By the time you machine all your parts at 20% reduced capacity (for those tools that need it) vs replacing an item that should be replaced every 5 years (spindle bearings) under normal wear conditions, you could have bought 10 sets of bearings. Not to mention, the machine wear and maintenance is deductible. I fail to see any logic in this argument, though it seems to be a popular one.
Machine bearing life due to 20% more rpm is negligible in the scheme of things. It costs MORE not to use the full capacity of the machine. The enemy of spindle bearings is vibration and chatter, not rpm.
The Manufacturing Reliquary
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