Kevin Yoshihara Spartan Superway: Week 11: Somewhat Positive Results, Work Still Needed

Utilization of the wheel on the bender arm worked as planned, producing the curve that was shown in last week's post. Upon using the wheel to bend a second piece of test material this last weekend, the bender failed to produce the same result. Investigation revealed that the 5/16" bolt used to hold the wheel in place was not strong enough, and had deformed due to the shear stress applied. A 3/8" bolt was subsequently tested, and subsequently failed as well. A simple design using 3/4" aluminum bar stock instead of a bolt, and 2" aluminum bar stock instead of a wheel fared better, resisting the shear force applied. Interestingly enough, the plywood die did not appear to deform in shape in spite of the loads applied.

Free, sturdy table legs were acquired over the weekend, and plans have been made to create a table for the bender for the Spartan Superway workshop. The table will be made '2x4's and aluminum diamond plate or plywood (all of which was free), along with some bolts purchased from the local hardware store (Lowes).

As a side note, the bill of materials for the project was due on November 15th. The many materials used in the build thus far have been free or have been scrap left over from previous years. Owning the many tools used and doing the work myself, labor and tooling costs are zero. As things currently stand, the cost for our material bender may be no more than the nuts, bolts, and washers that are used to hold everything together. This would be a large win for the Superway project, without even needing to calculate what would have been the comparative cost had the work been done externally.