Handmade Bicycles: Frame Building Class

Last week, I took a bicycle frame building class from Tim Sanner of Sanner Cycles in Palo Alto, California. I had been considering taking a frame building class from United Bicycle Institute in Ashland, Oregon for some time now and when I saw this class being offered so close to home, I jumped on the opportunity.

Tim’s class was appealing to me because of price, location, and surprisingly the minimal and low-tech toolset.

Pricewise, the course comes in at about one-third of the cost of UBI’s frame building courses and being able to sleep in my own bed also helped with cost savings. The cost of the course and materials was not significantly more than the cost of one of Sanner Cycles’ basic frames, so I thought it was a fine deal. And the classes are a two-to-one student/teacher ratio, which makes it easy to ask lots of questions. The current price of the course can be found here. (Note: I took the 5-day basic course.)

For a hobbyist, it was nice to learn how to build a bicycle frame with a tool set that was affordable. I figured this would make it more likely that I would purchase some tools and continue to build frames. At some point I think it would also be beneficial to take a course from UBI and learn some advanced techniques and have access to a wider variety of tools, but to start, I think this course provides good instruction and enough hands-on experience to have a go at frame building as a hobby.

If you would like to see photos from the class, visit my Flickr page. And if you want to see some video footage my classmate Dan from Trek Travel took, check out this page. Otherwise, if you want to hear more about the class, read on!

Here’s a rough itinerary of the class and some of my thoughts:

Day 1: Design, Measure, and Cut

I wanted to build a bicycle frame for my girlfriend and use the components off of one of my older road bikes for the build. Based off of a few measurements: inseam, sternum height, and overall height; I designed a frame geometry that was suitable for her. I could have gotten much more complex with the frame design, but being my first one, I let Tim guide the process and use his frame building insight to decide upon a suitable geometry. One thing to note though is that it is good practice to have a fork and headset in mind when designing the frame.

Using a big piece of paper, compass, straight edge, metric ruler, and a pen; I got to work drawing the frame and taking measurements for which I would base my cuts.

Next we took our measurements, trimmed our tubes to the approximate lengths, and cut miters in our tubes using a hole saw and tube mitering tool. Ideally, the miters will be at a precise angle and diameter so that when the frame is dry fitted, the tubes will align flush with each other maximizing surface area for a solid joint. Unfortunately, my cuts were not nearly perfect. We used lugs which gives a bigger margin for error than a fillet brazed or welded bicycle frame, so my cuts ended up being fine.

Day 2: Introduction to Brazing, Lug Preparation

This was an exciting day. For the first time, we were going to braze something. We prepped our seat stays to accept the curvature of a larger diameter tube. This would eventually become the top of our seat stay. We learned how to handle the oxy-acetylene torch, the purpose of flux, and the properties of silver versus brass.

I admit, I thought brazing was going to be a breeze, but it was actually a bit trickier than I had expected. Having Tim looking over my shoulder definitely helped the quality of my joints. Ironically, because of this I have a feeling that my second and third bicycle frames will not look as nice as my first.

The rest of the day was devoted to grinding our seat stays to their final shape and grinding the inside of our lugs to prep them for brazing. In this class, we used power hand tools (drill, handheld disc grinder, rotary tool) to do most of our prep and finish work. At first it was a little intimidating to see metal sparks flying all over the place and all over me, but eventually I got the hang of it. Remember: Safety First. Protect those eyes and ears.

Day 3: Jig, Tack, and Braze

This day felt like huge progress was being made because for the first time we had something that resembled a bicycle frame. I admit that up until this point, I was a bit worried that my frame would be warped and crooked.

We spent some time prepping our tubes by sanding them down to remove any imperfections and impurities that would degrade the quality of the braze. Then we added flux, fit the tubes together, and put them into Tim’s Bringheli Jig. At this point, we fine tuned all the angles tacked some silver onto the frame to hold its shape…and voilà!

I felt a huge relief seeing the tubes in the shape of a bicycle frame. I was really worried that some of the mistakes I had made in the beginning would magnify, but was relieved to find that using lugs and a jig gave me comfortable wiggle room.

Day 4: Brazing and Aligning

We spent a good portion of day 4 brazing all the joints of our bicycle frame. Being in control of the silver or brass and dictating its flow and movement is truly an art. I was a bit awkward, used a little to much in some areas and a little to little in others. Tim was always helpful with pointers. And after taking my sweet time and revisiting some areas perhaps two or three times, I had some solid joints.

We worked in a particular order: braze bottom bracket, cut and face the bottom bracket, cold align seat tube and down tube on an alignment table, braze head tube, and braze seat cluster. This created a frame with very tight tolerances in the end. Tim showed us a couple production frames and the margin of error of a production frame versus a handmade one. I was really impressed with how straight our handmade frames were in comparison to the production ones.

Day 5: Brazing and Finishing Touches

On our final day, we basically finished our brazing, filled in some gaps we may have missed, cut and reamed our head tube and seat tube, and attached our braze-ons. At this point I was pretty comfortable with the torch and my eye for brazing temperatures had improved noticeably.

At the end of the day, we were left with a bicycle frame that was road ready, but far from pretty. Since we were short on time at the end of the week, I ended up taking the bicycle frame home to do the cleanup. This entailed soaking the frame in my bathtub to remove the excess flux, filing away the extra silver and brass, and sanding the finish.

All in all, the class was a success. A lot of the mystery of frame building has been lifted and I am really eager to buy some tools and make more frames.

I will be making a follow up trip to drop of the frame for a powder coat at Precision Powder Coating and will post some pictures of the final build when it’s ready.

Update (12/09/09): As of today, all of Tim’s classes are booked indefinitely. It looks like there’s been a lot of interest in taking a frame building class in the Bay Area, so I thought I would jot down some additional notes. I have not taken either of the two following classes, but they were classes I was considering at one point or another.

TechShop in Menlo Park offers a road bicycle frame building class. Although, at the moment, I do not see it in their course offerings. It might be worth giving them a call and telling them you’re interested. This class does have a prerequisite of two TIG welding classes if I remember correctly.

The Crucible in Oakland offers a single speed mountain bike frame building class. This class has a prerequisite of two TIG welding classes and a machine shop class.

Update (03/13/10): Here are some follow up posts.

Kate’s frame after coming back from the powder coater.
Kate’s bike all built up.
Some photos of the build on my Flickr page.

Update (10/05/10): Since this post is so dang popular, here is another follow up post with some good bicycle framebuilding resources. Resources for the Budding Framebuilder.

Update (08/01/11): I took the UBI framebuilding class. Post here.

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