Thread: BA taps

hello

I picked these up at a hamfest ..the guy had quite a lot of them at a giveaway price

I think they are mostly carbon steel so maybe only useable for softish metals-brass and aluminium ? He had #2 to 10 .... did I do well chaps ?

Mike

Originally Posted by morrisman

hello

I picked these up at a hamfest ..the guy had quite a lot of them at a giveaway price

I think they are mostly carbon steel so maybe only useable for softish metals-brass and aluminium ? He had #2 to 10 .... did I do well chaps ?

Mike

Mike
You did very well.
Very handy, thread taps in BA thread form.
Nothing wrong with carbon steel taps, treated carefully they will last for years, & yes they will tap steel very well. I have a set & have tapped heaps of all metals including steel, with no problems. The main thing to remember is to use the correct size tapping drill & cutting oil like "Tap Magic" or equivalent.Everyone has their favourite oil.
The Pratt & Whitney taps you got hold of are a collectable piece of history.
Enjoy your tapping!
regards
Bruce

That's an awesome pick up.

I concur about carbon steel. Nothing wrong with it. I think HSS became popular because of it's longevity in production work many years ago. Now they have TCT tools. For the home use and treated well, will be a good investment.

That's my uneducated opinion past onto me from my father who did his fitting & turning apprenticeship with AEG in germany just after the war....
He also showed me the grinder test to distinguish between carbon and HS steel.
Amazing the stuff you remember from your parents..

RIP Dad.

Simon

Righto .....Yes, I guess I was just fortunate for once .

I had an old Land Rover that used #3 BA tapped holes around the main windscreen frame to fix the outer frame ... what pain it was ... that car had many of those oddities come to think of it. I've been told or read somewhere , the even sizes are the norm in industry 2 4 6 etc ... I've seen many BA screws on older electronic gear as well .. valve radios etc. We can thank the Pomms for it.

Mike

Quite a good deal there. I believe carbon steel are harder than HSS but HSS is tougher and lasts longer,more wear resistant. Sounds a bit strange but I read it somewhere. I haven't confirmed it.

Originally Posted by morrisman

Righto .....Yes, I guess I was just fortunate for once .

I had an old Land Rover that used #3 BA tapped holes around the main windscreen frame to fix the outer frame ... what pain it was ... that car had many of those oddities come to think of it. I've been told or read somewhere , the even sizes are the norm in industry 2 4 6 etc ... I've seen many BA screws on older electronic gear as well .. valve radios etc. We can thank the Pomms for it.

Mike

Mike
Who else would come up with a thread form with an angle of 47 & a 1/2 degrees.
I have often wondered how that came about?
Bruce

BTW if anyone needs BA screws. Classic fasteners in Adelaide usually has a good range of them. MIKE

Classic Fasteners - Fasteners for your vehicle restoration project.

Originally Posted by Abratool

Mike
Who else would come up with a thread form with an angle of 47 & a 1/2 degrees.
I have often wondered how that came about?
Bruce

BA was a scientifically engineered threading system see here:

British Association screw threads - Wikipedia, the free encyclopedia

I suspect the 47.5deg form was for non interchangability between it and the other systems.

Is a thread that measure 3.05mm Dia and 5.3mm over 9 pitchs going to be anything other that 5BA?

Stuart

Stuart, that's pretty close to 43 TPI which suggests it is 5BA.

Originally Posted by Stustoys

Is a thread that measure 3.05mm Dia and 5.3mm over 9 pitchs going to be anything other that 5BA?

Stuart