12-32 bolts

[belmont]

I found a bag of 12-32 bolts in my stash and have no idea where they were used. They are 15/16" long, full thread and have a 3/8" hex head. Cad plated and I have 63 of these little beauties to find a use for.

Anyone have some info on why Harley dealer from the late 30's to mid 80's would have them?

Thanks for any info on this oddity. belmont

[Rubone]

7/32 -32 is the thread size of the tank top screws for everything from Js to 45s.

[T. Cotten]

7/32 -32 is the thread size of the tank top screws for everything from Js to 45s.

Don't forget 3532-18S, which is "oversize".

....Cotten

[Steve Slocombe]

12 x 32 is very close to 7/32 x 32 so they are probably 3532-18 tank top screws. With 6 used on the JD and 5 on the VL you will get through 63 of them quite quickly.

[T. Cotten]

We may never know, Folks,...

But I wonder if the 3532-18S, which is "oversize", was accompanied by an over-sized tap?

How else would you use it?

....Cotten

[belmont]

Cotten, do you think maybe the oversize is 1/4-32 thread?

I have a 1/4-32 tap that I use to clean the threads for the 70's front brake light switches.

Thanks for the help on my little mystery. I never thought of 7/32 - 32 as being the same as 12-32. Been out of the machine shop for too long I guess.

Karel

[Steve Slocombe]

Yes the original oversize tank top screw is 1/4-32 although not all the repros may be identical, as 1/4-28 is a standard thread. I think the original 3532-18 were 12-32 as described, and I used to be able to buy old stock taps this size, but now use 7/32-32 which is within a few thou.

[Tommo]

NOS oversize tank bolts 1/4 x 32 DSCF4300.JPG

[belmont]

Thanks for all the help on this.

belmont