12-27-2013, 10:03 PM
Breakthrough! I was researching using various change gears to convert to metric, hoping I could reverse the process with gears I have to cut standard threads. I went down to look at the QCGB charts again and it occurred to me that the lower chart actually referred to standard threads.
The headings that mention the 40- and 45-tooth gears have the same wording as the ones in the top chart (that covers metric threads) for the first and last gears. After I changed the 80-tooth to 40 and the 127 to 45, every test I ran produced the thread shown on the chart.
It can cut 32 standard threads, from 3 to 44 tpi, some with half-values, like 9 1/2 tpi.
The headings that mention the 40- and 45-tooth gears have the same wording as the ones in the top chart (that covers metric threads) for the first and last gears. After I changed the 80-tooth to 40 and the 127 to 45, every test I ran produced the thread shown on the chart.
It can cut 32 standard threads, from 3 to 44 tpi, some with half-values, like 9 1/2 tpi.
Mike
If you can't get one, make one.
Hawkeye, proud to be a member of MetalworkingFun Forum since Jan 2013.
If you can't get one, make one.
Hawkeye, proud to be a member of MetalworkingFun Forum since Jan 2013.