Great project weekend!

[DannyS]

Well, after three years of trying, I finally installed my new cutlass bearing. The first attempt I was hoping to pull the prop, then use a homemade bearing pusher that would push the old bearing out with the shaft in place. I failed miserably, never even got the prop off. The second attempt I went in with more conviction. I got the prop off (although with questionable methods), I fought the coupler from the shaft after a three hour battle it finally cried "UNCLE" and gave in... however, with the free shaft, I was finally able to pull the shaft out far enough to find that the rudder HAD to come off as well. I thought for sure I'd be able to sneak it by but no. So everything went back together, mission failed again. This year, I had removed the rudder last fall to fix some delamination so I had no excuse not to get it done, the only hiccup was getting the coupler off. It was again a hard fought battle and the coupler put up a good fight, but it relented and came off.
Another kudos out to Maine Sail for his articles on removing the coupler from the shaft (I've used that one twice now) and the article on removing the bearing from the strut. My guess is that none of these projects had ever been done over the life of this boat ( 1985 O'day 35) so she's a happy boat. The last thing to do was to reassemble the bearing, and driveshaft assembly, reinstall the rudder which went without a hitch and now we're ready for spashdown!

 

[Maine Sail]

Danny,

Don't forget to replace the coupling if it was badly rusted. If it fought that hard the layer of rust that broke free was likely your fit tolerance. Couplings should be fit with a max fit variance between shaft and coupling of .001". That is the worst it should be. Most reputable shops fit into the ten thousandths or light tap or light press fit. Having a coupling that just slides on can have negative consequences to your shaft and can ruin it.

Having a new coupling fit & faced now is cheap money compared to a mid-season haul out and a new shaft and coupling..

 

[Ed Schenck]

Not following you Maine. Danny had trouble getting the coupler off of the shaft, right? You are saying that rust was the "glue"? Between the shaft and the coupler? I would have expected the shaft and coupler to be clean and shiny. Always thought it was simply the combination of the keyway and the way metals grab. Same with getting a prop off, the shaft and prop always look clean.

 

[DannyS]

Maine, I had a good snug fit going back on (both years). Let me ask you this though...I was surprised how hard it was to remove this year since the coupler was off just a year ago. I removed my Magnesium (we're in Lake Superior) and need to replace it before splashing and this was the worst I'd ever seen as far as the pitting ans sacrifice goes. Would that have anything to do with the mated surfaces of the coupler and shaft fusing together to make it so tough to remove?
Again, thanks for your help!

 

[Maine Sail]

Maine, I had a good snug fit going back on (both years). Let me ask you this though...I was surprised how hard it was to remove this year since the coupler was off just a year ago. I removed my Magnesium (we're in Lake Superior) and need to replace it before splashing and this was the worst I'd ever seen as far as the pitting ans sacrifice goes. Would that have anything to do with the mated surfaces of the coupler and shaft fusing together to make it so tough to remove?
Again, thanks for your help!

That's excellent! Just be sure your snug fit is not a burr from one or both of the set screw holes. In fresh water, especially with a bronze shaft, there is often minimal to no rust between shaft and coupler but on the ocean there is nearly always a layer of rust even often on bronze.

The shaft anode should have no bearing on how the coupler came off. Often times slight movements of the shaft and coupling create high spots on the shaft at the set screw dimples making the coupling grab and bind even with no rust.. Any high spots on the shaft should be removed before fitting the coupling as they can give the appearance of a snug fit, without it actually being one.

 

[Maine Sail]

Not following you Maine. Danny had trouble getting the coupler off of the shaft, right? You are saying that rust was the "glue"? Between the shaft and the coupler?

Yes often times the steel coupler rusts to the shaft and when you break it free you lose fit tolerance. Have I seen clean un-rusted ones? Sure, but so rarely on the ocean, that it is like the proverbial needle in the haystack.

I would have expected the shaft and coupler to be clean and shiny. Always thought it was simply the combination of the keyway and the way metals grab. Same with getting a prop off, the shaft and prop always look clean.

Not the case on the vast majority of couplings. A prop is bronze and on a tapered SS or bronze shaft, no rust. A coupling is machined steel and rusts...

This coupling was less than one season old and already had a decent layer of rust between shaft & coupling. You can see it left behind on the shaft. The older they get....

 

[Bob S]

Could a coupler be made from stainless? Is it just too pricey or is there other factors that have to be considered in order to do that?

 

[thereisabelle]

if your having a new shaft made insist on aqua met. no off the rack stainless! total indicated run-out not to exceed .0015. spot heat and quench before finishing the taper and threads if needed. steady rest where the bearing rides and face the coupling on the shaft ( nib for set screws ) preferably with the tail end in a collet. chucking on the shaft pinches and causes runout. 20 yrs. machine shop. 1" x 2' to 8" x 24' they have to run " tender and true." with the possible exception of the LA. mud shaft. lol
this is touching on the basics. the are other important considerations... keystock fit,cotter pin,even shipping. some folks like to safety wire the square heads on the set screws together.

 

[kloudie1]

Isabelle.. YUP ! I agree with your specifications.. Now the problem is finding a commercial machine shoppe with real machinists who will (not can; many can) work to those specs.. They are getting kinda rare..
We'd sometimes put a layer of tungsten carbide where the steady bearing was if the erosion potential was high...

 

[Ken Honeycutt]

Forgive my ignorance , but where can I find Mainsails' article on pulling the coupler? I started to install a PSS dripless shaft seal but I stopped after realizing its not a good idea to use brute force and anger to pull the coupling.

 

[Stu Jackson]

Try this: http://www.pbase.com/mainecruising/stuffing_box&page=1

Wander around the site to find your topic.

You could also click on the (less?) obvious LINK in his signature in his post above:

_________
-Maine Sail

Casco Bay, Maine
Canadian Sailcraft 36T
Our Sailing Photo Galleries (LINK)

 

[Ken Honeycutt]

Thanks Stu, guess I was too focused on looking at the pictures (been a tough day).

 

[thereisabelle]

the name thereisabelle came from our survey report... my wife and i were sitting at el mezecal looking the report over and noticed the surveyor checked no beside ships bell?
we both said at the same time " there is a bell!" back to shafting... when i use to machine and weld, the job was bestowed on me to make flakeing mill shafts for a major cereal co. grrrrreat! it envolved undercutting and building up with #12 stellite in two areas. one close to the end the other 12 - 14" from the other. whew! all said and done the built up areas had to be ground to +.000 - .001 with t.i.r. of .0015 i left there with my secret of how to control the live center...i'll tell my grandson someday.