Using Atlas Lathe to Turn Rotors

jumbojak · May 14, 2026

It's an Atlas 12" lathe and the rotors are a badly worn pair from a JD Gator. What are my chances of success with HSS tooling? Before anyone says to replace the rotors, they're over $300 a piece.... This machine is badly busted. Struts and ball joints are already on the way so at least I know I can fix that issue.

The rotors could really use a fresh surface and our regular machinist is ******* with gocart shenanigans at the moment. I'm thinking about at least trying a light facing cut on the ridge to see how that goes and if it cuts well maybe trying to true up the whole face.

JuncleJohn · May 14, 2026

Can’t hurt to try. Worse thing to happen is your tool bit will wear before you finish your cut. Welded carbide tool bits are pretty inexpensive. That’s what I’d use if I didn’t have insert tooling.

John

Steve from Socal · May 14, 2026

I would try to preserve any thickness if the replacements are more than you want to spend. Grooves or ridges? If the rotor is OK exceptfor a ridge on the OD then yea turn away. Just grooves in the rotor, don't take more material off just to make the surface smooth.

alfadan · May 14, 2026

Slow speed and slow feed.

gte718p · May 15, 2026

If it fits, it ships.

Turning brake rotors is not rocket science. What Alfadan said go slow. It probably will kill the tooling so resharpen often.

Personnally I would go with carbide.

IndyGarage · May 15, 2026

I've found it difficult on a conventional lathe. A brake lathe typically cuts both sides of the rotor at once, which balances out the cutting force.

Getting a flat, right angle face on just one side at a time takes an extremely rigid setup - which is probably not going to happen on an atlas lathe - worth a try, but I tried and I didn't have good results.

rattle_snake · May 15, 2026

My lathe is too small for rotors. I've used a flap wheel take the lip off and break glaze. Of course a bus full of nuns will die at some point
These were junk yard parts 28mm out of 28mm nom.

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larry4406 · May 15, 2026

I might have been that bad guy that installed new pads and let them wear into the pre-grooved rotors…

alfadan · May 15, 2026

On my silverado, the Bosch disks only had a rust ring around the outside lip and only a half thou under brand new thickness! I was amazed, as I've put about 50k on it with some fair towing. I just kept them going.

cannuck · May 15, 2026

Wouldn't even try with a small lathe. You can't take a "light" cut as you need to dig under the extremely hard skin. Need extremely rigid tool, post, cross slide and carriage and even then almost impossible with single point too as the cutting force will distort the rotor. See if you can find someone with a disc lathe - you will be happy if you can.

jumbojak · May 15, 2026

cannuck said:
Wouldn't even try with a small lathe. You can't take a "light" cut as you need to dig under the extremely hard skin. Need extremely rigid tool, post, cross slide and carriage and even then almost impossible with single point too as the cutting force will distort the rotor. See if you can find someone with a disc lathe - you will be happy if you can.

That's my worry. I got caught up trying to get the parking brake working today and that'll probably eat up the rest of my allotted time until the struts come in. Unless the shop next door opens up in time I'll probably just ship it with new pads once it's safe to drive.

I will have to cut some new slide bushings for the parking brake caliper to make it functional again. So a bit of lathe time is still in order.

jumbojak · May 15, 2026

IndyGarage said:
I've found it difficult on a conventional lathe. A brake lathe typically cuts both sides of the rotor at once, which balances out the cutting force.

Getting a flat, right angle face on just one side at a time takes an extremely rigid setup - which is probably not going to happen on an atlas lathe - worth a try, but I tried and I didn't have good results.

Yeah, it's probably not worth the effort. I'm not even sure if you could mount these rotors in a brake lathe. They have a weird shape and the "hub" appears to be integrated into the rotor with the bearing packed in behind. So whatever cut you make would have to sneak in behind the hub surface, and it's pretty tight.

jumbojak · May 15, 2026

gte718p said:
If it fits, it ships.

Turning brake rotors is not rocket science. What Alfadan said go slow. It probably will kill the tooling so resharpen often.

Personnally I would go with carbide.

I'm still waiting on drills and center drills for the Atlas. If I asked for carbide, they'd probably tell me to buy it myself if I needed it that badly....

jumbojak · May 15, 2026

JuncleJohn said:
Can’t hurt to try. Worse thing to happen is your tool bit will wear before you finish your cut. Welded carbide tool bits are pretty inexpensive. That’s what I’d use if I didn’t have insert tooling.

John

I'm imagining a spectacular crash... Broken change gears.... Flying rotor.... It'd fit well with my department!

PCustoms · May 15, 2026

These are your rotors or a paid job?

jumbojak · May 15, 2026

PCustoms said:
These are your rotors or a paid job?

I'm a junk mender for a company. Hourly pay to raise the dead, in many cases. Last year I rigged the vacuum actuated choke to a hand pump on a completely worn out Suzuki Carry so some of our guys could keep it going for just a little bit longer.

It worked out okay until they decided to stop releasing the vacuum on the hand pump after it warmed up. I carried the corpse of that truck into the woods when it finally wouldn't start anymore on tractor forks.

Maybe this time they'll check the oil before the light turns on.

jsaw · May 15, 2026

IndyGarage said:
I've found it difficult on a conventional lathe. A brake lathe typically cuts both sides of the rotor at once, which balances out the cutting force.

Getting a flat, right angle face on just one side at a time takes an extremely rigid setup - which is probably not going to happen on an atlas lathe - worth a try, but I tried and I didn't have good results.

Depends somewhat on the thickness. Granddad triet to resurface rotors off a Cessna airplane . They were around 1/4" thick. He told me that being so thin that they flexed enough that He could not hols tolerance.

I doknow guys that have successfully turned thicker automotive rotors

JuncleJohn · Saturday at 12:25 AM

We’ve done many rotors, drums and flywheels on our Clausing engine lathe. Not as efficient as a brake lathe, but we always get it done.

John

rust in the eye · Wednesday at 9:16 PM

Couldn't these be done at automotive machine shop, or perhaps a decent parts store that still has a brake lathe and someone who can operate it correctly?
WTF are (ostensibly small) brake rotors for a light weight vehicle so expensive? No aftermarket for these?

JuncleJohn · Wednesday at 10:58 PM

Automotive machine shops are few and far between these days. Most have closed due to retirements and cheap imported parts.

John

Chipm · 2026-05-21T07:19:13-0400

JuncleJohn said:
Automotive machine shops are few and far between these days. Most have closed due to retirements and cheap imported parts.

John

Our local Oreillys turns rotors.

DaveAndStuff · 2026-05-21T08:17:20-0400

It has been my experience, that many places will not touch questionable rotors

Using Atlas Lathe to Turn Rotors

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