SpudFiles

kenbo0422 wrote:. Heat it up and cool it down fast to harden it and you have a homemade tap.

this will not happen if the carbon content of the steel is too low heating and quenching a piece of mild steel wont cause it to harden significantly for that purpose you use a case hardening compound such as casinit (sp?) or something like that

this will not happen if the carbon content of the steel is too low heating and quenching a piece of mild steel wont cause it to harden significantly for that purpose you use a case hardening compound such as casinit (sp?) or something like that

OK, take a piece of milder CARBON steel and do it. If not, do as Heimo suggests.

have a look here to find the right steel for the job

http://www.onlinemetals.com/toolsteelguide.cfm

Alright, I guess i *could* attempt to make a tap, I will try and obtain the m6x0.75 die, i wouldn't of thought of that so thank you heimo!

@Gip. Yes i meant that as a last resort kind of thing, and thought you meant it as my main objective. Sorry about that.

I have not as of yet, managed to contact a factory or shrader valves, i will keep tryign tomorrow.

The taps are available on Ebay at £4.97 inc postage. (29/12/2012) ... set of 3 taps...I have just bought some.

Since the error is only + 0.007", put the second tap in a lathe.
Set up a simple rotary grinder using as fine a wheel as possible, set securely on the saddle.
Grind away the surplus SLOWLY and you will have a reasonable tap to suit the Shrader thread.

Use the 1st tap to briefly start the thread and, thereafter, only use the sacrificed 2nd tap to complete the thread.

Should you want to make a die, then, using a slug of any kind of tool steel - about 5/16 to 3/8" thick x 3/4 to 11/4" diameter , drill and tap the cutting hole ( a lathe is best) and plug the tapped hole with a softer steel thread.
Mark out and drill 3 equidistantly spaced swarf holes at 5/16" diameter.
Clear away the plug and harden the tool steel die.
An internal start taper in the tapped thread hole before threading will make this into a useful die.
As a toolmaker apprentice (3million years ago), I did this a number of times for my own set of dies and they all worked well -- and still do.

Any questions, I will be happy to help.

I will say that the angle formed by the holes/flutes on the die will have a significant impact on its cutting ability, as will their surface finish.

You may also consider 'drilling' the swarf holes with an center cutting endmill (after spot drilling to guide it), rather than finishing with a drill bit.