Cutting HTD pulley(s)

[Ricardoco]

Hmmmm looks interesting....Did you find all the dimentions somewhere Jonathan, or did you use some math trick and work it all out yourself?

Rick

[Jonathan]

Cambam has a plugin that draws 5M HTD pulleys, so I used that. However I did check it looked reasonable first by looking up the equations, which are very simple. You just find the pitch diameter (30*5/pi) and subtract a constant to find the PCD of the holes, then subtract a different constant from the PCD to find the external diameter of the pulley. Draw all those and round off the corners for each tooth, like this:



It was a similar procedure for the program I wrote to mill XL pulleys, but those were a bit more interesting since the tooth profile has to be milled, not drilled.