Change gears (imperial) for EMCO compact 5 lathe

thingiverse

3D-printed change gears for EMCO Compact 5 lathe EMCO compact 5 feed mechanism comes with 6 change gears (for common metric threads): 20, 25, 50 and 3x 60 teeth For uncommon threads or imperial threads additional change gears are needed: 26, 30, 34, 35, 36, 72 and 40 teeth While you can buy them from EMCO in Austria and they are beautifully cut from steel blanks, I wanted to print them on my 3d printer. The gears are 5.4mm thick and have a bore 14H7mm with a keyway (approx 4x1mm) I undersized them for the printing and reamed them to 14H7 using a hand reamer. As you can see in the foto, they fit perfectly. In the second and third picture you can see a 7/8"-14 UNF thread being cut, this uses only the 60 gear from EMCO and the other 3 gears are printed (72, 34, 35). Despite being a quite a large thread with heavy cuts, the printed gears work well. (hand-cranked, though). Cutting a 7/8-14 thread was the primary objective as that is the thread for my single stage reloading press and I am building a couple of custom dies. The scad file is fully parametric and can be changed as required. You need the parametric involute gears (see credits below) in the same directory. I printed at 0.4mm with 30% infill and 3 perimeter in PLA. Credits: openscad code written from scratch by me, stemer114 using the example code from parametric involute spur gears library (see below) Credits: Parametric Involute Bevel and Spur Gears by GregFrost It is licensed under the Creative Commons - GNU LGPL 2.1 license. (c) 2010 by GregFrost http://www.thingiverse.com/thing:3575 This module makes use of the polyhole library function by nophead (MCAD library) MCAD Library - Polyholes Copyright 2011 Nophead (of RepRap fame) It is licensed under the terms of Creative Commons Attribution 3.0 Unported. https://github.com/SolidCode/MCAD/blob/master/polyholes.scad