Bamboo Bike Frame.

Step 4 Mitering

This was easily the most labor-intensive part of building the bike. I had decided that using the joints from old bike frames was cheating, so I had to miter each joint by hand instead of just cutting the bamboo and fitting it on.

The seat tube is mitered to the seat tube at 90 degrees. Print out a template from tubemiter.exe, cut it out, tape it onto the tube, and go to town! First, I Sharpied in the line so that I could see the edge better. Then, I cut longitudinal slots down to the line, so that the bamboo would chip off as I sawed along the line. Then, I sawed along the line, and I finished with rasp work. After testing it against the actual piece I was mitering to, I did some more rasp work. And then tested again, and then some more rasp work. And so on, until I achieved a good fit. It doesn't have to be super tight, since you are tacking the two together with epoxy and not welding it, but it can't be *too* bad of a fit.

For the down tube and the top tube you will have to miter both ends, and they both have to be straight. The down tube will also have to be mitered to two tubes. My best advice is to be patient and careful. Use your protractor to check if your angles are the same in real life and in your design.

For the seat stays I used this calculator instead to make templates for the offset miters.

The bridges are very small, so they are hard to miter. I included pictures of how I did it.

Comments

[thavinator]

Your "miters" are called notches or fishmouths, and the jig that would have made them much more easily is appropriately called a pipe notcher Beware the cheap ones if you plan to do any actual metal fabrication with them, and if you're not keen to spend the money on one yourself, look for someone who does roll cages or general fabrication, they should have one.

[xman]

Thanks, that's going into the instructable for sure! I knew there must be a better way to do it...