Summary

This is a brace to stiffen the X axis for the Printerbot LC. In the current design of the LC, belt tension causes the X bridge to warp. This brace is designed to counteract the warp.

See comments on thing 30954 for motivation for this mod.

Instructions

Print out "stiffener part 1 minimal.stl" and "stiffener part 2.stl". I printed with 100% infill in abs for strength. "stiffener part 1 alternate.stl" is meant to replace the X stepper mount with a part that accepts the threaded rod. It is more experimental and I have not used it, but thought it might lead to ideas by others.
Obtain a 1/4x20 threaded rod that is roughly 9 inches long. Put a bolt on each end a couple inches down the end of the threaded rod.
Check that the threaded rod goes into the holes on the two parts - may need to enlarge the holes so that the threaded rod just slides in. I used the threaded rod as a file.
Attach "stiffener part 2" to the X belt pulley by removing the nut on the pulley shaft, pushing the nut into the part, and reattaching so that the hole for the threaded rod points toward the stepper motor.
Put the threaded rod with "stiffener part 1 minimal" on one end into the hole on "stiffener part 2"
Place "stiffener part 1 minimal" on the plywood part that the X stepper is bolted to. There is a protrusion that the part fits over. I intended this part to bolt on using the existing screw, but ended up just breaking that off the part with the hole and allowing the pressure to hold it in place..
Adjust the two nuts on the threaded rod to apply pressure and spread the mechanism so that the X pully shaft is square with the bridge and the bridge no longer warps.

Printrbot LC X Axis Stiffener