Shaft Etching - Repair or Replace

[Finner]

When replacing cutlass bearing, Cleaning up the shaft is a good idea, how much etching can you remove / polish out on a 1 1/4" stainless shaft before it is logical to through it out and replace it? The Shaft is being spun By 85 HP diesel running at low power setting max 100 hours a year. Is there reasonable norms set. Any body have reference pictures?

[scubasteve]

I assume the etching is on the shaft where it makes contact with the cutlass bearing?

If you have concerns, take it to a prop shop that works on inboard running gear. They can evaluate the issue; check straightness and smooth out the etched area for much less than replacing the whole shaft.

[Finner]

That is correct and it sounds like the rigth advice.

[GordMay]

I wouldn’t bother with trying to polish/buff a shaft that isn’t exhibiting undesirable symptoms (ie: leaking at gland), for mere aesthetic reasons.

Minor shaft scratches can be DIY hand polished, but deeper scoring or etching may require more sophisticated procedures (electropolishing).

Carefully* polish the shaft using “fine” wet/dry (300-500 grit silicon carbide) sandpaper or emery cloth working "radially" around the shaft. Afterward, wash the shaft thoroughly with fresh water to remove any residual traces of abrasive, and apply a light coat of grease to ease reassembly.

* Any mechanically produced surface (ground, polished, buffed, lapped, honed, etc.) produces a work hardened, disturbed and damaged grain layer approximately 0.001" thick.