Square thread

[pommyphil]

Hi Is it possible to buy a tap and die for 1/2" square thread, (or even acme or buttress) or must they be cut on a lathe ?

[joe greiner]

An excellent question.

I doubt that square-thread taps would be feasible because of difficulty in clearing the swarf. Even so, Machinery's Handbook provides some tables of tap tapers for Acme and square taps; seems to be silent on dies. I suspect most of these tools would be shop-made for shop use.

Global (not WWF) Google [acme tap die] got many thousand hits; augmenting the keywords with [australia] reduced the hit list by about 2/3, and included an outfit in California, who apparently export all over.

Joe

[BobL]

Hi Is it possible to buy a tap and die for 1/2" square thread, (or even acme or buttress) or must they be cut on a lathe ?

http://www.victornet.com/cgi-bin/vic...43%2C507%2C596

1/2" Acme Tap, $48

No Dies though.
But
If you have a tap you can always make a die!
Come to think of it - at that price I might have ago at making the tap as well!

[watson]

You're a gem BobL,
I once ordered 3M of acme thread...expensive.
I thought whilst I was at it, I'd order some nuts to fit.....gasp...$13:80 per nut
Thanks heaps for the link

[BobL]

You're a gem BobL,

Gee - I haven't been called that since primary school!

I once ordered 3M of acme thread...expensive.
I thought whilst I was at it, I'd order some nuts to fit.....gasp...$13:80 per nut
Thanks heaps for the link

crickey 3M - what for?

[watson]

I live a bit off the beaten track, so if I need 4 threaded inserts for a project, I buy 20. Hence, the 3 Metres........when I fall off the perch..it'll be an interesting clearance sale


great link though.

[BobL]

I live a bit off the beaten track, so if I need 4 threaded inserts for a project, I buy 20. Hence, the 3 Metres........when I fall off the perch..it'll be an interesting clearance sale


great link though.

I didn't think anywhere in Vic was orf the beaten track?

[watson]

Not really, but transport companies treat it that way.

[Ashore]

Well bugger me when I first saw this thread I thought there couldn't possibly any acme taps , I have turned a few for foriegn order vices , but taps , never I started to have a quick look then I come back and bob and joe have links for them , this forum never ceases to amaze me

[.RC.]

I have read that some people either buy or turn the rod they need but make it a bit longer than necessary and use the excess to make a tap..

[pommyphil]

Well done gentlemen,amazing. I'll be ordering a 3/8 & 1/2 if anyone wants to share the freight ? Thanks again.

[Kody]

Check this site out for some hard to find taps and dies.
http://www.tapcousa.com/?gclid=COHN2...FQwxiQodNEbe1w
The smallest external Acme thread I ever cut was 0.250" in diameter and 2 inches long. I then had to make a special shaped nut and screwcut it to fit the shaft with no slop whatsoever. It was a great job to do and was part of my steam loco Simplex. It's not hard to do if you have a lathe. The hardest part is accurately shaping the cutting tools. I silver soldered the internal toolbit to the end of a small Allen key to do the job.
Kody

[lightwood]

Hi Is it possible to buy a tap and die for 1/2" square thread, (or even acme or buttress) or must they be cut on a lathe ?

PP,
It certainly is possible to make a workable square thread tap for brass, especially cast stuff like Spiers levercaps.
I recently bought the tools from the estate of 2 generations of artisans, including a lovely little Drummond Bros lathe and all the tooling made for it since 1911 (receipt was included) The Grandfather was a Jeweller, pipe maker and Ivory and tortoise shell worker, the Father was an engineer.
http://www.petermcbride.com/slomell_tools/

In my collection I have more than a few Spiers planes, including ones made by Spiers but marked, Buck, Mathieson, and others. All of them have 14 tpi square threads, and the diameter of the threaded part of the screw on about 4 of them interestingly is 12mm. So I made a tap on the Drummond lathe using 12mm silver steel rod and a cutter I ground myself. Then used the same setup to make brass screws. This took me a whole weekend, making one for a trial, then another, and breaking a cutter etc...good thing I wasn't paying for the time!! A competent machinist might do it in minutes rather than my hours. The 14tpi gives a nice lock down feel, the 10 or 12 tpi is a little quick I think. For example, ALL my Norris ( early and late), Mathieson and Spiers are 14tpi, Holland is 16tpi, Preston is 16tpi, Slater is the odd one at 11tpi.
Regards,
Peter