Is that supposed to be a T5 belt profile? I've never seen a timing pulley with a 'tit' on the tooth crest.
Is the tit on the pulley teeth from wear, or is it some substance that got in the belt tooth valley groove and stuck to the teeth? And that's what you're cleaning?
To clarify, here's a T5 belt profile from Misumi. I think the groove is there to help air escape at higher speeds (noise reduction).
Last edit: 5 months 3 weeks ago by spumco. Reason: Add pic
The dark line in the middle of the tooth is just the last bit that still has the original surface, with a bit of dirt that makes it darker. On both sides, it is mostly obliterated. I assume that is what you mean by “tit.”
And I think the gap between the teeth is also to reduce the smallest possible bending angle, in addition to the reasons you listed.
I got completely turned around looking at those pics the first time. I thought the surface you were resting the belt on was actually the pulley teeth in mesh with the belt.
