Results 1 to 5 of 5
  1. #1
    mtbr member
    Reputation: mack_turtle's Avatar
    Join Date
    Jan 2009
    Posts
    2,776

    drilling a DIY fixed cog

    cold wet weather is getting to me...

    I read a DIY article on 63XC about making fixie cogs for your disc hub and thought I should try it. I went out and bought a cobalt bit today to drill out a 16t cog from a 7-speed cassette to fit on my disc hub to fixie-ize it. I nailed the cog to a work bench so it would not move, dripped a little oil on the cog to serve as cutting oil and went to town. after ten minutes of pounding at the cog at varying speeds, i barely scratched the cog.

    so what am I doing wrong here? is the bit crap, or is it my technique? I would just buy a Tomicog but I don't know what size I would want and I don't know if i'll even like riding fixed offroad. I don't have $35 to just toss out the window on a gamble.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2010
    Posts
    239
    Riding fixed offroad is fun for certain trails and for scenery riding. Give it a whirl. For gearing, do one or two cogs less than you would do on a SS.

    As for technique. You'll ruin your bit soon, don't worry. Hand drills will absolutely not work. I've tried multiple times with multiple cobalt bits. I've been told that a drill press with a really low RPM setting might get the job down with the same cobalt bit.

    Word of advice? Just buy a TomiCog or cog from VeloSolo and sell it later if you don't like it. It'll save you a lot of time, it'll be perfect and it'll have resell value.

  3. #3
    mtbr member
    Reputation: mack_turtle's Avatar
    Join Date
    Jan 2009
    Posts
    2,776
    damn. I'll see if I can find someone with a drill press or just save my pennies for a Tomicog. or does anyone want to sell me one?

  4. #4
    .......
    Reputation:
    Join Date
    Apr 2007
    Posts
    3,707
    What kind of bit did you use? I've drilled through some tough stuff with some ti bits.

  5. #5
    mtbr member
    Reputation: mack_turtle's Avatar
    Join Date
    Jan 2009
    Posts
    2,776
    it was a Hitachi cobalt bit. it was about $4 at Home Depot.

    It has been suggested that I try starting with a center drill bit, but if i spend more money on tools, i might as well cut my losses now and just buy a Tomicog. that would have happened by now but I am unemployed and bored. it was a struggle to justify springing the $4 for the drill but. I have a job interview next week, wish me luck, for my sake and the sake of my more mutilated bike.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •