Chriswal's Cycloidal Gear box improvements

I wanted to build on the great cycloidal gearbox by chriswal.

Changes and modified parts listed below, get the remaining unmodified parts from the original design by chriswal.

getriebedeckel -> getriebedeckel 625ZZ:

• Bearing changed to 625 for use with M5 output shaft,
• Created a second NEMA17 sized mounting flange to mount the gearbox to e.g. an extruder,
• Removed the original M3 nut mount features as I couldn't see how they would work.

getriebe -> getriebe-M3nut

• Modified to use an M3 nut as the threads for the retaining screw to motor shaft.

outputshaft -> outputshaft M5

• Modified to use an M5 screw as the output shaft.

wellenrad -> wellenrad remade

• Rebuilt the gear to get rid of the poorly printable tiny corners (see attached image).