note	Minimum order is 1. Must order in increments of 1.
Estimated Ship Date	Ships within 10-14 days

[Rick Kirchner]

I have several of those style bolts. You will need a radiused washer under the head. They are serious bolts...

[924RACR]

Preferred also the specific allen-head type spring lock washer, which I was able to find at McMaster-Carr. Assuming this is the correct parts list?