Anybody turning rotors on a regular lathe?

[ovilla]

Just wondering if this could be done. I know that brake lathes come with all of the needed adapters but it's still just a lathe. Anyway, just wondering if anybody was doing this with their lathe yet and was having any success with it. Or, has anybody figured out how to make a home made brake lathe to just turn rotors (no drums)? Thanks

P.S. For now, I just take my rotors to Pep Boys. Anyway, I'd love to have an actual excuse as to why I need to buy a used lathe. Been seeing a ton of these on craigslist lately so it's got me thinking a LOT.

 

[nate379]

Sure you can do it with a reg lathe.

 

[fordcragar]

You'll need a lathe that can turn at least a 14" diameter piece.

 

[70Chevy]

My Dad turned our rotors all the time on his lathe - quick and free!

 

[Falcon67]

I've talked to people that have done it - the trick is to be sure the setup will let you flip the rotor side-for-side and have it be in the same orientation to the cutter. Otherwise, the sides of the rotor won't be parallel. A pair of bull nose centers that fit the bearing races comes to mind. You should be able to do an 11" rotor on a 12" swing lathe, provided the carriage/tool holder will cover the required surface area.

Paying $20 at a shop to have them cut your rotors still makes sense even if you own a $3000 Grizzly, IMHO.

 

[weicm3]

do you guys normally turn rotors? why not just replace them. it costs not much more than the labor for turning it. some car markers also suggest not to turn their rotors and they should be replaced when they wear down to a certain level.

 

[tdkkart]

I've done it, it's not the same as a brake lathe but it can be done successfully.

You should be able to do an 11" rotor on a 12" swing lathe, provided the carriage/tool holder will cover the required surface area.

This is the trick, I have a 12" lathe, and have done 11" rotors, but getting the toolholder out to the outer reaches can be tough.


A couple years ago a stock car racer friend of mine needed a new rotor for the rear of his hobby stock type car. Being a used car with a Ford rear that was, as most are, adapted for disc brakes he didn't know for sure what he needed for a rotor. After much searching, none of the "standard" rotors used for this application were right. Close, but not close enough with re-doing all of his bracketry. More searching, and he finally came across a guy that knew what he had.
Apparently the rear had been converted to disc many years ago, before it was real common. What they had started with was an older Impala FRONT rotor. Obviously, using this front rotor meant that the entire center portion, the part that the bearing races are pressed into, had to be removed.
Dummy me, I volunteered to do it. There was ALOT of cast iron that had to go away. I got it done but it took way too long. I'll bet I removed 4-5 pounds of material from that rotor, all to make something very close to what could be bought off the shelf.
I also learned that brake rotors are not real quality pieces. This was a brand name parts store rotor. The original casting was so far out of wack there was no way that it would have been balanced when put on a car.

 

[crankshaftdan II]

Turning rotors on a regular lathe is a good idea as long as you do not exceed the mininum thickness, most rotors today are the cheepo (made in china) versions and are considered, throw-away. Unless you are paying $60.00 + for a single rotor, you get what you pay for and can expect for them to wear out rapidly. Most of the cheepo ones are destroyed by the road salt and don't have much stock to turn anyway. They have to be parallel after turning and I have had brand new ones that were warped off of the shelf or were turned by the mfgr. on a defective lathe. Just my two cents worth

 

[z28snksknr]

My $0.02 on brake rotors:

Used to work at a large auto parts chain. We had a fair amount of rotors get returned for being below the min. allowable thickness. Pissed alot of our commercial accounts off because of that. Our commercial manager started tell them "when the customer comes back, just tell them that they need to replace the rotors again- that's more buisness for you". He soon after got demoted back to a parts counter guy.

 

[rsanter]

its easy to do
you have the lathe
make a set of bushings & mandrel like you see a brake lathe use
set it up to turn on centers
works great

bob

 

[Possum]

Last set of new rotors I purchased were .045" over the minimum limit. That pretty much makes them one time use.

 

[Falcon67]

Last set of rotors I bought were China source and they ran $50 each - way more than having them cut. unless something bad happens, I usually get 2 surfacings out of a set of rotors. Usually. The china rotors have decent faces, it's the bearing race pockets that are all over the place. One set drives in smooth, then next rotor requires a torch, frozen races and a sledgehammer.

 

[nate379]

$20 to turn a set of rotors or at least $40-50 per rotor to replace, and on some vehicles easily $100 each. Doesn't make too much sense to buy new ones to me if the old ones just need to be turned.

do you guys normally turn rotors? why not just replace them. it costs not much more than the labor for turning it. some car markers also suggest not to turn their rotors and they should be replaced when they wear down to a certain level.

 

[A_Pmech]

My local auto machine shop charges $5 a piece to turn them on a brake lathe. At that price, it isn't worth the trouble.

 

[Blackend]

O'Reilly will turn individual rotors for $8 a pop off the car....if you have an O'Reilly store near you.

 

[E.rodz]

have also done this is works well if you lathe is big enough.I used a old axle and just bolted the rotor to it in the lathe. you just have to make shure the axle is not bent before you use it.

 

[OldCarGuy]

I've been turning both rotors and drums on my lathe for yearsw. A good setup using an indicator in a sturdy lathe will do a good job. But it hard to beat the $5.00 price. A few years ago the local Action Auto Store would turn them free with the purchase of the pads.

 

[T VETTE]

do you guys normally turn rotors? why not just replace them. it costs not much more than the labor for turning it. some car markers also suggest not to turn their rotors and they should be replaced when they wear down to a certain level.

Repair vs replace cost, and condition of rotor is my rule of thumb. A light clean up and the integrity of the part likely is 90% of new at a fraction of the cost. I will usually not turn an aftermarket rotor, only OEM .

Any cracks or blue hard spots I toss it.

 

[bazzateer]

As long as the rotor (brake disc) fits then should be no problem.

 

[ovilla]

do you guys normally turn rotors? why not just replace them. it costs not much more than the labor for turning it. some car markers also suggest not to turn their rotors and they should be replaced when they wear down to a certain level.

I like to use brembo rotors on all of my cars (Porsches, Honda Ody, and my Maxima) since they tend to hold up well and not warp much. That is, as long as I'm always careful about checking the torque settings after the tire shop does a rotate and balance. Anyway, brembos cost a bit more ($75-$100+ each) for my cars but I can always get them turned once and sometimes even twice.

 

[Busted_Knuckles]

The last shop I worked in, got its brake parts from Napa. The Napa aftermarket composite rotors have gotten soooo bad, the parts store would cut the brand new rotors, before delivering to us, to get them "true". About 1 in 3 sets of rotors we would get new out of the box would need cutting, of course you would only find that out after installing them and driving the car. Nothing like installing new **** parts twice and get paid once. Most the boxes said china or india on them.


Now that I work from home, Ive been buying Raybestos top of line (they have 3 levels), they are still imports but at least they are straight. I picked up a rotor lathe at a farm consignment auction last February for $80!, in good working condition. Ive also picked up some Kent Moore / GM adapters for their composite rotors, so they are pre-stressed before cutting. Haven't used them yet, but Ive got a 1500 and 3500 GM 4x4s, so I thought they would be handy to have. I see them on ebay pretty regularly.

 

[rsanter]

I dont have to turn rotors very often so I sold my brake lathe.
I can turn them on my Lathe if I need to.
keep in mind its not about saving the small fee a shop would charge, many shops will overcut a rotor or drum and can ruin an otherwise good part in order to save time verses having to take a second cut.

bob

 

[Busted_Knuckles]

I bought mine for convenience and control as to what is and what is not undersize, more than anything else. Got tired of "your .005 under", cant cut them. Ive seen rotors run down to just one quarter of the rotor, that is to say, the inside missing, the cooling vents gone and just the far outside still present, and of course the pads are long gone, metal on metal, but actually stops pretty well. Not advocating breaking safety rules, but when 7/8s of the meat is still there, junking rotors for a couple thousands is just not economical. I don't do that on others rides, just my own, and my fleet is large enough that it does matter me.

 

[sanddrag]

It's only about $6 to have them turned at the local shop here, worth it over getting new ones or doing it myself.

 

[69lm69gp]

Ok this is about drums but it have some mounting ideas.

http://www.wewilliams.net/docs/1936 - How to True Brake Drums Bulletin No 4A.pdf

 

[buildyourown]

I just turned my old rotors down into hubs last night for a brake upgrade project I'm working on.
If you were refacing rotors, you need to be a decent machinist with decent tools to get parallel faces and acceptable runout.
It wouldn't be that hard, but having the right tooling for the lathe would be good.