Misterg
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- 1,522
- Location
- North Wales
A hub for an auxiliary pulley to fit inside the existing crank pulley / harmonic damper:
It was cheaper to buy a ready made 6 groove pulley than it was to buy an aluminium blank to make one (also, I would have *really* struggled to machine a 150mm diameter pulley on my mini lathe!) Just needed to machine the existing hub out, leaving a register on one side to centre it on the new hub.
Turning the OD of the new hub took some weird setups on a mini lathe - it just doesn't have the cross slide travel.
The ID of the crank pulley needed to be cleaned up to remove some pressing marks and true it up. I tried for a while to set it up to run true in the 4 jaw, but gave up and machined a mounting flange for it instead. (All I had in a big enough piece was some 16mm tooling plate.)
Once bolted up to the flange, the pulley ran true and the inner face cleaned up very quickly.
The new hub was a very nice fit.
Next was to bore out the front of the hub for the mounting bolts, with a lip to suit the register left on the new pulley. It was a lot of swarf!
With the new pulley registered against the hub it could be held in place while I used my toolpost spindle to drill the holes for the mounting bolts through the pulley and into the hub (only one initially, then all the others when that one was in place). The indexing was done by eye to lines scribed concentric to the large holes in the pulley.
With it all still in the lathe, I could clean up the ID on the new pulley. The hub mounting holes were made after removing it from the lathe (just matched drilled on my pillar drill using the crank pulley as a template).
After degreasing and anodising:
Assembled pulley:
Looks the part, at least...
It was cheaper to buy a ready made 6 groove pulley than it was to buy an aluminium blank to make one (also, I would have *really* struggled to machine a 150mm diameter pulley on my mini lathe!) Just needed to machine the existing hub out, leaving a register on one side to centre it on the new hub.
Turning the OD of the new hub took some weird setups on a mini lathe - it just doesn't have the cross slide travel.
The ID of the crank pulley needed to be cleaned up to remove some pressing marks and true it up. I tried for a while to set it up to run true in the 4 jaw, but gave up and machined a mounting flange for it instead. (All I had in a big enough piece was some 16mm tooling plate.)
Once bolted up to the flange, the pulley ran true and the inner face cleaned up very quickly.
The new hub was a very nice fit.
Next was to bore out the front of the hub for the mounting bolts, with a lip to suit the register left on the new pulley. It was a lot of swarf!
With the new pulley registered against the hub it could be held in place while I used my toolpost spindle to drill the holes for the mounting bolts through the pulley and into the hub (only one initially, then all the others when that one was in place). The indexing was done by eye to lines scribed concentric to the large holes in the pulley.
With it all still in the lathe, I could clean up the ID on the new pulley. The hub mounting holes were made after removing it from the lathe (just matched drilled on my pillar drill using the crank pulley as a template).
After degreasing and anodising:
Assembled pulley:
Looks the part, at least...
