Steel/bronze bearing

What sort of surfaces are best for steel/bronze bearings?
I thought to polish the steel shaft as high as I can (shiny!), but leave
the bronze bearings as-bored, ie a little groovy. The bearings compress, so after wearing in I can adjust them back.
They are 22 mm and 18 mm dia, will run at up to maybe 10,000 rpm, lubricated, sideways loads only (it's the mill main shaft, with an integral ER20 chuck on the end, for a BCA).
Is this a good idea? Any ideas what kind of lubrication to use? Any suggestions? Looking for better-than-a-tenth (~1.5 microns) tir.
Ta,
-- Peter Fairbrother
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In an engine you'd have a number of similar situations.
1) The crankshaft pins and bearings would be pressure fed with oil and surface finish on both would be as fine as possible. Lubrication would be entirely by hydrodynamic wedge separating the running surfaces.
2) In the little end of a fully floating conrod the only lubrication would be from whatever got splashed up there. The pin would have an ultra fine finish and the bearing would be either honed to a cross hatch finish or roller burnished.
3) The finish in the gudgeon pin bore of a splash lubricated aluminium piston is normally roller burnished. I've also seen honed finishes but only in aftermarket pistons where perhaps the manufacturer didn't have the ideal equipment.
In other words lubrication, or the absence of large amounts of it, doesn't seem to impose a requirement for the bearing to have an oil retaining surface if that's what you're concerned about and I'd recommend a fine honed finish. I suggest that leaving it as bored wouldn't be ideal and the bearing contact area would be much reduced. The shaft would always be fine polished.
--
Dave Baker
Puma Race Engines
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Dave Baker wrote:

Thanks.
You mention roller burnishing - any idea of how strong the spring has to be?
Of course that1s a bit like asking how long is a piece of string, so suppose an 18 mm dia roller with a 3mm radius on the edge working on something like en24T - any idea?
Even a ball-park figure would help.
-- Peter Fairbrother
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None at all I'm afraid. It's not something I've ever looked into.
--
Dave Baker
Puma Race Engines
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