Tuesday, 19 April 2011

Brazing a brake-arm clip for an X-FD drum brake

Warning!: Ghetto, probably unwise, metal work below.

My Stowaway build includes a Sturmey Archer X-FD 70mm drum brake in the front wheel. Drum brakes have a long reaction arm which have to be secured to the fork in someway to provide a fixed point for the braking action to react against. This is usually done by using a clip-on fastening that is available in a variety of sizes, or the simplest way is to use a hoseclip (this is how my Sachs drum brake is attached to my Nexus bike). But since the Stowaway was stripped of paint anyway it made sense to install a permanent brake-arm clip on the fork. I'd already had my first go at welding with the Hopper, so this time it was a chance to have my first go at brazing.

This is not exactly the high-quality methods that will be employed in full-scale bike building to say the least, but the end result is good enough for me in my garage. Kudos go again to my brother who showed me how to do this using a canister of Mapp gas (ment for plumbers fitting copper piping) with the nozzle tightened slightly to get a smaller flame. Still, by brazing standards the flame was big and ugly, heating up a much larger area than needed - which is why the braze spreads so far. In anycase, brazing is such a nicer process to do than welding, mainly because you can take your time and fuss less with awkward gloves & face masks.

Here's a quick run down & a video

A small tab, just the right size to fit the X-FD brake arm, made out of a piece of scrap bracket.
Start heating it up
Beginning to melt the first bit of brass into the gap. Given up on the crappy mole grips by now, they kept falling off from the heat.

Decent amount of braze on there now
The brazed clip after a bit of filing
Fits nicely & when all painted up this is a much more elegant solution to securing the reaction arm than the alternatives.


  1. The brazing looks pretty tidy, and it'll look like factory finish once it's all painted and stuff.
    It takes me back; I haven't done any brazing in almost 20 years... :-)

  2. Just what I was looking for. I plan to do the same for my bike. As you say, a more elegant solution. I will do the same for the rear roller brake too.

  3. Just did mine, quite easy.