Final Braze-ons to Complete the Frame.

With the rear triangle assembled and the frame perfectly aligned using a dished wheel and a frame alignment gauge, we were ready to braze on the final little bits and doo-dads, like water bottle bosses, rack bosses, cable guides, etc.

One of the misleading things I've done on this blog is compress the timeline of frame building. I spent 3 weeks in Niles, MI building my frame, usually working between 9 and 12 hour days. We took the weekends off, but other than that I was in the shop filing, prepping, aligning, and worrying that I wouldn't finish in time. My second year of grad school started almost as soon as I got home.

Doug had a big box of brake bridges to choose from, but I picked this style because it fit perfectly in between my seat stays without filing. Doug said it was unfortunate I didn't get the experience of modifying a brake bridge and aligning it, something that takes most students all day to finish. 

My classmate was not as lucky as me, so here's his brake bridge, which he had to file down so that the brake hole was right in between those two marks. In case you're curious, the best way to find out where to put the brake bridge is to add the reach of your brake calipers to the radius of your wheel, then measure from the dropout center up the seat stay and make your mark. 

This contraption holds the derailleur cable braze-on to the frame while brazing. 

The brake cable stop boss is supposed to be 90mm from the middle of the nearest lug. 

Doug is using a straight edge to position the cable stop. This is also how you find the center-line of a tube: put that straight edge on then measure 1/2"away from it, and that's the middle of a 1" tube. 

This dohicky from Sputik Supply held the cable stop in place while brazing. 

The derailleur cable stop boss is supposed to be about 6mm away from the center line. 

Here we're just setting up the caliper.

See? Exactly 12mm apart. We used a half slip-tube to make sure the braze-ons were level with each other. Sadly, one of the stop bosses shifted while brazing and now is pointed a little cock-eyed. Whoops, that's the quirk of a handbuilt frame!

The water bottle bosses are to be placed 175mm away from the BB. I drilled them into the down tube with a 1/32 bit and worked my way up to a bigger bit. Drilling into a round tube is tricky. I used a center punch to guide me, and files helped correct minor variations. Brazing the bosses into the tube was surprisingly easy, though. 

Here's the finished frame, cooling, ready to be sandblasted. 

I just want to show off this seat post lug because I spent so many, many hours making it perfect. 

This is a slip tube that I added to the lug and head tube to give me some extra stack height. I used my files to make it match the leg before painting. Oh so many hours of filing! Round things are especially hard to file, luckily by this point I had a lot of practice. 

Here's Doug preparing to drill some holes for the rack bosses in the seat stay. 

Here's my custom lug. It's shiny because after I brazed it all together I spent a few dozen hours thinning it and evening it out with my Swiss file.

Boy and his dog.