Hi, I've some trouble adjusting the clearance of the headstock bearings on my lathe. It's a WBL210 Weiss lathe ; max Dia 200mm, 300mm between centers, roughly a 8x12" lathe of the same design as the 7x12 ones.

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The surface finish was not as smooth as expected: even with shallow pass with slow motion. It was looking like a ~2mm pitch thread with a very low roughness pretty lower than 0.1mm.
Probably the leadscrew pitch amplified by the gear train and some play in between the spindle bearings.
Tightening the nut at the end of the arbor improved the situation but I couldn't manage to tighten it farther. The bearings seemed to be blocked by something. The drawing doesn't show any obstacle however. the bearings are 30206, tapered roller type.

On to the other hand, 6 months ago I attempted to troubleshoot the spindle of my milling machine (model? VM18L from the same manufacturer), ending by tuning the deep groove bearing clearances. It went the same way as the lathe. But since I didn't notice any discrepancy, I let it as it was and remounted the spindle.

Several times, I've replaced tapered bearings on the wheel hubs of my cars without any extracting issues. They went well adjusted but not needing any great force to get them.
I assume that the accuracy of a machine spindle being greater than a car's hub one, leads to a tighter adjustment. But, does it really need an extractor or is that a specificity of this manufacturer or even a bad quality level ?