Dave Arbogast wrote:

When I did die design, we would solve this problem with an interference fit of
several thousands of an inch. You'd have a small radius on the outside of the
shaft. You'd freeze the shaft with a CO2 extinguisher, bake the gear to 500 F in
an oven (not hot enough to distort it) and press them together. You
need to do the calculations on how much the IO & OD change with the temp delta...

Once together, it may as well be a weld, w/o the stress & metal crystal changes.

It's my understanding that the same technique is commonly used by mints (the folks that
make coinage) to make certain bimetallic coins.  For example, the Portuguese Escudo is a
two-part coin: an outer silver-colored "donut" and an inner gold-colored disk.  My
Portuguese friends that the inner disk cannot be pressed out.

Russell Kent

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