Continued from previous entry to work around the Kitlog Pro 2048 character limit.
5. The Harbor Freight 40" brake has a very sharp edge mandrel that will not produce the required 1/8" inside radius bends, so
- Adjusted the brake pressing plate back3-mm from the edge of the bending plate.
- Placed 1st 36-mm wide x 40" long strip of 0.025" 6061 into the brake12-mm.
- Bend as far as possible. See Fig. 1 & 2.
- Place the 2nd strip into the brake, under the 1st strip so that the 1st strip serves as a mandrel.
- Bend as far as possible.
- Then bend the actual parts using the 2nd strip as a mandrel. The radius of the resulting bends was close to the desired 1/8", but may have been slightly less.
- I should have explored increasing the distance from the brake pressing plate to the bending plate to 4 or 5-mm to increase the bend radius.
- I bought the parts (except for the piano hinge) to make a 54" Dave's Brake, but have not built it yet. If I do much more scratch building, I need to finish that brake!
5. Bend the other 3 36-mm strips to make L-angles. By trial and error, I conclude that inserting the strip17-mm past the bent edge of the mandrel resulted in ~equal width flanges on the L-angle.
6. Deburr the L-angles on the ScotchBrite wheel.
7. Cut 233-mm stiffeners from the new L-angle with snips and deburr with the ScotchBrite wheel. See Fig. 1. The part in the foreground is one of the original 186-mm stiffeners with both flanges cutoff at 30°. See Fig. 3.
