S-T Morrissey wrote: > Regarding shim stock for hinges or flexures: > > In the event that C&H sells out of the shim stock that Jim has > posted info on, it can be obtained from McMaster Carr Supply > (630 833 0300): (MC, VISA, by UPS) Recently, I have located sources for thin beryllium copper which I consider the ideal material for hinges. The sample which I have is .002 thick, and has a strength of 70,000 psi. By heat treating at 600 deg. F for a couple hours, the strength is 150,000 psi. Due to the fact that the modulus of elasticity is about 60 % of steel, the hinges are more flexible. It is also fully solderable after removal of the thin oxide. By having a simple fixture, the part can be formed in the soft condition, and it will retain any shape after hardening. As an example, the parts which are 1/4 inch wide by .002 thick have an "S" shape to fit around a 1/2 in. rod and have an elastic limit of 75 pounds each. In order to heat treat it, I have constructed a tiny oven of firebrick which is placed on a gas range with a thermocouple sensor. I would consder making hinge springs for others at minimal cost if we can agree on a configuration which would be generally useful. The present springs are designed to fit around two 1/2 inch cylinders placed .7 inches apart, and be fastened by 4-40 screws on the far sides of the cylinders. The mounting holes are 1.67 inches apart, so that a pair cross at 90 degrees when mounted in opposite directions. Tabs of approximately 3/8 inch on each end can be used to conduct currents of any reasonable magnitude. George Harris - Benicia, CA __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>