Henry's Bizarro threads!

I grew up in an old time hardware store, and 40 years ago we stocked #12-24 fasteners as a regular item. I don't know when it occurred, but the #12-24 started disappearing from our suppliers. I think the machine screw numbering system was aligned with the wood screws and sheet metal screw numbering system. The head sizes, especially the flat head screws, are sized the same as the wood screws. We never thought of them as a gage size, but referred to them by number (#), such as #12-24, #10-24, & etc. The gage size did not relate, as Terry says, they are opposite, with the numbering in opposite directions, size wise. For example 10 ga steel is .1046" thick while a #10 screw is .190". No correlation.
 
My local bolt supplier stocks 12-24, and the local hardware store also has them. I have them in my stock also. Nothing strange about 12-24.
 
If you ever had a classic British motorcycle you did the
British Standard Whitworth Thread dance.
 
Just to be sure no one makes any mistakes about this subject, I'm going to list some of the lesser known thread sizes. Both fractional and the numerical systems.
0 X 80, 1 X 72 & 80, 2 X 56 and I will skip over some, 3 X 48, 4 X 36 & 40 , 5 X 40, Here's one you weren't expecting 7 X 32 and 9 X 32, 10 X 32, 24, 28, 30, Then the 12s in24, 28 & 32, And the ever popular 14 X 20 & 24 (major Dia .242) And the small fract. sizes by 1/64 th
to 15/64 X24 . 15/64 is .235 , #14 is .242 and of course 1/4 is .250. So you see, the magical world of threads is a deep bottomless pit. I got go eat now, but you see what I mean. Terry
 
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