Help with old Tap / Die sets

[muskrat man]

I was down with cancer all year and during my treatments my dad was hitting the yard sales for me. He picked up a pile of tap and die sets from an estate where an apparent machinist had passed away. Anyway all that was left was the tap/die sets so he got the pile for $50. There is a large set of standard taps that are marked M.T. Inc. Any idea who this manufacturer is? There are also a large number of metric dies marked WHIT Made in England. Again, identification would be appreciated. There are a number of other manufacturers as well that I will ask about later.

There are a couple sets of smaller tap/dies that are marked 1 BA, 2BA, 3 BA and so on, are these metric or some proprietary thread? May be a dumb question but I only ask because I have no clue. All I have ever used or had the need to use were standard. I may someday find use for these but I cannot apply them if I don't know what they are.

Thanks in advanced

 

[ibedayank]

whitworth thread ie whit is not metric

nor is BCS british cycle standard

BA (British Association) Thread

 

[d.mcfarland]

More importantly, glad to here you are doing better (it sounds like at least).

 

[paulsomlo]

1BA, 2BA, etc., refers to the thread class, or tolerance (fit). Here's some info: http://www.engineersedge.com/thread_strength/thread_classes.htm

Yes, WHIT would probably denote Whitworth, which is a British standard for screw threads, a 55 degree V thread (vs. our 60 deg. American standard). Here's some more info: https://en.wikipedia.org/wiki/British_Standard_Whitworth

 

[Dave455]

O.K. Mate! Some good info here, but also some misinformation!

Allow a Brit to help!

'Whit' is short for Whitworth. Whitworth threads are basically the British equivalent of Anerican 'National Coarse'. The 'Made in England' kinda confirms this!

The die will probably say something such as '1/4 Whit' meaning it will cut a 1/4 inch Whitworth thread!

You might also find say 1/4 BSF. This stands for British Standard Fine and is the British equivalent of American National Fine (which you would call SAE).

Unlike the American threads, which have a 'numbered series' for the smaller sizes, British threads do not. Instead we use BA or 'British Association'. Unlike the American threads, the bigger the number, the smaller the thread, so these go down to some really small sizes for instrument and clockmaking!

You will find Whitworth or BSF threads on any British made vehicle up till 1958, or aircraft till slightly earlier. Many machine tools and accessories used the threadform much later, and you will still find stuff that uses it.

BA threads were used much later as the U.K. never adopted the Unified numbered series. You will find them on instruments, electrical equipment, small tools, guns, and ell over.

Popular BA sizes are 0,2,4,6 and 8. Odd sizes come up sometimes too, 5 BA is used on SU petrol pumps, 7 BA on some carbs.

 

[muskrat man]

thanks for the info. Now I need to decide if I will ever use them, I may never have application for them

 

[2oolhound]

I may be interested in them depending on size and condition. I mainly need the bigger ones and need some dies. I'll pm you.