They Like It
Parametric timing pulley by Erik is licensed under the Creative Commons - GNU GPL license.
© 2009 by Erik
Instructions
Below are the parameters in the beginning of the OpenSCAD file.
// //////////////////////////////
// USER PARAMETERS
// //////////////////////////////
// Pulley properties
shaftDiameter = 8; // the shaft at the center, will be subtracted from the pulley. Better be too small than too wide.
hubDiameter = 22; // if the hub or timing pulley is big enough to fit a nut, this will be embedded.
hubHeight = 8; // the hub is the thick cylinder connected to the pulley to allow a set screw to go through or as a collar for a nut.
flanges = 2; // the rims that keep the belt from going anywhere
hubSetScewDiameter = 0; // use either a set screw or nut on a shaft. Set to 0 to not use a set screw.
numTeeth = 20; // this value together with the pitch determines the pulley diameter
toothType = 3; // 1 = slightly rounded, 2 = oval sharp, 3 = square. For square, set the toothWith a little low.
// Belt properties:
pitch = 5; // distance between the teeth
beltWidth = 4; // the width/height of the belt. The (vertical) size of the pulley is adapted to this.
beltThickness = 0.65; // thickness of the part excluding the notch depth!
notchDepth = 1.8; // make it slightly bigger than actual, there's an outward curvature in the inner solid part of the pulley
toothWidth = 1.4; // Teeth of the PULLEY, that is.