[Jim Williams]

Neven,

Thanks for the hints about the drill bits. I found that a size #16 drill bit shank is very close to 4.5 mm. As a matter of fact, looking up the decimal equivalent, it is 0.1770", or 4.496 mm.

I used a couple of these drill bits on either side of the intermediate gear, and measured 137.22 mm across them. It looks like this gear passes the test, as the wear limit is 136.5 for a "0" gear (135.55 for a "1"), with lower numbers indicating what would be more wear. So it would seem the backlash numbers are only installation numbers, and as such are useful only when installing a new gear. I guess I could go out on a limb here and say that backlash numbers don't appear to be of any use when checking the intermediate gear to see if it is OK to reuse in a rebuild situation. One needs to measure the intermediate gear using the method in the little spec book to get anything meaningful.