I’ve finally reached the point in bicycle maintenance where I embark on procedures that only seasoned mechanics often thread–I mean tread. One of these is chasing and facing bottom brackets.

For those of you who don’t know what a bottom bracket is, it’s the part of the bike that holds the crank. On new frames, the threads that hold it in place need to be prepped (aka, chased) and paint on the outside of the shell needs to be removed (aka, faced) for proper installation of today’s external bottom bracket cups.

These procedures are usually performed by expert bike mechanics due to the potential damage to the frame, as well as the cost of tools involved. Unless a rider buys new frames on a regular basis, it’s best just to have a shop prep the frame.

Considering my rotating stock of bikes and interest in bike building, it made sense to invest in tools for these procedures. Plus, I had an old frame that I could practice on. I decided to get the Ice Toolz Bottom Bracket Tapping/Facing tool, which at $175 is significantly cheaper than the $650 Park Tool version.

I first tried the chasing/facing procedure on an old Gary Fisher MTB frame. Things went easier than I thought. OK, now for the legal disclaimer…don’t try this at home! Seriously, I’ve been working on bikes for about 5 years now and learned a good deal about mechanical and metal work during shop in high school (aka, I ran out of advanced chemistry classes). These procedures are best left for an experienced mechanic at a bike shop–unless you talk me into doing this for you.

I next decided to prep a Blue CXC frame that I got last year, but never properly built. Here are some photos demonstrating the steps:

Here’s the the unprepped bottom bracket shell.
Note paint on the outside of the shell.

The first step is to insert the tapping/chasing tools.
Turning these as the same time clean the threads
and make screwing the bottom bracket in easier.

The next step is to use the facing tool
to remove the extra paint. This took a
great deal of time, but makes the
bottom bracket cups line up better.

Here’s the finished frame. Please note the nice
shiny surface where the paint has been removed.