Hobbing a Pulley for driving accessories for Model Steam Engines or Toy Steam Engines

[Jim Dobson]

Hobbing a Pulley for driving accessories for Model Steam Engines or Toy Steam Engines
This worked out really well for a first attempt, I've been wanting to try this for ages to stop belt slippage on pulleys and drive wheels when running accessories off steam engines under load which can very often be a problem as some engines lack the power to be able to put a lot of tension on a small round drive belt.
It’s a great hobby and pastime working on your metal lathe or metal milling machine making parts for model engines and model or toy steam engines.

 

[Jim Dobson]

Here's some photos of a vertical transmission that I made some years ago that I have 'retrohobbed' one side of the drive pulleys on this morning.

 

[Jim Dobson]

Retro Hobbing.....(Worm Gearing) I've been busy hobbing my vertical and horizontal transmissions I made some years ago plus a few other accessories.
Things I've learned from doing many now - what works for me.

Lathe 400rpm
Use lots of WD40 and a toothbrush to keep clearing away the chips
Very critical is to have the tap centered perfectly in the middle (spend some time eyeballing this) if there's any chatter whatsoever the tap is either trying ride up or down
Don't put too much pressure on the tap, its not needed and just keep going in a couple of thou at a time. When you're at the depth you want, let the piece rotate at least another 4x for a really clean cut.

 

[Jim Dobson]