its what the manual says
all the -2 etc are all different part numbers

no 20-8790 is the correct number no -2

if it says 2 its 2x qty

Hey Ara...
20-8790 is the Williams part number for a nyliner bearing used for 1/4 inch diameter shafts. (Bearing length .078 inch) That is what you need for A-16317.
Additionally, Williams used a suffix -1 through -9 for nyliner bearings with different lengths or for different shaft diameters. For example, 20-8790-1 is a nyliner bearing for a 3/16 inch shaft. 20-8790-2 is for a 5/16 inch shaft.
Wally

Incorrect. They are the same part but any suffix number refers to a non standard size/diameter for that part.

You got it.

Standard is 1/4 inch with no minus suffix number.
https://www.pinball.center/en/shop/pinball-parts/flipper-components/miscellaneous/7169/nyliner-1/4-20-8790

-2 on the end would be same part but a 5/16 inch.
https://www.pinball.center/en/shop/pinball-parts/flipper-components/miscellaneous/7170/nyliner-5/16-20-8790-2

piss off pinsanity I know more about Williams part numbers than a hair on your head

I gave the correct info, I was saying if it had a 2 in the column qty is 2 not -2

go back to the funeral business

There is no quantity column on the A-16317 ball trough assembly page in the manual so the information given is erroneous.

After 27 years of buying/importing and selling pinball machines in conjunction with my current employment in the State AG's Department which provides just the right lifestyle/remuneration balance between the two, at this stage I am quite content in my career.

At the very least it certainly provides the outside perspective that seems to be severely lacking in some sections of the Australian pinball community.