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Old 11-03-2014, 05:52 PM   #24
Delfin
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Join Date: Jan 2010
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Quote:
Originally Posted by manyboats View Post
When a new propeller shaft is made how close to the size in question should it be? There must be a tolerance of how much less than the specified size it can be. I'm sure the stern (cutlass) bearing only comes in one size and the shaft is supposed to be fit to the stern bearing. One wouldn't want it tight of course as it would probably heat up and self destruct. One wouldn't want it loose enough to "rattle" around in the bearing causing excessive wear and noise.

Should a "clunking sound" be heard if one tried to move the shaft back and forth? I do hear a clunking sound and I think it's not right but how do I know how loose or tight the stern bearing to shaft fit should be? My shaft is 1.25" dia. How many thousands of an inch tolerance should be maximum? As the prop shaft becomes smaller how small is too small? I had a new prop shaft made and I think it's smaller than my 10 year oil shaft. I want to call the yard boys on this or be assured "that's normal". And I don't want to cause the yard any unnecessary trouble and expense. But I definitely want the stern bearing to fit the shaft properly.
Eric, I just went through this with my cutlass bearings. Your size shaft should have clearance of between .003" and .008", which is something you should be able to measure yourself. If it is greater than that, the cutlass bearing needs to be replaced, or the shaft is out of spec.
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