Bored, 4am, 2 more hours to go before I'm off for the holidays, curious about what to do with spare parts laying around my garage... Can a DIY'er with a drill press and a jig cross drill his own? If yes, how would he do it right?

C'mon 6am...

 

i wouldnt attempt it. i would be too worried about cracks forming, and other stuff just not being right.

 

the good ones are forged with the holes in them, not drilled. drilling will cause stress cracks to propagate.

 

I drilled a set of worn out Turbo S rotors several years ago as a test to see if it would help braking. This was for a track car. At the time, cross drilled turbo S rotor were really expensive and I wanted to see if it would be worth the cost to buy cross drilled over solid rotors.

I would not do it again. Took forever to drill all the holes. And I did not really notice any improvement in brake performance, cooling, etc. And they did crack through pretty quickly (I knew they would). What was interesting is that one rotor was an OEM, the other was a Zimmerman rotor; the OEM rotor held up much better and had smaller and fewer cracks than the Zimmerman. Ive since confirmed this with others, that there is a difference in quality of the OEM vs the Zimmerman.

Anyway, I would guess that home made cross drilled rotors would last for awhile in a street only application, but the significantly greater pressure and heat of track life, kills them fast.

 

Actually, I'd take blanks over x-drilled rotors 6 days a week and twice on Sunday. Brake rotors are heat sinks and you are removing both surface area and mass - not a good thing from my perspective and certainly not a means to combat heat. I believe this concept of forged/cast-with-holes is a misnomer, they are drilled afterwards and chamfered (sp?) to prevent stress risers. I do not believe any manufacturer is producing a rotor today that is cast or forged w/ holes in it for the mass marketplace. Another advantage to blanks is that they can be turned, I do not believe you can turn a x-drilled rotor (and yes, I would use a machined rotor on the track). If I recall correctly, the original purpose of providing escape was for pads that out-gassed - the slots and/or holes provided an escape so it would not form a layer between the rotor and pad. I also believe it is used on motorcycles for weight reduction (don't know that I buy it is for wet/rain as I have heard previously).

 

I dont see why you couldnt turn a cross drilled rotor, you would have to take thin cuts but not impossible

 

Dirlled rotors can be turned. Also, one of the things that driling/slotting does is remove the gases, but it also helps clear the pad from contaminents, wear material, etc. Most brakes are sufficient heat sinks and if they are borderline, the cross drilling won't make much difference.

As for driling your own, it's probably not worth it based on time, let alone safety.....

Matt

 

Cast rotors with the holes cast in them are the best.

all you have to do is look to what Porsche is selling it's top of the line cars with.

And Adam - the holes actually INCREASE the surface area. and they do help with cooling.

but drilling them yourself is a waste..

 

I crewed with Larry Schumacher at Sebring for the 12 hrs. when they tried non drilled/cast rotors. They had less pad wear and the rotors looked great after 12 hrs of abuse.

Alan C.