do you turn your rotors on a lathe?

My points, its hard to explain the machine until you see it in action.

First, the surface of the hub to the rotor is left alone, so its going to stay the way it's meant to be.
Second its mounted by the lugs, not the center of the rotor bore. Simulating the wheel and the pressure the lugs cause.
Third of all it has a runout calibration, standard lathes do not. And I know that 99% of techs do a run out check by eye, not with a dial gauge on the stand-alone.
Fourth, it has an oblong cut, meaning it doesn't spiral the same speed and shape, it pulses and prevents the "record player" effect that is undesireable.

I hate setting them up, but they speak for themselves with the cut. I can get a better cut the first try on any vehicle with them, and never worry about accidental runout.

ENJOY MY PICTURE!

 

That's an awesome illustration.

 

Hey @Bebop ,
Back in the day they used to say you could only turn rotors once. Is this still common practice or does the minimal thickness determine?

 

Rotors are throw away parts these days. You can replace them for about $40 each. Not worth the hassle to have them turned when you can get brand new ones for not that much more. Also, the more material you remove from turning, the more likely they will heat up and warp. Turn 'em and you'll just be replacing them with new ones 10K miles down the road once they've warped. That's been my experience, YMMV.

 

14 minute mark. Definitely warped rotors.

You reluctant weirdos.....

https://youtu.be/unbEQOxXtjg

 

That's disc thickness variation.

That's a low spot. Easier to call it a warp though.

 

I’ve turned the same rotor multiple times before and was still within tolerance. Some vehicles have throw away rotors like Range Rover

 

What is the minimum required thickness of a 2nd generation rotor? My Tacoma is a 2012 Access Cab SR5 4x4 if this makes a difference.

 

No.

If my rotors are fucked I buy new rotors.


And no rotors don’t warp. When you drive your truck like you stole it the pads burn impressions of pad material on the rotors causing an uneven braking surface.

Replace the rotors and do the proper bedding procedures to brake them in. Also stop braking aggressively or you’ll just get the same issue again and again.

Rotors rarely warp. You have to be towing excessively, climbing mountains all the tims, or high speed race with your vehicle to build up that much heat. 99% its poor driving habits.

I will also say this... if you think your rotors are warping due to excessive heat... why would it be an intelligent idea to make them thinner?

Rotors are dirt cheap.

 

Rotors warp. Anyone that says they don't has never checked one with a dial indicator. I've seen a .015" warp before - and it wasn't pad material. If a cast iron cylinder head can warp, then rotors can, and certainly do, warp.

On-car is better for machining FWD style rotors because any runout in the hub is factored in when the rotor is machined. On old school RWD front rotors, a brake lathe was accurate because it centers on the bearing races. As people have said, with cheap import rotors, it's generally not worth the time to turn rotors anymore.

 

I honestly do not know off of the top of my head; usually it will be stamped or etched into the rotor itself somewhere.