MakerFarm i3v adjustable Y idler

Tried http://www.thingiverse.com/thing:612584, did not like. It was awkward to assemble and knocked about 10mm off my Y travel.

This is as simple as adjustable gets. Put a couple M3 nuts in the forward slots. Ideally, you'd leave a couple of 10mm M3 set screws in, but I don't have any handy.

I use longer M3 bolts, tighten down the belt, then lock the M5 bolt (with extra washers on the bearing sides to avoid rubbing) and remove the M3's so my Y travel isn't restricted. So far it hasn't budg