Welcome to the second installment in Paul Brodie’s frame-building dissertation, where he recreates a Whippet full-suspension bicycle frame from 1888, which will be presented at the 2012 North American Handmade Bicycle Show.
“I call this part of the Whippet the ‘Front Linkage’. The pivot is wide because it has to keep the seat tube from rubbing the inside of the rear stays. I can’t really call them seatstays, because they don’t attach to the seat tube. The Front Linkage was a bit of a challenge, and I enjoyed making it.
I machined a short tube in the lathe, and then filed a curved outer surface so it looks like a casting”.
“Here I’ve setup a little bending fixture in my vise. The rod is 4140 machined at a 2 degree taper, heated red hot, and bent to a right angle”:
“Because I tapered it from big to small, the end of the now bent and tapered rod is still perfectly faced, and sits perfectly on the tube’s spot faces for TIG welding”.
“After TIG welding, it reminds me of cattle for some reason…”:
“Here it sits over the frame tube, positioned for TIG tacking, using spacers and masking tape”.
“Right after fillet brazing, still quite hot”:
“After cooling slowly, the flux is soaked off with hot water”:
“A little bit of polishing… no problem”:
