Archive for the ‘Brazing’ Category.
March 30, 2007, 2:49 pm
This will be the last rack posting for a little while, until it is actually complete.
(click for more photos)
I installed the other stay and a backstop last night, cleaned up the flux, and mounted the rack on my bike. I only used it for a short ride this morning but it seems to work very well. I was worried that my stays were too far forward and would cause problems with the front wheel hook on the bus rack, but it wasn’t an issue.
Remaining work:
- Install a light mount. I think I’m going to get a Lumotec Oval and mount it between the stay and the wheel. It looks like there is enough space.
- Wire routing for the light.
- Fender eyelets (so the fender mounts to the rack)
The bike handles nicely with the front bag. This isn’t a surprise since it is a lower trail bike (45mm trail). There is a small amount of shimmy when riding no hands, but this will probably go away if I drop the tire pressure a little. I normally ride these tires (28mm Avocet Duros) at 75psi but they are at 90psi right now.
March 29, 2007, 2:52 pm
My vacation put a little hold on my rack making, but this week I did get to spend a few hours in the workshop. The gallery is updated.
I’m pretty happy with the progress for a first rack. I wish I had spent more time when making the bends for the rack top, some of them aren’t perfect and it makes the whole thing slightly wonky. The top has a slight twist in it when viewed from the front, it doesn’t all lie in a nice plane. It’ll definately be functional but it might not be pretty.
I’m pretty happy with how the mount to the fork crown came out. It is tricky to get everything to fit when you use a sidepull brake (instead of cantilevers). I should have left my mock-up brake on for the photos.
The other challenging part has been coming up with fixtures for holding things in place while I braze them. I built the rack in this order:
- Make the top
- Make the fork crown mount
- Attach the fork crown mount to the top
- Make and attach the stays to the top
- Make and attach the backstop to the top
Attaching the fork crown mount to the rack top was tricky. I did it by mounting a wheel (no tire) into the fork and putting a long and skinny piece of wood onto the wheel (coming off at a tangent). The end of the wood had a groove which held the front of the rack at the centerline. I useda ziptie around a spoke and the fork blade to keep the whole thing in compression. The rear of the rack was held against the mitered fork crown mount using this compression.
How do others do it?
March 13, 2007, 4:50 am
I finally made the plunge and bought the equipment necessary to braze racks out of steel. I spent a lot of time asking Alistair, framebuilding members, and random people at NAHBS what I should buy and finally ended up getting a Victor Superrange II. The torch is a little bigger than ideal, but the price for the whole kit was a lot cheaper than putting together my own kit with good regulators and a smaller airplane torch. The included regulator was also compatible with propane (I’m using Oxygen/Propane instead of the more common Oxygen/Acetylene). I also bought a Ridgid 3/8″ tubing bender, stocked up on files, and ordered a bunch of tubing from Aircraft Spruce.
The first project is a handlebar bag rack for my Trek road bike. It has caliper brakes and I’m not crazy about the common designs for racks that would fit.
Tonight I got home and built the platform:
It’s not perfect, but it’ll be perfectly functional. I messed up when measuring the platform and was off by about 1/4″ where it the two ends of the outer tubing join each other. I brazed in a little filler piece of tubing to make it work. The joint isn’t perfectly smooth, but I think it’ll be okay after I sand it out. The perimeter of the rack is made out of 3/8″ tubing because that is what works with my bender, but I’m using lighter 5/16″ tubing elsewhere. Click the picture to see more photos.
I’m excited about building some more and finishing up this. I think my second project will be a good lowrider rack for my Bike Friday, the stock one is terrible.
Lessons learned so far:
- Measure carefully when making the perimeter for a platform
- The flux that Henry James sells is much nicer than what I picked up from the local welding store. I can’t wait for my HJ order to arrive.
- Measure more carefully when trying to make things look balanced. My middle-stay is slightly off center.