Fork build questions
So I've been daydreaming about building a fork for a while. I've got a fork crown from an old Bontrager mtb fork. Maybe its a Tange Switchblade fork crown, I'm not sure. They're both essentially the same thing. They were straight blade, tapered and very elegant. I would like to build a semi-replica of these super cool forks but with a twist. I'd like to build it to accomodate touring needs. In other words, I want dual eyelets, cantilever mounts, and mid-fork lowrider mounts.
Anyway - Been looking at stuff at Nova Cycle Supply and am a little confused.
My crown measures 1" (25.4mm) with a dial caliper where the round tubes bolt into it. The only round, straight fork blades are called out as 24 mm x .9mm x 390mm long. The smaller end measures 12.5 mm with 1.8 mm wall. 290mm long taper: http://www.cycle-frames.com/bicycle-...ACK-ROUND.html
The dropouts I'm considering are these: http://www.cycle-frames.com/bicycle-...-W-2-EYES.html
12 mm plug, 14 mm lip.
My questions are these:
Is the fork tubing measured on the ID and wall thickness or OD and wall?
If it is called out based on ID, then I may be in luck. The dropouts with their 12 mm plug will fit right into the end of the fork. The large end at 24mm ID (presumably) and .9 mm wall gives an OD of 25.8mm. Of course they would have to be cut to length (fitting to a 1985 Peugeot Canyon Express MTB) and kitted out with canti bosses and the lowrider mounts, but overall this should be a really simple build if the fork blade dimensions are measured on the ID of the tube.
The dropouts plugs will have .5 mm clearance for braze material to wick into. Is this an acceptable joint thickness for safety's sake?
Lastly, will these be durable enough to be used in a touring type application? I don't know when I'll ever actually take a tour, but the bike is in the process of being converted over with that end in mind.
I have a highly accomplished welder here and I have utmost confidence in his abilities to do a good job.
I've never done this kind of work before so if I'm waaayy off base let me know.
One other thing: Where the fork bolts into the crown is the thinnest of the material. I'm a little leery of this so was planning on brazing in some reinforcement to the ID that would extend maybe 1-1/2" to 2" into the ID. Is this a good or a bad idea. I can spin something up in a lathe to be a very close tolerance fit......
Last edited by Smokinapankake; 02-02-12 at 04:47 PM.
Reason: Added info