December 11, 2019 | Chris Blandford
Moving forward. Steps for today:
12. Check Frame Alignment
13. (Align Frame if Necessary)
I only recently purchased my little alignment table. Up until my last couple frames, I’d been relying on my fixtures and the various string/straightedge/frame-alignment-gauge methods to check alignment. The classroom at UBI housed a full-size BB-tower style alignment table; in both of my courses it served as a very heavy coffee table.
I think the attitude there is that if you use good fixturing and processes, an alignment table isn’t really necessary. I think I understand the wisdom in that. One of my favorite walk-around-town activities is one-eyed-squinting at the rear ends of production bikes that I see locked up to racks. Yikes. At least in terms of alignment, the bar isn’t set very high. And really, I don’t know enough about bikes to know whether any of it matters or not. Especially for the types of bikes that I build and ride.
So, I “align” my frames to a level that my perfectionism will accept. Which--given that I’m new to making bicycles--is a pretty loose tolerance. I’ve put a couple of my scrapped frames on my little table and felt the amount of force that it takes to move a head tube even a half-millimeter. A triangle made out of tubular steel is shockingly strong. In essence, I’ve quasi-decided that: A. if something needs mild correction, it isn’t worth me yanking the hell out of my frame to correct it; and B. if something needs major correction, I should probably just start over. So--as of right now--“aligning” my frames is really just a way to gain a little feedback as I go along. I'll nudge dropouts, but that's about it. I use the alignment process as a tool for improving the work on my next frame, not as a way to correct my current incompetencies. I hope that makes sense.
With that said, here’s what I check and how I check it. (Note: I didn’t take photos of this until after I’d finished the fillets, but I checked the frame before I started filing. Nevermind the shine for now!)