Yeah, this isn't something I'd try in my garage, or even hand over to my "buddy"
My understanding, and believe me I don't really know any of this for sure, but I had some rotors drilled many years ago, and this is what I remember being told:
1. The holes need to be perfectly spaced and centered. The rotor needs to be balanced, just like the wheel and tire. If it's off, it'll get funky on you.
I also remember hearing something about if the hole pattern is wonky, it might create some kind of harmonics when braking at speed. I don't know if that's total BS or not, it's just something I remember...
2. The other thing is that these discs are made from really hard metal; so be prepared to pay big money for the right drill bits, or go through just as much money burning up the wrong ones...

I really DON'T want to fool around with my brakes willy-nilly; that's why I started this post. I want to be sure this guy really knows what he's doing, and that's if I do this at all....

I was pretty sure the "Harmonics" thing was Phooey, but like I said, that was something I was told. I've never really seriously researched the pro's and con's of drilling a disc, or the possible safety issues. Call me shallow, but I've always just thought it looked cool.

I've been tossing around this idea, and the idea of replacing/upgrading the whole front brake on my Vintage Roadster project, but the truth is, I really like the look of the stock rotor; it's sleek and slim. Anything I would upgrade too would be a big PITA, and would look heavy and clumsy on the bike, and truthfully, I think keeping the rotor solid, and un-drilled will look more true to my projects 1960's-ish flavor, so I think I 'm just gonna leave alone!

Good to know...
I've heard more than a few here complain about it not being strong enough, but my bike will be significantly lighter than stock by day's end, so I think I'll be alright. I've got a stainless steel line and brand new EBC pads for it. If I really hate it after I've gotten it on the road for a while, then I can look down that road.
In either case; I'm not sure that the drilling alone really improves the performance all that much. I'm guessing it might keep the rotor just a wee smidge cooler; it would help shed water in the rain, but it also reduces the surface area....

If anyone knows anything about the performance advantages of having drilled discs, please chime in! Surely there's a reason that race guys started doing it...

teabowl13 wrote on 12/15/11 at 09:15:31:

I've heard them say it improves braking... but like you said... too many holes will reduce effectiveness.

My take on it, the holes keep the pad surface clean.  And will slightly increase brake pad force (smaller contact area, same force)

But it looks cool...

Alright-y Mister! I look forward to seeing what you come up with.
Maybe I'll send you my disc along with my cam chain tensioner...

I like a curved pattern, one the drops the 2nd ( & each next) hole toward center enough that it doesnt sweep any of the area the first one did as it passes thru the pads, narrow as the swept surface is, that mite make for a 3 hole pattern. Thats just my eye, I doubt that it matters,,

None of the holes will sweep the same area.

I measured the disk, but forgot to measure the pad.

So... jog... more arc in the pattern?