bikes

I reached a milestone today on bike manufacturing. My friends were able to help me make a special chuck that can adapt the carbide hole saws I bought from amazon to the spindle of a mill machine. Here is a video of a test miter on some scrap tube.



This is a google drive link so you may need to copy the link into a new browser window to get the video to play.

This is the setup I will likely be using to miter real tube for the bike frame. The tube is held at the correct angle using a 3d printed tube holder, while some steel tube blocks allow the vice jaws on the mil table to grip the tube without crushing it.



My prior miters were done a lathe, a mil has the advantage though that it is easier to align the centers of the tube and hole saw. Compound miters such as seen on the down tube of most bikes are also easier to do on the mill since the four sides nature of the tube holder blocks allows the tube to be rotated exactly 90 degrees without meticulous measurement.

It is taking some time, but I am also making some progress on learning how to ride a unicycle. Today I was able to successfully complete a turn around pillar, which I was very pleased with.



Again this is a google drive link so it will need to be opened in a new tab to play.

If anyone here is still into bamboo/wooden bikes, this is a bike that was recently donated to a bike store near where I live. It turns out that the wooden tubes are affixed to metal lugs, which helps hold the bike together. The bike is not purely wooden.

If anyone here wants to learn more about the mathmatics behind bike handling, this forum discussion here contains a lot of useful information.

https://www.bentrideronline.com/messageboard/forum/main-category/specialty-discussions/technical-discussion/3024052-mathmatical-modelling-of-bikes-and-trikes/page2

I began mitering the tube for my first frame today, this is the miter for the downtube and bottom bracket shell.

I was able to make one more cut on the tube. The down tube now fits well with the head tube of the bike as well as the bottom bracket. If all goes well, I should have some time this weekend to finish mitering the rest of the tubes.