Topic: Drilling Brake hubs and side covers question

[The Gardener]

Some of you guys out there have bikes with drilled rear brake plates and I've seen a few drilled sprocket covers. how hard is that to do? Seeing how the covers are somewhat curved. Even using a drill press, I've had the bit want to walk on me because of the angle. What do you suggest? Attached pics of what I'm after found on wed.

[Don R]

 Use a center punch to locate the hole, pre- drill the hole with a smaller bit, Clamp the part down and go slow.

[The Gardener]

Thanks Don. Would you use a Hand Drill? I'm thinking that would allow more freedom of angle. I guess what you said, "GO SLOW" is really the answer. 

[Steve_K]

I would use something called a centerdrill.  It is short and is used to start holes in some machining processes.  I would use a drill press and bolt the thing down.  Not good if it gets away from you.  I would use a smaller drill after the center drill and then go to your final drill.  I might even drill from the inside, in case there are any ribs inside.
Steve

[Toxic]

Dewalt make a bit called a "pilot point" it's not supposed to "walk".  I'm sure all the big name manufacturers have their version.

I used a press and hand held the piece after placing some wooden blocks under it to get the drill site perpendicular to the bit.

I used a counter sink to finish it off.

Be prepared to spend alot of time covering the part with masking tape and laying out where exactly you want the holes.  Unless you are going for a total random look.

[Jim F]

you can also use what is referred to as a step drill
it steps up from say a 3/16 to a 1/2 inch in either 1/16
intervals or 1/8 intervals. You can get these at Home Depot or lowes
I use them allot when the hand drill is the only way
although I did mine on a Bridgeport mill and a few clamps