I was recently faced with a broken on-off toggle switch on my Ampico A.
I found a flat-handled SPST toggle switch at Radio Shack which worked
very well as a replacement.  Their part number is Model 275-651,
Catalog # 2750651, "flat lever heavy-duty toggle switch".

I had to shorten the overall length of the toggle handle by about 1/2"
and then I carefully bored a 1/8" ID hole at a right angle through the
toggle handle, removed the original 1/8" brass actuating rod from the
original switch, then inserted that into the newly-bored hole in the
toggle handle.

I used "Bondic" to bond the brass rod to the toggle handle.  Bondic is
a liquid plastic welding agent which permanently sets in four seconds
with the application of ultraviolet light.  I replaced this new switch
assembly back into the cast metal switch housing, reassembled
everything and it is working like a charm.

The toggle spring action/strength of this Radio Shack switch was more
consistent with the original Hubbell switch on the Ampico.  Most of
the now-available cylindrical-handle toggle switches have a very strong
toggle spring action and will not work well with the brass actuating
rod (engaging with the "off" function pneumatic) as the toggle handle
itself has a tendency to "roll" in the toggle switch assembly and the
actuating rod will not stay at a right angle to the horizontal action
of the toggle switch.

Terry Hochmuth