Hi,  About adding stiffeners to the pump of that Coinola machine,
if the machine didn't have stiffeners when it was built, you should not
add stiffeners when you restore it.  In fact, you should not _have to_
add stiffeners to make it work properly.

With very rare exceptions, these machines were built correctly when
they were made and sold originally.  If you think you can engineer it
better than the men who made them by the hundreds over decades, you've
got another think coming.

Yes, I know, manufacturers cut corners to save money, and some of
their ideas for avoiding patent problems didn't work out so well, but
something as fundamental as stiffeners in an air pump isn't going to
slip through the cracks.  So look carefully at the pump and see if it
has been tampered with.  If it appears to be original, you'd be well
advised to stop trying to 'improve' on the design.

Regards,
Craig Smith
Upstate New York