Daft Question: Why are SCHRADER VALVE TAPS So Expensive?

[SteveW]

Guys,

Another daft non-steam related project this end: I bought a new combined Schrader/Prestel valve adaptor necessary to pump my bike tyres up. Yes I already have a little hand pump but with 29" wheels and fat tyres I wanted to use my old and many times repaired foot pump. Halfords to the rescue with a dual purpose attachment complete with multiple fittings to a/any pump, none of which fitted. Its make stuff time again.

So resolved to make a new bit and a bit of lathe threading I start looking for taps to fit the supplied adaptors and just dropped across a set of Schrader taps: source of Schrader Taps What the ... !!!

For the curious I need the bit that screws in the end of the foot pump cylinder, a 'T' off for the gauge and will accept one of the supplied adaptors to the quite complex hose fitting. The current bit is plastic with a crimp secured hose and no I don't want to cut up the new hose and cobble it all together. The good news being I don't need any Schrader valve taps.

[cplmickey]

You did well to find some taps. I remember looking a few years ago and drawing a blank - don't know why Tracy Tools didn't come up trumps as they're one of my regular go-to suppliers.
Schrader valves make excellent non-return valves for loco oil lines and seem to prevent blow back through the tank which emulsifies the oil.
Ian

[SteveW]

and then I found this detail on the Schrader site

You never know when you'll need this stuff.

Thread detail reported as:

Outer thread 0.307 x 32tpi
Inner thread 0.210 x 36tpi

That document above includes a Schrader valve stem profile and that one should not re-use a valve core once removed. Who knew?

[ettingtonliam]

Not as weird as the European Standard valve which has a 5.23 x 0.705mm thread!

I wonder what strange thread profile they use? They don't seem to say.

[Jim]

i got mine at the local bike shop. It's a small multi tool that recuts the outer and inner threads along with a keyed tool to remove the valve. Not flash but handy and cheap.

Jim

[firebird]

Hi
A while back I did some experiments using schrader valves in a whistle valve with some success.

I stripped the core out of a tubeless tyre valve



Then in the mill I machined away exactly half to have a look inside.



I ended up making a pair of taps to cut the thread



This was my first attempt at tap making and they worked reasonably well in brass

Cheers

Rich

[mbrown]

Neat work Rich. Did the insides of the Schrader valve cope OK with the steam temperature in a whistle valve?

Malcolm

[firebird]

Hi Malcolm

Yes it did.

I wrote an article which was published in Engineering In Miniature detailing my trials.

I used a schrader valve with a green seal which has a higher temperature range than the standard tyre valve

Cheers

Rich

[Jim]

I've also used them in the steam oil delivery lines where they worked perfectly.

Jim