I decided to make full use of my FlashForge Creator Pro bed so I combined the arm and motor mount into one piece. Then I laid it horizontally on the bed which makes the arm much stronger, and because I eliminated the connection point it is lighter too. Since I had four Ipower out runners (iBM 2217Q) motors laying around I made holes for that motor. If you have a FlashForge Creator Pro just use the correct files. Note:12/19/14 I have strengthened the arms with a couple of bands (not that any ever broke. I also created one without mounting holes for those that have different kinds of motors.