Schrader Valve caps

[Ian Williams]

Can anybody confirm what thread is used on the original Schrader valve caps, it seems to be a bit of an odd ball, either 24 or 25 tpi I think and .480" diameter???

[Dave Wheatley]

A quick google throws this up

http://www.practicalmachinist.com/vb/gen...ze-219531/

But doesn't tie in with .480" x24/25

[Alan]

Valve stem thread is either 5V2 or 8V1

[Stuart Giles]

Thread dimensions here: http://www.gewinde-normen.de/en/valve-thread.html

[williamsderbys]

From memory (started work there in 1956..) It's .302-32
Tracy Tools probably got taps & Dies.
I have one of Schraders repair tools which might work for you.
e-mail if you would like to loan.
John W

[Ian Williams]

Thanks for the responses, according to Stuarts link it would appear that I am looking for Vg 12. Tracy tools only list taps for the modern threads i.e .302-32, I am looking to cut threads for the original Vintage caps.

[David Cochrane]

Having measured some original ones I have, they seem to be 15/32" x 26tpi. I haven't managed to find any taps or dies yet.

[Ritchie Wilson]

Valve tools have a die and tap to cleanup the threads on the valve. If an old enough one was found it would have the appropriate die.
Some people collect this sort of stuff and could have the right one.

[Robert Leigh]

Having measured some original ones I have, they seem to be 15/32" x 26tpi. I haven't managed to find any taps or dies yet.

Your details confirm what I suspected: it looks like a CEI thread (Cycle Engineers Institute). Even big sidecar lugs on old motorcycles are 26 tpi.

[Ken Morton]

I can confirm that the valve tube from the inflatable tube is .307 inch OD & 32 tpi. The old type fluted cover over the complete valve & tube is 12 mm by 1 mm pitch.