331 oversize bearings diameters ?

[Philippe M. Ruel]

I came across an old (1960s or before) reference table for Federal Mogul bearings.

It shows  correspondance between Federal Mogul part #1560SA and Cadillac part #3630224 for 1949-1954 331 rod bearings.

As you can see, they were available in several sizes. I guess 10-20-30-60 mean .010 to .060" oversize bearings.
What is the use of "1" and "2", which would be .001 and .002 oversize ?
Do/did machinists commonly regrind crankshaft journals to these tiny values ?

Or were crankshafts sorted at factory, depending on quality controls ? This was/is a common practice of other car makers for parts like pistons, but it sounds strange that Cadillac did that at that time.

I haven't found a mention of oversize bearing sizes, neither in my '52 shop manual nor in my parts list.

[Dave Shepherd]

Because of machining tolerances back then some cranks may have been undersized by 001 or 002, 010 and more under were for reconditioning purposes as a rule.  No .001 or .002 cranks get refinished to that size, 10 under would be the minimum clean up, usually more like 20 or 30.