This is a redesigned motor bracket for the Mendel Y axis, intended for use with ball chain. As the ball chain gear needs to be fixed to the end of the NEMA17 shaft, and the NEMA17 shaft is shorter than the standard Mendel Y Motor Bracket is thick, this version has a recess for the NEMA17 to fit into, allowing more shaft to protrude.

The ball chain cannot negotiate tight corners, so the idler on the motor bracket is abandoned and a 608 bearing with fender washers (M8x25 is good) on each side is used as a pulley to guide the chain to the deposition bed. A similar pulley arrangement now takes the place of the Y Idler Bracket, which is no longer required.

The motor is raised up so that the chain or belt will not clash with the M8 bracing, and no idler roller is needed.

Print and use. You may wish to see if additional washers need fitting between the bracket and the first fender washer, depending on the length of the shaft on your NEMA17. If using ball-chain see http://www.thingiverse.com/thing:2009 for the gears.

Attach the chain to the deposition bed using pieces of hosepipe or metal strip screwed down tight from underneath.

Be prepared to adjust the tension as ball chain has a wearing-in period.

The mendel_misc.inc file is found here:
http://www.thingiverse.com/thing:2192