Wear - Shaft

Leviathon
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Wear - Shaft

Postby Leviathon » Sun Apr 22, 2018 11:33 am

So replacing cutlass bearings, what is normal for wear on the prop shaft where it rides on the bearing? Is there a tolerance rating? Trying not to break out another thou.
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan

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Busia
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Re: Wear - Shaft

Postby Busia » Sun Apr 22, 2018 12:11 pm

Normal would be zero wear. You have a stainless shaft in a rubber bushing, lubricated with water. Normally the rubber cutless will wear and be replaced. How much wear is allowed is affected by how big is the shaft, how well it is aligned, how much vibration you have, how much torque you are putting on it, cost to change it, how critical is it. I would at least make sure the shaft is smooth with no nicks or sharp edges. A real machine shop can make new shafts easily, they are not complicated.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

jralbert
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Re: Wear - Shaft

Postby jralbert » Sun Apr 22, 2018 12:42 pm

Advice from a boat maintenance article I read: double the wear you measure on one side of the shaft. If, for example, there's a 1/8" notch, it's actually 1/4" because the wear, of course, is on both sides of the shaft. This example is extreme - 1/4" is a failure waiting to happen. Hope yours is just an insignificant scratch at worst.

Best, as Busia points out above, is no wear.

Google turns up many discussions on shaft wear, some seem to be more informed than others.
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

Leviathon
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Re: Wear - Shaft

Postby Leviathon » Sun Apr 22, 2018 1:38 pm

Unfortunately I think most of these 45+ year old boats have not been routinely maintained, so 45 years worth of use, probably better replace it. Will just have the shop that is making the struts and rudders throw a couple shafts on the bill.
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan

TinLizzy
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Location: Lake Superior-Michigan's U.P.

Re: Wear - Shaft

Postby TinLizzy » Sun Apr 22, 2018 3:58 pm

They can use the old shafts for the rudders if they are 1".
Rodney
1975 28 Express-Twin 350 Chevy's, Raw Water cooled
Portage Canal Waterway-Upper Peninsula,Lake Superior

EWRice
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Re: Wear - Shaft

Postby EWRice » Mon Apr 23, 2018 9:06 am

You are going to have some wear and that is normal. A normal wear is a very shinny area with smooth transition into the shaft area outside the bearing. You may feel some smooth grooves in the shaft, but as long as you can't hook your fingernail in them you are generally ok. The most accurate and unscientific way to check is to slide a new cutless bearing on. If there is little to no play you are good to go.

I second using the old shafts for a new rudder shaft.
Muskegon Lake
1972 32' Express flybridge
"AL13"
Twin 318s
On board air & prime 920
1963 Thompson Super Sea Lancer
Graymarine 327
1961 Alumacraft 12'
'55 10hp Johnson

Leviathon
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Re: Wear - Shaft

Postby Leviathon » Mon Apr 23, 2018 4:34 pm

Now that the rudders are done - Yes - that is an obvious and excellent suggestion. That did not cross my mind!! Bottom line is, I was going to have to have some work done to the shafts as the crusaders with reduction gear add about 6 inches to the drive train. I would have had to cut them down anyway. Will see as soon as I get engines in how long of a prop shaft is required and just have them cut to size. Thanks All!
Steve and Mary Levi
1973 32' Marinette Fisherman
Twin Chrysler 360's
El Ohssa
St. Joseph, Michigan


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