I'm throwing out some calculations to see if we are on target or have missed something.

We have a 10in arm that we are designing to lift 60lbs. The arm is driven by a 2in sprocket. The 2in sprocket is driven by a 1in sprocket (chain linking the two sprockets). The 1in sprocket is attached to the 3/8in output shaft of the motor.

What torque do we need out of the motor?

Using simple MA calculations and ignoring efficiency we have arrived at a value of approx. 160 in lbs.

Below is our calculation process

output lever has MA of 1:10 (radius of sprocket at 1" to length of arm at 10")

pulley system has MA of 2:1 (diameter of input sprocket at 1", diameter at output sprocket at 2in)

motor shaft to sprocket has MA of 3:8 (radius of motor shaft at 3/16in, radius of sprocket at 1/2in)

This gives us 800lbs at the edge of the motor shaft (3/16in radius) and thus at 1in out from the center of rotation of the motor shaft would be approximately 1/5 of this (3*5 = 15, ergo 15/16in) or 160 in lbs.

I would appreciate confirmation or corrections.