Geared Down Stepper Motors
- 27-1 is about what we need for 100 lb of drive force using a 1" pulley. . But only 425 oz in of torque. Only about 53 lb force at a 1/2" radius drive.
- Note you can get a Nema 34 for the same price - 
- For a similar price, we can get a nema 23 or 36 with no geardown.
- We need about 9x geardown compared to a regular motor based on acceptable force of belt (9x the belt width).But we need double sided drive for more force.
- Need 12 motors. It may be that 9x 3d printed planetary geardown is the way to go.
Compare to Nema 23
- 425 oz in - $36 - . More cost effective to use larger stepper.
- There are very strong Nema 34 motors that cost less for the drive force - $60 for 1200 oz in. 14 mm shaft with 5 mm keyway. 
- We can do a connecting shaft drive to drive 2 axes at once
- Still need $360 of motors here
- Only low cost way is 12*$8 = $100 if use 3D printed planetary geardowns with backlash correction.