Ondrej Krejci <okrejci@...>
Those gears are an approximation for metric transposing. You can get close to 25 pitch, 25.something, but not exactly. One way, selecting 32 pitch will give 25.1914..., the other, selecting 20 pitch will give 25.4054... . You may get closer, depending on what other gears lead to the QC gear box and doing some math, fractions.
On Thursday, August 13, 2020, 12:00:37 PM EDT, drinkr55 via groups.io <drinkr@...> wrote:
I need to cut some 25 tpi threads on my south bend 9A qc lathe. I purchased a printed 37/47 transposing gear of eBay thinking it might work. I can’t seem to find any information on how and where to install the gear set on my lathe and how to cut the threads I need. Any pictures or advice would be great.