Stacey

Outside threading I have found is 0.305" OD, 0.302" root diameter x 32 TPI which I believe translates to a 12-32 bolt.

Where can I get a short bolt of this threading or find a die to thread it with?

Or, does anyone have a junk tube with the all-thread valve stems that wants to part with it?

OLDYELLR

What, exactly, do you want to do? Why not just use an actual Schrader valve?

I_bRAD

Sounds more like a 5/16 bolt. #12 is way smaller than that. Standard 5/16 thread is 18 and 24 though so it is an oddball size.

What are you trying to make?

Stacey

I have a Smiley face schrader valve cap that matches the one in the photo below.

I want to attach its mate to the back of my seat or maybe a rack. A standard butyl schrader stem wouldnt work. I'd want to use a bolt to attach the cap with.

I_bRAD

If you can't find the bolt you need and you don't care to use it on a valve again you could just use a standard 5/16 setscrew(no head) and some glue (I'm assuming it's fairly soft plastic and you could just force it in) and then fasten it with a nut.

Stacey

It is plastic, but there's an metal insert that seems to be cast in place.

I was thinking of grinding down the head of a bolt to fit inside, then just JB Weld it in place so there's a stud sticking out and putting a nut on that.

Bill Kapaun

It's a 5/16" Extra fine, aka 5/16-32.
Now where to....

OLDYELLR

Have a look in an auto parts store where they have tire repair stuff, or a farm supply, like TSC. Many lawn tractor tires use tubes with long stems you could cut down. Another source would be a shop that services truck tires. They probably have something in the scrap barrel you can use.

Al1943

Years ago I had a truck tube that I pulled behind my boat. It had a long threaded valve stem. As suggested above, just find an old truck tube at the local truckstop, you'll need a tube for a big truck.

Al

Stacey

Thanks, I'll look in that direction.

Stacey

Problem solved, easy solution!

I cut the schrader stem from an old inner tube and took the valve out. Fiddling around with various bolts I found that a standard bottle cage screw (5mm x .8 pitch) will screw in a couple 3 or 4 turns. I got out my handy tap & die set and rethreaded the inside thread to 5 x.8 and rechecked the bolt. It screwed all the way in.

So, I put a drop of blue locktite on the outside threads of the schrader stem and screwed the smiley face cap on the stem, chucked the cap in the vice with some soft jaws and cut the valve stem off flush with the cap using my hacksaw. Filed the cut face smooth and rechecked the bolt for threading.

Viola! The smilie cap is now ready to affix to a bike with a standard 5mm bolt.

Al1943

You da man!

Stacey

No, I da woman!

Al1943

Wow! sorry about that. I've known at least one "Stacey" who was a man.
Anyway, my compliment was meant to be generic, and I'm equally impressed with your resourcefulness. The way you engineered this job sounds like something I might have done.

Al

Stacey

No worries, my father was Stacy... no 'e'.

Here's a pic of the finished project.

I used a seatpost reflector clamp (modified a bit) to mount the smilie orb to the bike.

I would like to take a moment to thank VegaVixen for the project concept.