Worn prop shaft

[Poignard]

A 1" nominal diameter propshaft, worn .007" undersize at the cutless and inboard bearing locations.
Should it be renewed?

 

[PCUK]

No

 

[Blueboatman]

Does it ''load up''(judder) as the boat heaves up and down in waves then ? Does it vibrate or leak at certain rpm?

 

[boatmike]

Safe answer is yes of course, but I would only advocate replacement if you are experiencing vibration.

 

[Poignard]

No vibration and no leak through stuffing box.

The background to this is that there is a leak around the threads where the inboard bearing screws onto the sterntube, caused by failure of the thread sealant. Whilst attending to this I have removed the shaft and I noticed the worn areas and decided to measure them.

 

[Blueboatman]

Consider yurself a lucky man,the beer tokens can remain as,er,beer tokens then?

 

[nedmin]

Can you turn it round?End for end.Or will the worn section go on the seal?

 

[nedmin]

Sorry twisterowner,Think I,m going mad forgot about the taper for the prop!!! Just been working all afternoon getting Xmas lights to work bl--dy frozen must have effected my brain!!

 

[michael_w]

Get a quote for replacement it may be cheaper than you think. I replaced a 1" diameter shaft, 5' long 2 x tapers and keyways + thread on the prop end in 2003 for £110.00

 

[Norman_E]

Round steel is usually pretty close to nominal dimension as supplied, but often measures .0005" to .001" undersize. Your 7 thousandths wear is not much, and so long as it has not worn out of round, it should not be a problem. If there is appreciable slop in the bearings, they have probably worn more than the shaft. As an aside shafts should not be made from centreless ground stock, as this can often measure the correct diameter at all points yet be significantly out of round, leading to rapid wear. Such stock frequently has three lobes (in cross section) rather like the multi lobed 50 pence coin, Such a section can be measured with a micrometer at any position and give the same result, yet be quite triangular, to the detriment of the bearings.

 

[neil_s]

My prop shaft started rattling last season. There is 20 thou wear in the shaft and 40 thou wear in the bearing. I think you have a bit to go yet!

Neil

 

[Poignard]

Thanks for all the useful advice, gentlemen.
Now for the hard part - choosing which to follow!

 

[ccscott49]

7 thou wear is nowt! renew the cutlass and go back to the bar!

 

[seaesta]

If it does wear then you can fit one of those spacers at the flex coupling that lengthen the shaft for fitting a rope stripper (look at the Stripper/Spurs websites). You can then wear out a whole new section !!
Martin

 

[Poignard]

Nice idea [haven`t heard of that device before] but the rudder`s in the way!

 

[Heckler]

No