January 2015 Posts

Columbus XCR Audax Frame

Columbus XCR Audax Frame

This is to be my first use of the BikeCad program and also to incorporate a bike fit into the design, making it my first truly custom frame. The program certainly revolutionises the design processes allowing you to constantly adjust the design whilst keeping an eye on the aesthetics and geometry. We wanted a full stainless steel frame with accommodation for mudguards and a lightweight pannier rack. The only stainless fork blades available are Reynolds 953, but the frame will be in XCR. The steerer tube has to be non stainless, from Columbus. Apart from the fork crown, it will also be my first fully fillet silver soldered frame.

Make Your Own Framebuilding Jig

Make Your Own Framebuilding Jig

By Jonathan Thompson

My first experiences of frame building involved some sort of jig. This was some angle iron bolted to a sheet of MDF (for my tandem BMX and recumbent) and then a proper jig at Downland Cycles for their framebuilding course. To start to make frames at home I thought I needed a jig. Looking at the retail options was a bit of a financial shock. Lovely though they were, they were all well into 4 figures which seemed a bit steep. How hard can it be?

Framebuilder Tooling – Using a Lathe

Framebuilder Tooling – Using a Lathe

By Jonathan Thompson

I have to confess to being a tool buyer. I’ve generally found the sooner you buy tooling the sooner it pays for itself and generally it always does.
For me the lathe was always a desire. When it came to building my jig it meant I could build a custom one rather than forking out on prebuilt one or someone else making the round bits. I also have a full time day job, so getting to machine shops during the week is never easy and I love the chance of learning some new skills. It also just opens up a whole lot of other jobs that are impossible without the right tools.

Internal Top Tube Cable Routing

Internal Top Tube Cable Routing

I have done this procedure several times on completed frames, but it is sensible to do it before the tube is brazed. Partly because it reduces the chances of frame distortion when you are brazing into tubes after assembly and partly because if it goes wrong it will be easy to re-do! I have only used brass tubes for this procedure, though it would be possible to use stainless tubes if you can obtain malleable enough ones of the correct diameter. Ceeway and various model making suppliers supply 7mm diameter brass tube with approximately 0.4mm walls. You need 500mm lengths to do the job. A 7mm tube will take a complete brake cable, holding it tightly. It would be possible to forgo the internal tube and simply run the cable in and out of the top tube but I suspect this may cause unacceptable noise from the cable being free inside the top tube, and allow water ingress.