I’m not sure what you are referring to here, what has a 2.43” bore?A standard 2.75" bearing will not fit in the 2.430" bore
You got it before I edited it. Fast. Its a 2.743 bore. The single race in the chuck is cracked and the balls and cage are worn out.With that type of bearing, the bore is usually a bit larger than nominal and the OD smaller, so that could be a 1-7/8 x 2-3/4. If you have a bearing distributor nearby, they would be able to cross reference it. McMaster unfortunately only goes up to a 1.5” bore. Is one of the chuck parts hardened that it runs on with only one race?
I’m not sure what you are referring to here, what has a 2.43” bore?
what's the metric size?Its an odd size. 2.735" OD with 1.900" ID and a single race . A standard 2.75" bearing will not fit in the 2.743" bore