First off, this article series
(Book?) is about hobby building. It’s intended to share what I learned over a number of years of hobby frame building and some commercial framebuilding (that was really just hobby building with much higher costs.)
No one believes that their first frame will be trash. I didn’t when I built my first frame. Embrace the fact that your first frame will be trash. Give that trash a hug! Buy extra tubes ( or better yet, but straight gauge tubes). Copy an existing design.
Why copy an existing design?
If you’re enough of a bike nerd to want to build your own frame, you probably have an older steel bike that you like and are familiar with. Copy this frame. Copy this frame because you already know you like it. Frame design and geometry is a guessing game until you’ve made a number of frames in your size and then ridden them. You might also have a complete set of components for that old steel frame. If you copy it, you can move all of the components over to your new handbuilt frame and ride it. Chances are that you’ll love your new frame just because you made it, even though it’s a piece of crap. Embrace this bias and ride the wheels off of your new shitbox. Then break it down, build the original older steel frame back up, and realize that your first frame was inferior to the old production donor frame in every way.
Why a steel frame?
Steel is the easiest bike frame material. It’s light, strong, easily weldable, easy to braze, has a long fatigue life, and it’s inexpensive. If steel was invented tomorrow, the inventor would get a Nobel prize the next day.
But what about [some other material]?
New high end bike frames are made of carbon fiber. If you’re insistent that only carbon fiber will do, you should go to Dave Bohm’s school in Tucson. (Hat tip to Dave Bohm for getting framebuildingschool.com )
Aluminum frames require welding, and post weld heat treatment. Also, welding aluminum is less forgiving than steel because of aluminum’s reactivity with oxygen and other contaminants, not to mention that you have to go a lot faster. It’s doable, but is a level 2 ( maybe 5?) skill. Heat treatment for 6000 series aluminum requires high temperatures that you can’t do at home and 7000 series can be hard to source for the little bits unless you also have a machine shop to make aluminum in any shape you want.
Titanium frames require professional quality welding and fastidious cleanliness. Titanium is also a much more expensive material. I’ve never built a titanium frame because I never had the money to buy the tubes and a TIG welder at the same time.
What kind of frame?
Your first frame should be as simple as possible. A track frame is ideal, even if track bikes are a little silly. A road frame also makes sense. A rigid mountain bike frame is also good. Single speed bikes are a great choice. Also, Single speed bikes are rad. You should make one so you own one and ride one.