Hobbing a Brass or Aluminium Drive Pulley to Stop Belt Slippage

[Blue HeelerParticipant @blueheeler]

I’ve posted up photos before of hobbed pulley drives. It’s a process that works very well and gives a professional result (very similar to what Wilesco does on their drive pulleys). I’ve done well over a hundred brass and aluminium drive pulleys now.

Here’s a vid I did a few years ago of the process –

[John HaineParticipant @johnhaine32865]

Yes, S.O.P. to hob teeth on the filament drive “pulley” for DIY 3D printers.

[egaParticipant @ega]

Interesting as I have just made pulleys for the UPT minidrill; they are of steel, however, and don’t seem to slip.

I wonder what effect the hobbing has on belt life?

I watched the OP’s video with captions and was intrigued by his “three-door truck”!

[bernard towersParticipant @bernardtowers37738]

My UPT is 40 years old and the belt hasn’t slipped yet!

[Michael GilliganParticipant @michaelgilligan61133]

I think the difference is that the little engines use small diameter pulleys and low belt tensions … decidedly sub-optimal … they need all the help they can get.

MichaelG.

[bernard towersParticipant @bernardtowers37738]

I would have thought that it was all relative as the UPT is 1/4″ dia belt on approx 2 1/2′ pulley and the small engines my grandson has use 1/16″ belting on pulleys approx 3/4″ to 1″pulleys.

[Michael GilliganParticipant @michaelgilligan61133]

That ^^^ may actually be the difference then, Bernard

1/16” belt is much thinner than Blue Heeler typically uses

MichaelG.

[bernard towers]

On bernard towers Said:

My UPT is 40 years old and the belt hasn’t slipped yet!

So, approximately, is mine but I have only recently completed the mini drill!

[Mark RandParticipant @markrand96270]

My Taylor Hobson model C engraver uses 7/64 PU belts. I haven’t noticed any slippage. What it does have, like UPTs, Quorns, BCAs etc. is sufficient belt tension. Without that, round belt’s gonna slip.

[Nigel Graham 2Participant @nigelgraham2]

Since hobbing using a tap gives a shallow worm-wheel effect, would it tend to try to push the belt sideways?

Might light, straight knurling be better, although possible only on a flat-belt pulley?

Perhaps the real answer is in the matching of power, belt, pulleys and belt tension. I’ve seen light knurling on the pulleys on small model engines, whose conditions of use are outside the designer’s control; but not elsewhere.

(A toothed-belt is a diffferent matter, used for definite angular relationships.)

[Blue HeelerParticipant @blueheeler]

Here’s some pics of pulleys that I have hobbed –

[Blue HeelerParticipant @blueheeler]

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