How to Turn a Rotor on an Ammco Brake Lathe

[@writtenpieceopaper1]

Thank you for posting this! This is almost exactly the method they used at my school on the Ammco 6900 and 6950. The only 2 differences are they make us put the band even for the scratch test and hold sandpaper grit 130 after the last cut. The teacher goes fast so we all get a turn to practice but you explained it so well and here I can always go back and rewatch what I didn't understand. Thank you again.

[@richardspaulding5035]

Thanks for the kind words; Not many shops use these lathes anymore. They would rather sell the customer those cheap rotors made in China. I think a resurfaced original equipment rotor is far better. I am retired now, I only work on friends and family vehicles these days. Quick tip: If your having problems with vibration try making the tool work a little harder. Take .006" per side on your Finnish cut instead of .004" This works especially well on larger rotors. I never take less than .004 because it will cause the tool to overheat. Thanks for watching my channel.

[@danfield8102]

Another awesome video Rick! I didnt realize how much went into resurfacing rotors, but your are correct the OEM rotors are much better than most aftermarket stuff. Thanks for the awesome job on the rotors for my Sierra, I installed the resurfaced rotors with a set of Akebono brake pads and the brakes are smooth as a baby's bottom.

[@richardspaulding5035]

Thanks Dan. It is like anything else the more you put into it the better the results.

[@danfield8102]

@@richardspaulding5035 I may need you to turn another set of rotors for me on my car, if you are willing. Is there a way for me to contact you directly?

[@richardspaulding5035]

@@danfield8102 Drop them off any time Dan. I am home most of the time these days. We can exchange numbers then. I don't want my number going out over KZbin LOL. Remember to blow your horn before getting out of the car. I have two German Shepherds now. I look forward to seeing you again.

[@gregorysampson8759]

This is great! I want to come spend the day in the garage with you!

[@richardspaulding5035]

I am in southeastern Ma, if you are ever down this way please by all means contact me

[@kathyd1050]

Thank you. This was very helpful.

[@richardspaulding5035]

Not many shops do that anymore, glad the video was helpful.

[@SWTWHITEGSR]

Excellent video! Thank you for this video.

[@richardspaulding5035]

Thanks for the kind words and thanks for watching my channel

[@jeffd3844]

Thank you for posting this. Being in the Rust Belt, do you have any experience with coated rotors? Some are painted, some appear to be annodized and some have some other kind of anti-rust treatment/coating. I wonder how well they prevent rust and "sticking" to the hub.

[@richardspaulding5035]

I have never worried about them being treated with paint or anything else. I usually will put Anti-seize on the hub before installing them. Rust will form on the disk part of the rotor overnight in almost any climate. As you apply the brakes the pads work the rust. If you have ever let a car sit for a week you will hear noise as the pads work off the rust. The rust being rubbed by the pads actually makes the cast iron rotors harder. This is an old machinist trick used when rebuilding an engine block. After boring the cylinder walls, they put the block outside for several days to let it get good and rusty. Then bring it in and work the rusty cylinder wall with a cylinder hone. It hardens the cast iron and makes the rings last a lot longer.

[@ZZTOPGUY1]

What would happen if you cut a rotor below the discard thickness but run it anyway?

[@richardspaulding5035]

As you know the caliper piston moves outward to compensate for brake pads wear. The manufacturer calculates the discard thickness of the rotor by determining how thick the rotor needs to be to prevent the caliper piston from completely blowing out should the brake material on both pads wear down to nothing. So, to answer your question initially nothing would happen. However, once the brakes were to wear down beyond a certain point you run the risk of a failure. Thanks so much for that question as I am always looking for new content. I am going to produce a new video on this subject in the days to come.

[@ZZTOPGUY1]

@@richardspaulding5035 thanks for the reply. I found this video because I am currently looking for a used brake lathe. I’ve had to replace warped rotors so many times over the years that it would have paid for the machine by now. Nobody in my area wants to turn them anymore and I wondered how far they could be turned under the minimum thickness before you would have problems.

[@richardspaulding5035]

@@ZZTOPGUY1 I purchased my lathe on Craigslist, as I recall I paid 800 dollars for everything including all the adaptors.

[@ZZTOPGUY1]

I’ve been looking on marketplace. So far everything has been too expensive or way too far to drive. I’m seeing a lot of on car brake lathes. Do you have any experience with those?

[@richardspaulding5035]

I have never used one. From what I understand they use them with cars that have problems with runnout for reasons other than a bad rotor, Say you had a hub or axel that is causing the runout. An on the car lathe will tune the rotor to the car's components.

[@richardspaulding5035]

DAN If you read this I somehow lost your last comment about this video. If you can please by all means re send it.

[@rolandos64]

Where are OEM rotors made?

[@richardspaulding5035]

I am not sure these days. Some of the good ones were made in Canada at one time. The cheap ones on eBay are made in China. Some of the rotors from your local parts store are made in Mexico.

[@rolandos64]

I’m guessing all the rust dust is why technicians opted for replacement rotors over saving its consumers money and inheriting a lifetime or medical bills and problems

[@richardspaulding5035]

If the dust is the only concern a mask can be worn. The issue is the high cost of labor as most shops get $100 to as much as $150 per hour these days. It takes 35 to 40 minutes to resurface a rotor. It does not make sense for them to do so. They not in business to save the customer money they are in business to make money. I am retired now and enjoy saving my friends and relatives money. I picked up the machine on the cheap because the shops don't use them anymore.