Utilizing the proper a_Radius at the pitch line, the diameter of one of the (ten or so) rollers determines
the b_radius for the slightly curtate curve traced by the innermost point of one of the rollers,
as well as the b_radius for the slightly prolate curve traced by the outermost point of the one of the rollers.

Modifying the script to compute these two points as a pair, for each t_radian distance, and
then creating a diameter circle there, will create an envelope.
Maybe make the circles planar surfaces.
There will be t * 2 * PI * number of circles, but MoI should handle this easily.
Then boolean add the circles to create the envelope, (?)
And boolean deduct the envelope from a rectangular rail, to form the upper portion of (some of) the teeth. (?)

? - Brian