We see a lot of beautiful bicycles on The Spoken, most of them made by hand by small business owners, entrepreneurs and enthusiasts. All of them, however, have been created by people with an immense passion for their craft and for the quality of riding their bikes afford. We all appreciate a fine, hand made bicycle, but unless you’ve actually picked up a torch, donned the glasses and brazed one tube to another, frame building can be seen as a bit of a dark art.
Dan Bailey is one of those craftsmen, building frames in his own shop by the name of Pallas Athena Custom Bicycles, in Minneapolis, and over the next few weeks he’s going to take us through the process involved with building a cyclocross frame from Columbus Zona and Life tubes. Here’s Step 1.
Blueprint and Tubes: This is where it all starts. A blueprint (thanks, BikeCAD!) and a pile of tubes (maybe a cold beer). This is the calm before the storm. Tubes are marked and have annotations on them about cut diameters, angles, and other information I need to get the tubes ready for conversion into a frame. This frame is for a local racer who’s pretty strong and likes a stiff frame. Given the nature of a lot of American cyclocross courses, we’ve decided to make it a little more agile by giving it a slightly steeper head tube angle and have decreased the amount of bottom bracket drop just a bit.
Top Tube Mitering: Just a quick shot of the hole saw cutting into the back end of the top tube where it’ll meet the seat tube. Not the most critical joint on the frame, but they’re all important. After the miter, it’ll be test-fit against the seat tube and fine-tuned with hand files if needed. A tight fitting miter is incredibly important, as capillary action will draw liquid bronze to the inside of the joint and create a small internal fillet.
Down Tube Miter Prep: Getting miters in-phase with each other can be tricky business. When I did all my miters by hand (pre-mill), I would scribe a center line down the tube and apply mitering templates before cutting everything by hand. Now, with a mill, I can use tubing blocks and a flat reference plate to ensure that the miters are completely in-phase with each other. Like all other miters, this will be test-fit and fine-tuned by hand.
Workshop Temp: It’s warming up! To some of you 46 Fahrenheit might seem a bit cold, but compared to two months ago, it’s positively tropical. At 46F, if I have a sweatshirt and work gloves, I can usually go for about 6 hours before I need to head into the house and warm up a bit. A big project for this summer will be finishing the insulation of the garage and adding a natural gas powered heater (200,000 BTUs of waaaaaaarm).
Next steps: Drilling out the head tube and bottom bracket shells, and getting the front triangle into the fixture for tacking, tinning, and building the fillets. Stay tuned!
