Chapter 2: Tube mitering and bulding a rig.

I recently purchased a set of Columbus Zona high strength steel bike tubing from Hillbrinck up in NSW, and after setting my mind on the design, the next step was of course mitering all the tubes so they would match each other nicely. Since I don´t have a set of crown saws I have been using the freeware Tube miter which is simple as, but most useful! I recommend to check it out if you are into this stuff. This software allows you to enter the diameter of the tube to miter and the angle to meet, and it creates a stencil that you can position on the tube. Then is up to your grainding skills to get it right.

In order to get a good guide of where each tube should be sitting with respect to one another I printed a 1:1 print of the dessign and I put it on top of a sturdy wooden board.

As locking points I used an old bottom bracket to fix the BB tube to the board. To fix chainstays and seatstays I used an old and rusty rear hub which will give me the perfect separation between dropouts plus sets up the right distance for the stays.

Each tube is secured to the board by 2 allen screws which push from behind the board and a metal zip tie (plastic ones will melt when it comes to welding!). This way we have two points to regulate the heigh of each tube.

One 0f the most complicated steps is to position the right chainstay and seat stay since they extend underneath the guide board, therefore a hole had to be cut into the wood to allow the stays to go through, this however makes it easier to be secured onto the rig and therefore allows for a more stable joint that won´t move when it comes to welding.

Next step will be to position and secure the right seatstay.

Keep and eye on ferropur bikes!