I found this picture somewhere on these message boards (can't remember were): http://www.geocities.com/maglight2000us/index.html and was going to implement this same design for my machine. But I'm not entirely sure how it works. When the acme rod is rotating, how exactly does the roller bearing react from each side? I'm assuming that the inside of the roller bear moves while the outside is stationary. If that's the case, then is the roller bearing pressed fit inside the wood counter bore? Can someone explain how this works?
By using one bearing on each side pressed into the MDF, the nuts closest to the bearings on the screw hold it in place and adjust the end play, the second set of nuts are used to lock the setting on each side, and there is a Lovejoy connector (spider coupler) connecting the screw to the motor. The bolts and rods are just spacers for aligning the motor to the screw and setting the spacing (between the end of the screw and the end of the motor shaft) for the lovejoy connector.
I put my motor assemblies together and I noticed If I tighten the two screws that press against the bearings it restricts the movement considerably. In other words it's hard to turn by hand. Only if I barely hand tighten it does it then turn easier. Is this right? Will my motors have trouble turning my ACME screws? I'm using Nema23 269 oz. in. motors by the way.