Ive got a friend with a machine for turning brake rotors but he has never done X-drilled/slotted before. Are there any certain procedures/precautions that need to be taken to do these correctly? Im going to need to do my front brakes soon.

 

If the brake lathe is multi speed turn the rotors at the slow setting and only make small cuts.

It would not hurt to clean out and chamfer the cross drill holes before before and after you cut them too.

 

Tony: one of the rare few that knows how to work on real cars.

 

Its also helps to have worked at an auto parts store for years where I cut hundreds of drums and rotors.

It came in handy when I cut the porsche rotors when I did my last brake job.

 

i worked at a brake place for a wile and did crossdrills and slotted all the time wile i was there, along with my own. ever sence then it pisses me off that people refuse to cut them becouse they dont know how and cant bare to admit that the customer could accaully know more then them.

 

i was always told no you cant and you have to have the right machine (like some special pixie dust). so i guess the only machine you need is with one that has variable speeds which a lot of shops have.

now youre saying take off about .003mm at a time on the lowest setting? that would take forever...
please tell me the increments you have to do them in...

 

You can do a fast deep cut on the high end ridges that are on the undrilled areas, but when it comes to cutting over the holes I would recommending not going over 2 thousands.

You can do more per cut but it will be a lot harder on the cutting mechanism.

 

wouldnt the rotors crack from the cross drilledness

 

I can show you hundreds of small superficial thermal stress cracks on my cross drilled rotors, but its overall structure is OK.

Its all about venting the braking surface, so I look at them as additional vent area.

 

i just dont want my rotor to shatter. i need new ones any ways. if there was a service limit on mine they would be well passed.