I thought about chucking my wheels in the lathe a few times. Not to make them smaller but to cut the outer surface so they are not so slick, new wheels need to break in before they get good grip
Done tons of wheels in the past on lathes, never had to freeze them or anything though that obviously works in making the material easier to work with.
For some things just a file works good, rounding the lips, breaking the wheels in, cutting grooves, removing excess coning. You CAN even do flatspot removal but there’s complications there making it not ideal and more difficult, for the most part file’s for when the wheels are concentric and balanced without a ton of material to remove.
Cutters are what you’d want for removing material to reduce the diameter. But that’s where things get more technical. Unfortunately I don’t have any insight as to the cutter profile we had, but I do know it was custom made for the task.
What we did was had a piece that went in the head stock which was a press fit for the bearing seat, and an insert which went into the bearing seat on the opposite side with a little bit of a looser press fit, which had a center hole in it which supported the bearing with the tailstock. That worked really well.
I would guess that High Speed Steel would be better than Carbide, since HSS is sharper but IDK, we never tried any carbide.
@Skunk I did a set of 97mm wheels in the lathe at work a while back - had to take about 5/16" off the inboard side of the back wheels to get them to clear the belts.
I used a HSS tool ground with a sharp positive rake (maybe 30 degrees?) and a very sharp edge. Cuts urethane like butter - the trick is to take a fairly deep cut and use a pretty high feed rate, to keep the chip thick - if you slow down the feed it’ll heat up and start getting gummy and melty. You don’t have to freeze them unless you want to take really shallow cuts - then the urethane can get pushed out of the way by the cutter rather than being actually cut.
The main issue is holding them without deforming them or letting them wobble. Chainmaillekid above has the right idea - you don’t want to chuck on the thane itself, ideally you want to only hold onto the core.
If you use dry ice, a trick to really improve its ability to transfer heat is to make a bath of it with acetone. Be super careful though, that shit is like icy napalm - way more dangerous than liquid nitrogen because it sticks to skin and soaks through fabric rather than beading up and rolling off. It will give you almost instant frostbite and freezerburns.
(and, once the acetone warms up, it’s still flammable as hell too.)
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All my HSS bits I had were ground to a specific profile that wasn’t suitable. tried the carbide on a junk wheel – worked great so I didn’t try anything else
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Speaking of rubber on a lathe, I saw an amazing video a few years ago that I can’t find now - Big orange rubber roller (from a paper mill maybe?) being turned down on a lathe. Maybe 2-3ft in diameter, 10ft long. The rubber chip was flying off the lathe and arcing into a trash can about 25ft away in a single unbroken (probably miles-long) piece.
I came across a post by moe where he used cetrax on his drives, wonder if the same thing could be done with belts
probably, just needs the pulley farther from the wheel. I just see how he attached the gear to wheel. @MoeStooge can you enlighten us?
Might of been one of these methods.
I tried that, didn’t work for me. The wheel was too soft, the drill bit would wander with any down pressure at all. Maybe I just did it wrong. Also, the gears I was working had the mounting holes too close to the core, so the bit would wander into the core.
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@Skunk just do what I did. Give them to a slider and let them slide them down. He gets the enjoyment of sliding to his heart’s content, and you smaller wheels.
I’m expecting to be doing some straightening sanding when I get them back though.
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I’m not waiting for someone to ride my 107mm down to 90mm.
And I’m not risking uneven wear from someone sliding them down that low.
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Those are called the limited edition cone 107s.
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