Shaft wear at stuffing box

dratsea

dratsea

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Seasons greetings to all (and esp Vyv),

I have a 1.25 inch shaft going through a Buck Algonquin stuffing box. I have just changed the hose and the stuffing and can see some wear at the point the shaft goes through the stuffing box. Over the last 20 years and some 5000 hours it worn a slight waist where it goes through the packing. Measured with micrometer it has lost just under 1/16th inch, so at the narrowest point is now just over 1 and 3/16inch instead of 1 and 1/4inch. Back in the water, runs nice and smooth and with the new PTFE stuffing dry at rest but with a regulation drip per min when running. I am going to do a big overhaul next year. At what level of wear should I consider replacing the shaft?

Searching back over last few years gives plenty of info about DSS, Volvo seals, shaft alignment and everything I always wanted to know about cutlass bearing but I could not find any threads to guide me on this. Any views, experience or even pointers to a thread with the answer?

Many thanks and Merry Christmas to all

John
 
dratsea said:
Seasons greetings to all (and esp Vyv),

I have a 1.25 inch shaft going through a Buck Algonquin stuffing box. I have just changed the hose and the stuffing and can see some wear at the point the shaft goes through the stuffing box. Over the last 20 years and some 5000 hours it worn a slight waist where it goes through the packing. Measured with micrometer it has lost just under 1/16th inch, so at the narrowest point is now just over 1 and 3/16inch instead of 1 and 1/4inch. Back in the water, runs nice and smooth and with the new PTFE stuffing dry at rest but with a regulation drip per min when running. I am going to do a big overhaul next year. At what level of wear should I consider replacing the shaft?

Searching back over last few years gives plenty of info about DSS, Volvo seals, shaft alignment and everything I always wanted to know about cutlass bearing but I could not find any threads to guide me on this. Any views, experience or even pointers to a thread with the answer?

Many thanks and Merry Christmas to all

John
Click to expand...

engine power?
reduction box ratio?
max rpm ?

shaft material?

then others can help !

merrry christmas
 
Thanks Norman,

Thanks David, it is a 4JH2E so in answer to your questions:

david_bagshaw said:
engine power? 50hp
reduction box ratio? about 2.5 ahead, 3 astern
max rpm ? 2500 engine so 1000 shaft
shaft material? SS
then others can help !

merrry christmas
Click to expand...

Hope that helps others,

John
 
dratsea said:
Thanks Norman,

Thanks David, it is a 4JH2E so in answer to your questions:



Hope that helps others,

John
Click to expand...

imho you will be perfectly ok at that hp.

we ran 16 foot bronze 1 1/2 shafts in 3 bearings, lead stuffingbox, outboard cutlass, A bracket cutless bronze at 84 bhp 2.1 reduction with much deeper packing groves. certainly did not worry about shaft failure, just the grooves moving when astern, encouraging packing leaks.

others will be along with a calculation.
 
if feasible (& really neccessary?), adjust flexible hose lenght to bring packing gland onto new shaft metal. your yonks away from a new shaft I'd have thought..
 
Happy New Year,

Will update this message if at some time I do I have problems but agree with forum vote and going to leave it as is.

Thanks to all,

John
 
I agree. For a shaft gland the critical issue is whether it leaks or not. A small wear groove should not affect sealing as the packing will expand into it. It should be possible to tighten carefully, monitoring the temperature of the housing, until the drip stops completely.
 
Unless your boat is one of these flat bottomed bilgeless glorified dinghy things, stick with the tried and tested good old fashioned stuffing box.:)

In a past life, I had a lot to do with mine water pumps. At one point we used many of two similar nuisance-water pumps, one with conventional stuffing boxes, and the other with a modern seal. The seals gave lots of trouble, while the ordinary packing type, just went on and on. All the main, high capacity, high pressure pumps had conventional stuffing boxes, using graphite, and latterly teflon packing.
 
sailorman said:
my stuffing box is 34 yrs old no leaks, little wear & bullet proof
Click to expand...

Which is great and, aside from the temptation to relieve myself of the maintenance of one, I'd leave a stuffing box which works perfectly well alone too, but dratsea's is dripping and wearing his shaft to the extent that he's concerned enough about it to ask here.
 
Last edited:
Simondjuk said:
Which is great and, aside from the temptation to relieve myself of the maintenance of one, I'd leave a stuffing box which works perfectly well alone too, but dratsea's is dripping and wearing his shaft to the extent that he's concerned enough about it to ask here.
Click to expand...

Read the original post. Dratsea's is dripping "at the regulation one drip per minute, when running, and dry when stopped". Where's the problem?
 
Simondjuk said:
In the longer term, could change to a face seal and do away with all your shaft wear, adjustment, dripping and maintenance issues at a stroke.
Click to expand...

Yea, yea....and read the Forum comments about the multitudinous problems that "no maintenance" face seals give rise to..
 
NormanS said:
Read the original post. Dratsea's is dripping "at the regulation one drip per minute, when running, and dry when stopped". Where's the problem?
Click to expand...

As I already said, in the original post, which I read otherwise I wouldn't know, there was concern about shaft wear. I'd not be worried by it, but he was. A face seal would provide a solution to that concern.

As for the drip, personally, I'd rather not have a drip. I like my engine bay clean and dry so that I can immediately see when something is leaking.

I couldn't really care what he seals his shaft with, I'm not on commission from PSS and have nothing against stuffing boxes. I simply suggested a cheap, maintenance free, adjustment free, non shaft-wearing and drip free alternative which I've seen work without fault in extended use. You on the other hand feel inclined to advise someone against using a perfectly good, and perhaps superior, option when your experience of PSS seals on yachts is I presume, since you only reference mine pumps, absolutely none.
 
Last edited:
SHUG said:
Yea, yea....and read the Forum comments about the multitudinous problems that "no maintenance" face seals give rise to..
Click to expand...

I've not seen many posts mentioning problems with PSS seals. Just the opposite, in fact.

So I can be aware of potential issues, could you point me to a few please?
 
Simondjuk said:
As I already said, in the original post, which I read otherwise I wouldn't know, there was concern about shaft wear. I'd not be worried by it, but he was. A face seal would provide a solution to that concern.

As for the drip, personally, I'd rather not have a drip. I like my engine bay clean and dry so that I can immediately see when something is leaking.
Click to expand...

Thanks Simon, you are right in that my concern was the wear rather than any dripping. I also agree with you about a clean engine bay and the tray under the engine is clean and dry which is not surprising as it is about 10ft from the stern gland and has no connection with the bilge.

Thank Viv and Norman, agree with Norman's comment about mine pumps.

For info, long keel, deep bilge and keel stepped mast so always get a bit of wet in the bilge, down mast and the anchor locker drains to the bilge. I could tighten up the packing box a bit more and stop the drip per minute while running but I would like to think this is reducing any further wear.

dratsea
 
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