Shop recommendation to cut rotors?

[Mick]

Anyone know a place local to Somerville that can cut rotors?
Looking for someone who can work with 2 piece rotors and will do it right, not just throw it on a lathe and hack off material.

Thanke'

[boltonite]

Try German Performance Service, 26 New St. Cambridge, MA 02138 Phone (617) 349 2993, they (marc) will know. Owner used to work for Turner, he's a racer and did a lot of their race fab and machining (tell him I said hi).
FF

[962porsche]

mick the best way to cut the rotors for racing is an on the car brake lathe . when ever we get high end cars in our shop for a brake job thats how we do them . it makes the rotor 100% true on the car .

[Mick]

Try German Performance Service, 26 New St. Cambridge, MA 02138 Phone (617) 349 2993, they (marc) will know. Owner used to work for Turner, he's a racer and did a lot of their race fab and machining (tell him I said hi).
FF

Thanks Fred.
I called and spoke to Mark. Strange conversation. He was really short with me and didn't seem interested in the least, and said even if he were he wouldn't do it anyway.

[boltonite]

In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc. This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures.

- Quoted from http://www.stoptech.com/tech_info/wp_wa ... disk.shtml

If you contact them again pretend you don't know me, maybe that will help.

[breakaway500]

I agree 100% with 962porsche about cutting rotors on the car.It is the only way to ensure a perfectly perpendicular surface to the axle.
I disagree with that Stoptech article concerning warped rotors.I have seen this posted numerous times,and it still amazes me.
Can I be the only one who has personally seen physically warped rotors? Hundreds of times over? I know it is not unevenly deposited pad material because I have turned down these warped rotors,and that is NOT brake pad material coming off the rotors as they cut on the machine.It is iron.Lots of it.Sometimes the rotors are out of specs by over .030! That sucker is bent,and it needs to be replaced.
Up to about .005" distortion,I will take a cut,if the rotor has not been cut before,UNLESS you are expecting 100% from your brakes,and then I will suggest new rotors.

If the rotor is not warped,rusted,grooved or worn to a taper,I will reuse them,and just deglaze them with a DA sander,and 220 grit,then 320 grit,followed by a soap cleaning. 98% of the time,I replace rotors. They can be pricey in some applications,but what price do you place on your brake performance?
If on the car turning is not available,and the rotor is suspected untrue,I would replace it.

[Mick]

If you contact them again pretend you don't know me, maybe that will help.

I didn't have a chance to mention your name before I was dismissed ..It probably would have helped.

I don't believe the rotors are warped. There is a slight pulse in the pedal that could probably be taken out with a scotch brite pad. But, I do have some grooves starting to develop from funky pad ware, so I thought I'd bring them someplace and have them do a light hone before I fit fresh pads.

I disagree with that Stoptech article concerning warped rotors.I have seen this posted numerous times,and it still amazes me.

In the case of Stoptech I think they're referring to two piece vented rotor design, which are much less likely to warp than a non vented OE rotor.

[breakaway500]

Mick,Stoptech really did not specify in the article,however,I have seen one piece,two and three piece rotors warp. I honestly do not understand how Stoptech can stand behind tha statement that all rotors with runout are not warped,but instead,have pad residue built up,causing the runout. I have seen rotors come off looking like potato chips! If the iron gets extremely hot,is not supported or is cooled unevenly,it can warp. You can clamp a bar or screwdriver (in leu of a runout guage) close to the surface of your rotor and spin it to see if there is excessive runout.Usually,if you can see runout,it is excessive.More than .003" total runout is usually noticable on the pedal. More than .005" is downright scary feeling.

[boltonite]

I have seen this posted numerous times,and it still amazes me.
Can I be the only one who has personally seen physically warped rotors?

The reason for quoting this again is sort of a joke, TMS (where Marc worked for many years) and StopTech have a close relationship. -FF

[962porsche]

any tech will cut god knows how many rotors working on cars every day .last week alone i did 3 drake jobs !working for race teams i have seen alot of rotors with pad build up from heat transfer . but never with a street driven only car . what you need to look for when your cutting the rotor is a very fine small thin ring around the warped spot in the rotor . they are very hard to see some times you may have to take the rotor off the lathe and catch the ring in the light . an other way to tell is by looking at the face of the pad . look for pucks that would be small peaces of the pad missing . if your using a racing pad then you want about 800 to 1000 rotor temp. some people don't like drilled rotors but if the drilling was done right they are ok and good for cooling the face of the pads . after you come in from the track and the car is sitting for a minnet or two roll the car so the pad and rotor is not over heating one spot .

[offcamber09]

Mick, we'll either hack off a bunch of material or do a light hone- whichever you want. The investment necessary for a proper on the car lathe with all of the adapters (especially if you are dealing with many different makes) is tough to justify in this day of disposable rotors. Fresh bits and the right guy will get you a good usable cut.

[962porsche]

the cost of the adapters is not that much and there are not that many deferent bolt patterns so the 10 that the lathe came with have worked out quight well . the lathe paid for its self in less then a year . if the rotor cost more than 40 dollars the best thing to do is cut them if you can . i just cut a set for a 911 today . it did 2 things one got me the job and two saved the car owner money . i think i would call that a win win ????

[cuda6666]

Disposable rotors are the way to go. Subie guys should contact Eric at http://www.brakeswap.com