Back in 2012 I built a MakerGear RepRap Prusa i2 and three years late the idler block broke! I made a new one, and here it is. I'm reasonable sure no more than one other person might need this, but it's here for you if you do.

This was previously shared on another web site but that site has become unreliable so now it's here. Mainly for posterity. Hopefully you've got a modern printer and can safely ignore this part.