100633 MakerBot Replicator 2 Aluminum Carriage

This seems to be the only replacement I've found for the Makerbot Replicator 2 carriage replacement, so I had to make it work, and I did... barely.First, the rail bearings don't snap in like the original, so there's a set screw for each one that presses on the lower part of the bearing side, keeping it fixed in the carriage. If the set screws are in too far, carriage will bind toward the left and right. If too loose the carriage won't be stable vertically. Tighten the set screws just enough that the carriage can't move vertically, yet still can move smoothly all the way to left and right. I'd also suggest using a dab of super glue (or Loctite) on the screws to keep them from working loose.Second, and of more concern, is that when the extruder was attached, the nozzle was beyond the height adjustment range of the build plate when I tried to do the gap adjustment.The mounting surface of the extruder is too high relative to the bearing seating surface. To accomodate this flaw in the carriage design, I had to extend the extruder tube a full turn further into the mounting block. As a result, the top nut on the tube doesn't fully engage all of its threads on the tube. So, it's under more stress.It works fine after all that, but if I had known of an alternative, It wouldn't have been worth all this trouble. I would have returned it in a heartbeat.

Well built and fits just right.