South Bend 9A 9B 9C and 10K approximate metric conversion gear (14.5 PA, 18DP)

thingiverse

14 point five degrees pressure angle, diametral pitch of eighteen. Converts your existing eighty-tooth idler gear to an eighty-sixty-three compound gear, offering a very good approximation to the one twenty-seven-to-one hundred gear for cutting metric threads. The approximation error is point zero one two five percent or one thousand five hundreds over a foot. I have two versions. A whole gear with holes for ten thirty-two screws, and a rim gear whose inner diameter is two point seven five inches. In the photos, I show the rim gear, printed in nylon with carbon fiber reinforcements, along with a twenty-four-tooth stud gear. Print gears in solid, or maximize the number of wall strata so that all teeth and their bases are solid; for the rest e.g. fifty percent infill would be plenty. In the photo, I show the sixty-three-tooth rim gear on a machined pulley, as mounted on my lathe. I also show a twenty-four-tooth stud gear. See my other thing for various stud gears you can print: https://www.thingiverse.com/thing:2993592 Take a look at MrPete's videos, e.g. https://www.youtube.com/watch?v=V6Aq0d1070I These things can work in a pinch or for hobby work.