After some calculation as to the http://www.engineersedge.com/calculators/torque_calc.htm calculator for bolt torque I came up with an almost unbelievable small amount of torque needed for the Z axis steppers. It is amazing how efficient a screw mechanism can be. So,to lift 10 lb, I only need 0.5 lb/in or 8 oz/in torque (0.5 lb / in = 8 oz / in). Similar goes for the VAT tilt, but adding to that gravity and I did not even make an effort to calculate it, I have just used lower spec motors that follow:
a 25 to 35 oz/in ( estimated by comparison – could not find docs for this particular model ) from a printer
no idea what this stepper is rated at (estimate is about 70 oz/in) , but if it fails for the task I will replace with the 180 oz/in on hand.
I ran into a few useful goodies at the local flea market:
a small NEMA17 stepper and an all important Emergency stop button from Fuji Electric.
The Stop button is of fantastic quality. It is barely used. How many times have you had to push the Emergency stop on daily basis? I hope to never use it, but if the need should arise, it is there.
How many fingers am I holding up?!
After some consideration I have made a small correction in the corner (gussets) bracket location.
As you can see the bracket that holds the cross-member rail for the projector was moved to the top. I have discovered some flex in the joint and it was eliminated that way.
Also, as seen in the picture above, I moved the bracket from the outside to the inside, facing the projector, giving me longer movement of the projector all around.
To get a little more maneuvering room under the projector I raised the entire frame on 4 bolts ( like stilts), but you can use other, equal height pieces you find around the house.