Drilling Your Own Brake Rotors

[LarryBart]

Gent's and Ladies:

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The current host for this thread is going off-line and will not host the images or text any longer. In an effort not to lose this valuable information I have parked the Photo's with imbedded text on Photobucket and all remaining text on Proboards. In addition a complete back-up is stored on my computer hard drive as well as to a CD. ( Just In Case ).

Best Regards Larry Bart

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The Walker rotor drilling tutorial

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If you wish to save for printing any of the Photo's or drilling diagrams they are in JPG format. Hold your mouse over the item you wish to save and right click your mouse. A screen will pop-up, choose the option Save AS. The current file name you are over will show in the Pop-up screen. Using the mouse choose the location you wish to save to and click save. Now you are free to print with your favorite program.

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The Templates are made to print out at full size on 8.5"x14" paper. Then you just tape the two halves together. If you can only print on 8.5"x11" paper you will need to tape four quarter pieces together.

This is the pattern I used for my discs above

photobucket.com/albums/v114/LarryBart100/dots01.jpg [/img]




These templates are made so that you can create your own custom pattern. Just take a compass and place the point in the center, then move the lead tip out to the pre-measured dots and make your arches around the pattern.






Once you've done that, you can create your own design and try it out on paper before committing it to metal. I must have sketched up about a hundred different ideas before I drilled anything.



- Set your drill press to a slow speed of about 300 to 600 rpm.


- Cutting oil is a must, it makes a big difference in the life of your bits and how clean the holes turn out.



- Cheap drill bits will die fast. It's well worth it to buy good bits from the start.


- Common sizes for drill bit/hole sizes are 1/4", 5/16" & 3/8".
photobucket.com/albums/v114/LarryBart100/RotorDrill08.jpg [/img]


photobucket.com/albums/v114/LarryBart100/RotorDrill09.jpg [/img]


photobucket.com/albums/v114/LarryBart100/dots01.jpg [/img]

No matter what hole size or pattern you choose just make sure the hole size and pattern overlap to allow the entire brake pad area to be swept.
(see diagram below)


Here are a just a few of the others that came I up with but didn't use.
One Dot



Two Dots


Three Dots


Four Dots


Five Dots


Six Dots



24 Spaces 4 Holes




24 Spaces 5 Holes



2 Spaces 4 Holes



2 Spaces 5 Holes



40 Spaces 4 Holes



40 Spaces 5 Holes







All coments Welcome

[mental]

You know Larry, I am constantly amazed at the amount of effort that people on this board put out just to help others. That is SO COOL. Thank you.

Mental

[LarryBart]

AW SHUCKS '

[Walker]

Larry,

If ya want, I can burn the whole HTML thing, images, graphics and all to a disc and mail it to ya if you like. Or, if you like I could FTP the whole thing as well.

Walker

[LarryBart]

Walker:

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I sent you a private message


LarryBart

[LarryBart]

Hi Folks :

The one piece of information I was not able to extract from the posting on Brake Drilling, or from the postings of those of you who have drilled there rotors already and I would like to add this information to the body of the text for those of us who wish to drill our rotors is this.
What size Drill Bit did you use ?
I know there will be different answers from different folks however I would post a range of sizes already used.

Thanks in advance Larry Bart

[steve78650]

I used a 1/4", but I think if I did it again I'd use 5/16". Granted, I could enlarge the existing holes, but I wouldn't pull my rotor just for that...Next time!

[Polamnus]

1/4" here too, but AFAIK as long as you're in the same neighborhood, the functional difference should be negligable

FWIW, don't mess with anything but carbide bits. Even using lots of cutting oil, I destroyed used up one brand new carbide bit per disc.

Best,
Pol

[rube]

I used the template at liberalredneck.org/techfiles/XS650rotors/
as a guide.
I only used every other hole though, and used a 1/2" drill bit. I like the look of bigger holes and wanted a lager percentage of the swept area to have holes than on the template.
I have not mounted and tried the brakes yet, but I'll post follow up.
I used a Bosch bit ("titanium" I think, about $15 at Lowes). I first drilled 1/8" pilot holes, then 1/4" holes then the 1/2". I used a lot of WD40 and silicone spray when I ran out of WD40. I chamfered the holes on both sides with a chamfering bit.
I like the way it looks. I'll post about how it works once I get the new wheels set up.

By the way, does anyone know the size and length of the 6 mounting bolts that hold the disk on the wheel? I was going to get new hardware rather than take the old wheel apart.

If my link works here is a photo of my drilled disk.
tinypic.com/3hq8z


-Aaron

[slide]

I will be drilling my discs very shortly and appreciate the patterns. I plan on using a 3/8" bit but from what I have researched previously I am lead to believe that the holes should not be champferred, rather just cleaned up for a sharp hole to catch the gasses. Please provide your thoughts and expertise. Thanks.

[gdjohnson]

I've been told not to champferred the holes as well though no reason was given. For my yellow bike I used the swirl pattern with 7 holes in each of 6 arms for the front rotor and 6 holes in each arm on the rear rotor. After I finished both rotors (1/4" holes) I used a large 1/2" bit (not a drill bit but a cone shaped bit used in a die grinder) in a cordless drill to clean up the edges of the holes without doing any cutting. The next step is major cleaning to remove all the oil on the rotors and in each hole. I used thinner in a shallow tray followed with brake cleaner spray and lots of wipes.
Greg

[arkansawyer]

I used a 1/4" bit but made my own pattern and templates from posterboard. I only made a small pattern, not the whole disc. The pattern had holes in it that matched up with the bolts holding my two piece rotors together. This way every hole was in the same place as the one opposite on the rotor so it won't be unbalanced.
I used my $90 delta drill press set on the lowest speed and lots of cutting oil. I used to work in a machine shop so I know how to sharpen a drill bit with a bench grinder. I used a bosch titanium bit. It's gold colored and much better than carbide. I just barely chamfered the holes with a larger bit. The idea is to just remove the burr, not to make a taper.
My pattern is a swirl, but with the swirl going to the outside of the rotor, not tapering back to the center.
The bolts that hold the rotor to the wheel are 8mmX1.25 thread. I can't remember the length but I think it's 30 or 40mm. I'll measure mine this week and post it. Stainless allen heads this size are over a buck each, but they're so pretty.

[Walker]

The size of the hole doesn't matter, just as long as the holes and the pattern overlap enough to sweep the entire surface of the pad.

The reasoning behind leaving the edge sharp, is so that the holes edge is able to sweep the brake pad free of metal bits and other contaminants.

Walker

[arkansawyer]

My bolts that hold the rotor to the hub measure 30mm long.
The thing with chamfering isn't to make a tapered hole. It's to remove the burr that a drill bit kicks up. The rotor surface should be flat, no protrusions.
Yes, the whole advantage to drilling is to sweep trash from the surface.

[50gary]

I thought that I read once that the sharp edge of the non-chamfered hole is also better for the initial bite of the brake pads? Some newer rotors have swirl or angled grooves for out gasing and bite. The gases released from the pads as they heat actually lift the pressure of the pads from the rotor. They aren't drilled through at all. Cheers, 50gary