Threads without tears
!0/32 / 8/32 bolts ? Also known as 5/16 and 1/4 inch. The common misconception of the UNF 10/32 is that this denotes a size, BAe Filton being one of the worst offenders (I remember when I worked there).
OK here we go :
The Unified series (UNF) 10/ 32 . the 10 is the series Number. Begining at 0 Unified = 60 thau (0.060") each progression of the series is a progression of 13 thau (0.013") therefore 10 x 0.013" = 0.13" + the 60 thau we started with = 0.19"
The 32 is the number of threads per inch (TPI)
N.B the series becomes imperial at 1/4 inch and the progressions from there on are nominal inch fractions
From the above I can tell you that 8/32 Unified is 8 x 0.013 + 0.060
That is 0.164" and 32 threads per inch (the bolt now being smaller 8/32 is UNC)
It would not be possible to use a Unified 8/32 screw / bolt in a Unified 10 /32 nut (it would not pick up).
I believe that the problem with the BAC 1-11 incident (fresh air for the flight crew) may have been caused by a mismatch of old english nuts (BA series) and Unified bolts.