this one

thingiverse

Customized version of http://www.thingiverse.com/thing:16627 Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=16627 Instructions Using the following options: m3_dia = 3.2 additional_tooth_depth = 0 no_of_nuts = 3 nut_angle = 120 pulley_b_ht = 13 additional_tooth_width = 0 profile = 11 pulley_b_dia = 25 m3_nut_hex = 1 teeth = 17 motor_shaft = 10 m3_nut_depth = 2.7 m3_nut_flats = 5.7 nut_shaft_distance = 1.2 idler_ht = 2 retainer_ht = 2 retainer = 5 idler = 5 pulley_t_ht = 11