Drilling out center mount drive chain sprocket


Apr 9, 2008
I hope this isn't a duplication of another question. I searched DRILL + SOCKET but came up with a lot of unrelated stuff. Hey, it would really help this forum to have some better search stuff e.g. DRILL within 2 SPROCKET, etc. I will post this also in the appropriate place.

I would like to expand the center hole in my drive chain sprocket by 1/8" or so to accomodate the bearing dust cover (on the coaster break side obviously). Initially, in my haste, I just left the cover off on on FIRST wheel. The bearings have failed with only 300 miles on it. Not sure this was what did it, as it was an OLD schwinn wheel, but in any event, I am going to do it RIGHT this time. I must do things WRONG at least once, I think.

Before I go home and try to use my crappy once size fits all hole saw that really is for wood, although it SAYS it cuts metal (teeth are big) and wear myself out, OR try my hack alternative which would be to use a grinding stone on a drill to grind out a weird shaped increase I thought I would ask.

I am sure someone has drilled out the sprocket hole. I haven't found a dust cover this sprocket will fit over YET. At this point, I am going to buy a hole saw for metal. Any suggestions ? I have a drill and a drill press, although the drill press is for woodworking really. At a low speed, I think the drill press would be best. Is there some kind of "cutting oil" to use to keep the temperature down ?