As has been mentioned they seem to just be small taps.
I presume the the breakdown is screw size, threads per inch, thread type.
3-48NC
#3 screw, 48 threads per inch, national coarse threads.
I've never heard of #3 screws.
#4 is the smallest I have worded with.
I have a TRUECRAFT 31614 Cr-V 7/16" 3/8"drive socket.
It is stamped "JAPAN".
Does it have a warranty?
Is the warranty still being honored?
If so, how?
If anyone loves them, I am willing to sell it.
I have some tools that I'd like to learn about.
The are taps made by Pratt & Whitney Cutting Tools and Gauges.
They are new and still in the original packaging (cardboard and sealed in plastic).
They are labeled as follows:
3-48NC
23 108 041
6-32NC
10-24NC
30-108-043
4-40NC
24-108-041
I...