Makerbot Y idler support

This is a piece I built to support the Y idler pulley on my Makerbot.

As shipped, the Y idler on the Makerbot is just a plastic pulley on a bolt screwed into the baseplate. This is really not a good design. The baseplate can flex, which makes it hard to properly adjust the belt tension. The pully is bare plastic turning on a fixed metal axle, without even a bushing, and can after a while get very noisy.

This modification adds a bracing arm which attaches around the end of one of the Y rails, using the same hex nuts that hold the Y rail end cap on. You will have to use longer screws to account for the thickness of this piece. Two bearings are pressed into the piece, and these now support the 4mm bolt that the pulley turns with. This makes the Y stage much quieter and smoother, and makes it easier to properly adjust the Y belt tension.

Warning - this is an experimental piece and may require some trimming to fit properly, some of the clearances are really tight. This is up