I found 2 sets of blade type screw gauges, that I have been wanting for ever, a NNB metric with some insanely fine pitches and a an old L. S. Starrett imperial one. The smallest size I can read is marked 24 - .072 which is useful for me, and there are 4 sizes smaller, stamped quite poorly over the whole set, but I think the blades must be very hard. the 1st number is obviously TPI ...
Other numbers are e.g. 12 - .114 , where .114 is obviously twice .072, but other than that I can see no relationship, and 14 123 and 11 - 157 etc.
What is the meaning and/or practical application of the second set of numbers? Tried some numbers to see if it was thread depth or something ...
Another one of my interminable Questions ...
Chow
Ant
Other numbers are e.g. 12 - .114 , where .114 is obviously twice .072, but other than that I can see no relationship, and 14 123 and 11 - 157 etc.
What is the meaning and/or practical application of the second set of numbers? Tried some numbers to see if it was thread depth or something ...
Another one of my interminable Questions ...
Chow
Ant
