Gears for NEMA17

http://goods.ruten.com.tw/item/show?21403085454477
http://goods.ruten.com.tw/item/show?21302075887733
http://reprap.org/wiki/NEMA_17_Stepper_motor
Holding Torque應該是指靜力矩
各種力矩單位轉換

http://www.thingiverse.com/thing:41876
http://www.thingiverse.com/thing:8460
http://www.thingiverse.com/thing:20884

http://search.ruten.com.tw/search/s000.php?searchfrom=goodsheadbar&k=%C0%BD%A5X%BE%A6%BD%FC