Could someone tell me what material helicopter gearboxes are made from?
A quick illustration from the caterpillar world might help.
A cat hydraulic ram rod will bounce a ball bearing of specified density with a ping back up to a specified height, or it fails quality acceptance.
A cat clone looks identical, all nice and shiny, but the ball won't bounce more than half the cat height and only makes a dull thud sound..
The cat rod last five times longer and only costs twice as much.
Each chromium plated rod may be very similar in appearance but the underlying steel is a different kettle of fish altogether, and like coca cola, you won't get the recipe out of them.
A cat final drive will operate dry on oil for a couple of hours if the operator is deaf, but is very heavy on the pocket to fix.