Tool of the week: cable guide holder

Brazing small parts onto steel tubes is one thing; stopping them from moving around is another.

That is why jigs and guides take a lot of guesswork out of positioning parts to be brazed, because once it’s brazed on… a bit of effort required to make adjustments.

One such spot that is a bit challenging to braze on is top tube cable guides for externally routed cables.

Stylistically found on older frames to route entire lengths of housing through, the cable guides need to be straight and concentric for smooth cable entry.

So, how to ensure the guides are brazed in such a position?

The guides need to be held in place somehow and not move during brazing from a combination of the torch flame, heat, filler rod flow among other factors.

Another thing to consider is the holder not physically impeding the guide from being heated to adequate temperature to flow the filler rod, and vice versa prevent the guide from overheating and/or burning.

With a variety of methods attempted, we came across what we presume to be how the Bundys did it, and took inspiration in revamping it.

Quite an ingenious idea to braze a section of a quick-release skewer axle to an old Terrys pump clip! The clip clamps the top tube firmly enough without moving around, and the addition of the quick-release skewer axle’s 5mm diameter provides a snug fit inside the cable guide to hold it down against the top tube. The portion of skewer axle also acts as a heat sink to prevent the cable guide from overheating.

However, preliminary experimentation brazing reveals it to make heating somewhat of a challenge. Or just user error.

With the original Bundy contraption looking a bit tired and the spring of the clip no longer holding, Quang decided to take inspiration from their idea and make a new one.

He turned down a section of steel rod to 5mm, gave it a slight chamfer on the end to stop sharp edges and insert more easily into the cable guide.

Then the rod was brazed onto another Terrys pump clip with bronze, to prevent the filler melting and the rod moving during cable guide brazing.

And of course, to assure the cable guides are lined up, a simple scribe line across the length of tube section acts as a visual guide – but always check by eye too.