Topic: Brake rotor chamfering

[onetruepunk87]

Ok, so I'm probably opening up a can of worms of "what kind of oil is best" proportions, but what are the pros and cons of using a chamfer on drilled rotors. From what I've read it's a very divided issue. I chamfered the holes when I drilled my 750's rotor, not by much, just enough to deburr it and lose the sharp edge. I just drilled out the rotors I'll be using for my CB500 and will most likely chamfer them too. What's everyone else doing on theirs?

CB500 Rotors



CB750 Rotor

[70CB750]

Here is some info for you:

http://www.sp-performance.com/Ad-Drilling.HTM

but I used just a drill bit to chamfer mine.

What they say seems to make a lot of sense, but for our bikes it would be hard to collect any data to support any theory here.  Not sure about 500, but the 750 disc is very, very solid; Honda built that like a tank.

[Rocky2010]

Wedged a piece of wood in the centre of disk then use compass to find centre, cover the face of the disk with bearing blue then mark out the holes with dividers scribing arc for appropriate hole centre and pattern Scribed marks are more visible when the bearing blue is applied.
Centre punched hole centre marks then drill small hole first then go back around and drill final hole size then use a larger drill  to chamfer holes.
Once that is done wipe off bearing blue and job is completed.

[BeSeeingYou]

Since there seemed to be pro and cons for either method I came to the conclusion it doesn't really matter.  I did not chamfer the holes in my discs for the sole reason it was less work.  It has not caused any problems.

[onetruepunk87]

I just did mine with a countersink, it should take off some of the sharp edge plus I think it just looks cleaner. But, to each their own.

[onetruepunk87]

Thanks!