homemade BB chaser?

Discussion in 'Cycling Equipment' started by Ant, Jan 25, 2003.

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  1. Ant

    Ant Guest

    I will be painting a frame sometime in the next couple months. I will likely want to chase the
    threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?

    my idea was to take an old steel BB cup, put a fat bolt through it and nuts tightened down on each
    side of it, weld a handle on as a crank, and then carefully mill grooves into it, perpendicular to
    the threads (and clean them up as necessary), to allow the chips a place to go. would it work? would
    it not be aggressive enough? am i asking for trouble?

    anthony
     
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  2. S. Anderson

    S. Anderson Guest

    Well, it might work. You can do a fair job with a small wire wheel and a dremmel tool to clean most
    of the paint crap out actually. You can even carefully clean the face of the shell with a file or
    sharp knife to get rid of paint. I've done this when I knew the threads and shell were in good shape
    and parallel and it works fine. Not high-tech, but if you're in a pinch, it'll do.

    Cheers!

    Scott..
    --
    Scott Anderson

    "ant" <[email protected]> wrote in message
    news:[email protected]...
    > I will be painting a frame sometime in the next couple months. I will likely want to chase the
    > threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?
    >
    > my idea was to take an old steel BB cup, put a fat bolt through it and nuts tightened down on each
    > side of it, weld a handle on as a crank, and then carefully mill grooves into it, perpendicular to
    > the threads (and clean them up as necessary), to allow the chips a place to go. would it work?
    > would it not be aggressive enough? am i asking for trouble?
    >
    > anthony
     
  3. ant wrote:
    > I will be painting a frame sometime in the next couple months. I will likely want to chase the
    > threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?
    >
    > my idea was to take an old steel BB cup, put a fat bolt through it and nuts tightened down on each
    > side of it, weld a handle on as a crank, and then carefully mill grooves into it, perpendicular to
    > the threads (and clean them up as necessary), to allow the chips a place to go. would it work?
    > would it not be aggressive enough? am i asking for trouble?

    I've done this for damaged threads, but it's not necessary for just paint.

    Go to the hardware store and buy a cylindrical wire brush designed to fit into your electric drill.
    The typical item for this is about 3 inches long, about an inch in diameter.

    At the shop I keep one of these permanently chucked into an old, cheap high-speed 1/4" drill. Stick
    it in from the right side of the bb and zzzzzz the paint right out without removing irreplaceable
    metal from your BB.

    Sheldon "Learned This Trick From Francis Bolag" Brown
    +--------------------------------------------------------------+
    | The holy passion of Friendship is of so sweet and steady | and loyal and enduring a nature that
    | it will last through | a whole lifetime, if not asked to lend money. --Mark Twain |
    +--------------------------------------------------------------+ Harris Cyclery, West Newton,
    Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
    shipped Worldwide http://captainbike.com http://sheldonbrown.com
     
  4. Yup, many years ago I made a BB thread chaser from an old pitted set of BB cups and I'm still using
    them. You need both cups if your BB has British or ISO threads since one side has right hand threads
    and the other side has left hand threads (as my bikes do). I believe that Italian threads are right
    hand on both sides as are French. I took a hacksaw and made a cut perpendicular to the threads into
    both sides of the cups, starting from the inside and going about 2/3 of the way accross. The cup was
    so hard that I had to heat the places where the cuts were to go red hot with a propane torch and
    then let them sit in the air until they were cool. This softened the steel enough that I could cut
    it with my saw. This process puts two slots perpendicular to the threads and when you screw the cup
    in the edges of these slots clean and chase the BB threads. The rust, paint, grime, whatever comes
    up through the slots. Works very well. I can't say whether it works as well as a real thread chaser
    because I've never had one of those My homemade one works well enough that I've never considered
    buying a real one. One other tip: You might need to spread the slots slightly by tapping a blade
    screwdriver into them. (Put the cup with the outside down on your workbench and put the screwdriver
    blade into the slot and tap downward. A blade screwdriver tip is tapered so the further you tap it,
    the more youll spread the slot. Don't overdo this. I think I used the homemade chasers without
    spreading at first but after some use the slots got narrowed up a bit.) I just turned my chasers
    into the BB with regular BB cup tools.

    One final thought: Why not put masking tape on the BB threads before you paint? It would still be a
    good idea to chase the threads but some tape would minmize the amount of of paint to be removed
    (likely there would still be some rust or crud to be removed.

    Good luck, Bob Taylor
     
  5. I assume you want to chase the threads because they will be covered with paint. If this is the case,
    why not just cover the threads with grease before painting? Wipe it off when done. Ernie

    ant wrote:

    > I will be painting a frame sometime in the next couple months. I will likely want to chase the
    > threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?
    >
    > my idea was to take an old steel BB cup, put a fat bolt through it and nuts tightened down on each
    > side of it, weld a handle on as a crank, and then carefully mill grooves into it, perpendicular to
    > the threads (and clean them up as necessary), to allow the chips a place to go. would it work?
    > would it not be aggressive enough? am i asking for trouble?
    >
    > anthony
     
  6. Paul Kopit

    Paul Kopit Guest

    Why not grease the threads and put stoppers on each end of bb. Use a powerful solvent like methylene
    chloride to get any paint that may have gone in off. I screw in an old, steel bb cup to make sure
    the threads are smooth. If they are not, go to a local shop and have them chase and face.

    On 25 Jan 2003 17:26:08 -0800, [email protected] (ant) wrote:

    >I will be painting a frame sometime in the next couple months. I will likely want to chase the
    >threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?
     
  7. You're going to an awful lot of trouble just to keep paint out of the bottom bracket threads! Why
    not just install a pair of bottom bracket cups into the frame prior to painting? Afterward just
    remove them and all should be well.

    --Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

    "ant" <[email protected]> wrote in message
    news:[email protected]...
    > I will be painting a frame sometime in the next couple months. I will likely want to chase the
    > threads afterwards, and was wondering if anyone has ever made a homemade thread chaser for the BB?
    >
    > my idea was to take an old steel BB cup, put a fat bolt through it and nuts tightened down on each
    > side of it, weld a handle on as a crank, and then carefully mill grooves into it, perpendicular to
    > the threads (and clean them up as necessary), to allow the chips a place to go. would it work?
    > would it not be aggressive enough? am i asking for trouble?
    >
    > anthony
     
  8. Ant

    Ant Guest

    "Mike Jacoubowsky" <[email protected]> wrote in message
    news:<[email protected]>...
    > You're going to an awful lot of trouble just to keep paint out of the bottom bracket threads! Why
    > not just install a pair of bottom bracket cups into the frame prior to painting? Afterward just
    > remove them and all should be well.

    Thanks for the replies, folks. In truth, I never really intended to paint my bb threads. I mentioned
    painting because another thread was dealing with chasing after painting. (i was going to mask it
    off, but greasing the threads in addition sounds like a good idea)

    But i do want a thread chaser, amd it sounds like it could work, so im goign to make myself a lh/rh
    pair out of an old bb. the wirebrush method sounds excellent for normal cleaning.

    thanks

    anthony
     
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