127T change gear for cutting metric threads on a Harrison L5 lathe

The 127T gear is necessary for cutting metric threads on the imperial Harrison L5 lathe. (12.7mm is precisely ½" so 127T gives an exact conversion). Other gears needed to cover almost the full range of metric thread pitches are 40T,50T, 60T and 63T. I remixed this from my previous Harrison gear code that uses customiser to allow you to dial up the number of teeth you want. I would not recommend running with plastic on plastic but I have run 3D printed gears against steel gears for a while now and they seem to work fine.

Update: See my remix of this (http://www.thingiverse.com/thing:1808219) if you already have a 100T gear and never want to use both 100T and 127T at the same time. The remix uses less plastic, is quicker to print and can be printed on a 150mm square bed piece by piece or all at once on a 200mm square bed. Which is easier to make? I'll post another update once I have made the 127T-100T remix. I think the full 127T gear would be more convenient if you want to switch between metric and imperial thread cutting.