Cantilever Brake Mount Jig?

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Reed McFarland

Feb 20, 2024, 9:57:17 PMFeb 20
Hello Everyone,

Is anyone looking to sell a cantilever brake mount jig? I’m just a hobbyist, but I don’t think I’ve ever seen even a used one for sale. I have plenty of local framebuilders who have them, but I got into the game too late and now no one is even producing them. So it seems.

I’m aware I can make one on my own, but I’m interested in professionally made options before I spend the time attempting to make one.

Reed McFarland

Mark Bulgier

Feb 21, 2024, 10:02:35 PMFeb 21
to Reed McFarland,
Kids these days! 😉

In all my years of full-time framebuilding, I never had much of a canti boss tool, despite most of the frames I made having cantis. 
 I had a piece of steel with two 6 mm holes in it.  M6 screws though the piece of steel, threaded into the bosses.  Miter the bosses so they match up with the blades or stays at the desired boss width.  Measure the height (from the hub axle) with a tape measure.

Worthwhile addition:  add a second piece of steel, with just one hole, in the center, tapped 1/4" x 20 to take a piece all-thread with a wingnut brazed to the end.  It goes through the first piece I mentioned and into the second, pinches the stays or blades between the 2 pieces of steel.  Now the subassembly doesn't fall off if you bump it, hallelujah! And you can adjust the height of one without moving the other, and rotate it every which way for fluxing and brazing.

If this seems imprecise to you, all I can say is it was plenty precise enough, and that was back when cantis meant Mafac, with zero up-down adjustment range (other than the "nod" angle of the pad, but no up/down translation independent of the angle)  I figger my method was accurate to a mm, probably 0.5 mm with good lighting.

If you don't need your posts to be exactly 80 mm (or whatever) apart, i.e. if you're willing to compromise on that width to make your miters match up with the blades/stays, then slot one of the holes where the bosses screw on, to give you some width wiggle room.  Or just make another top plate — it's just a piece of steel from the scrap pile with 3 holes drilled in it, five minutes to make one if you're slow like me.

Or hold out for one that's all CNC milled, corner-rounded and orange anodized, with engraved filigree like a Clickspring masterpiece.  But the brakes won't feel any different out on the trail.

Mark B in Seattle

Jon Norstog

Feb 22, 2024, 12:03:06 AMFeb 22
to Mark Bulgier, Reed McFarland,
I made my own canti jig when I started building,  Two holes and a third to line up with the frame centerline.  All mu equipment I made myself, first four-five years.  When I moved the shop to Idaho I had an indoor workspace and I picked upa Henry James frame jig.  It came with the HJ canti jig.  Like all of Hank's stuff it was fiddly and required a bit of thinking to use, but could be quite accurate if you did your part.  It is what I use to this day.   I've seen brand name bikes with the bosses visibly out of line,  Mine have never given the client headaches.

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Steven Johnson

Feb 22, 2024, 5:43:18 AMFeb 22

About the only successful brazing I have ever done. Rear only.

Steven Johnson
Millersville, MD, USA

Adam Decroix

Feb 25, 2024, 8:46:06 PMFeb 25
to Framebuilders
Hi Reed,
I am about as far as one could get from being called a machinist, but recently I was left no option but to make a pair of jigs that are a crude copy of the Anvil/HJ fixtures for this purpose. I had some 1/2" aluminum plate cut on a water-jet that serves as the backbone for the jig. I used two Paragon Machine Works tube blocks, a dummy axle from Alex Meade since he uses a C-clip as a hard stop that centers nicely with the PMW tube block, and some misc. hardware from McMaster-Carr. All of the rest of the work was done on my mini mill & mini lathe with basic tooling and a bit of patience. It was pretty rewarding and I learned a ton in the process! All told, I probably spent around $100 for each one. If you are interested in copying this I still have a spare plate that I'd be happy to sell!
Adam de Croix

Adam Decroix

Feb 26, 2024, 12:02:08 AMFeb 26
to Framebuilders
I forgot a picture!
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