I realize this is an old thread but I'm adding my recent experience so that it may help the next guy with this machine in need of feed screw nuts.
I also have a Supermax YCM-16VS, 1986 vintage, that was in need of feed screw nuts. High Quality Tools, Eastlake OH stocks Bridgeport parts and was willing to work with me to find replacement nuts and are only 45 minutes away. We tried the Bridgeport inch (1069-2 and 1070-2) feed nuts and the metric feed nuts but neither fit my feed screw. Looking at the Bridgeport nuts, it looked like I had the metric thread form but with inch thread pitch so neither was close to fitting, though the metric nut did go on farther, about two to three turns before locking up. I'm guessing that's the difference between the 5mm (0.197") pitch of the nut vs 0.200" (5 TPI) pitch of the screw but there was no way to be sure. However, they did have an old dogbone assembly from a house (HQT) brand import mill tucked away on a shelf and my feed screws DID fit those nuts. The tag on the dogbone says "For HQT VS or V5 R8). Since the nuts had almost no wear and the same OD as my old nuts, I bought the assembly and modified the nuts to fit the YCM dogbone so I now have almost zero wear feed nuts for a little under $200 and a couple hours splitting them and, after knocking off the dings and high spots, they now fit very nicely.
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