Getting the coupling back on the shaft... in the water - SailNet Community
LinkBack Thread Tools
post #1 of 5 Old 11-22-2009 Thread Starter
PNW transplants in CA
paul77's Avatar
Join Date: Jul 2007
Location: Redwood City, CA
Posts: 76
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
Getting the coupling back on the shaft... in the water

I decided to pull our prop & shaft with the boat in the water, so we could get both shaft and prop checked due to a vibration. This turned out to be a good bet, since it was two weeks turnaround to get the maxprop to/from PYI, now rebalanced and shiny as new.. (we live aboard, so two+ weeks on the hard would be somewhat disruptive)..

I've been test fitting the reassembly before it goes into the water, and I cannot get the coupling back on the shaft.

The shaft guy said that on the hard they usually attach the coupling halves and then use force to bang the shaft back in. He wasn't familiar with the proper procedure in the water.

The coupling is a walter-style split coupling. I've been trying to work it onto the shaft, but it won't go on very far.

I suspect that I need to just bend the halves further apart, I have worked them a little bit by hammering a pry bar in between them. It was on the shaft really tight and was a pain to get off to begin with.

Anyone have any advise or ideas on how to approach this?

Shaft couplings always seem to be a source of pain... I would even replace the coupling if there's a style that is easier to work with. (like maybe something that splits into two pieces?)
paul77 is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #2 of 5 Old 11-22-2009
Senior Member
Join Date: Mar 2008
Posts: 890
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 10
I frequently do shaft couplings on pumps and electric motors. This stuff takes a LOT of patience! What I usually find is a couple of small dings. When a shaft gets dinged the metal from the dent got pushed up into a bump along side. I find a new single cut mill file and some very gentle filing does the job. It sometimes takes as much as an hour. You may also find the shaft raised a bur in the coupling. A three corner scraper is good for taking care of that. If you don't have one you can make a serviceable one from an old three corner file on a bench grinder, then stone it.

I was just teaching a new guy how to do it back in the spring on a 75 hp electric motor and pump. He didn't think it would ever go. But a half hour later it slid on like silk. Any time someone tells me they just use a hammer I know there will be hell to pay later. Machinery has a VERY long memory about being abused!

Gary H. Lucas
GaryHLucas is offline  
Quote Quick Reply Share with Facebook
post #3 of 5 Old 11-22-2009
Maine Member
BELLATRIX1965's Avatar
Join Date: Jan 2007
Location: Penobscot Bay Maine
Posts: 181
Thanks: 2
Thanked 0 Times in 0 Posts
Rep Power: 11
Patience and precision. . .

I'm with Gary -

It's easy to damage a shaft / hub and not realize it. Since you have the parts in your hand, I'd get the shaft into a lathe and polish it in way of the coupling fit (with fine emery cloth). Also, it probably wouldn't hurt to ream the I.D. of the coupling - preferably with a spiral reamer (so you don't get hung up in the split). You are wise to test-fit the parts in advance. Remember, this is supposed to be a clearance fit - you should not have to use a hammer! If need be, ream out the hub a few thousandths larger. Good luck!
BELLATRIX1965 is offline  
Quote Quick Reply Share with Facebook
post #4 of 5 Old 11-23-2009
Courtney the Dancer
jrd22's Avatar
Join Date: Nov 2000
Location: San Juan Islands., WA, USA
Posts: 3,968
Thanks: 5
Thanked 30 Times in 29 Posts
Rep Power: 17
Ditto what has been said above. The coupling should slide on smoothly. If it doesn't then check the shaft very carefully, you will probably find a few small dings that you may not even be able to really feel. As suggested above, a fine file or emery cloth and some time will usually fix it. I would be careful about prying the coupling apart very much, unless you want a new one.

SV Laurie Anne

1988 Brewer 40 Pilothouse

jrd22 is offline  
Quote Quick Reply Share with Facebook
post #5 of 5 Old 11-23-2009 Thread Starter
PNW transplants in CA
paul77's Avatar
Join Date: Jul 2007
Location: Redwood City, CA
Posts: 76
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
I did sand away the layer of rust on the inside of the coupling so that is smooth metal now. Gary -- I can see where there's scoring on the inside of the coupling from the set-screw dimple in the shaft. I'll check if I can get rid of that.

Will also try the emery cloth or a file on the shaft and see how that goes. There wasn't anything obvious that it was catching on. I can get it on maybe 1/8" and thats it.

The shaft guy I had check the shaft when it was out thought that it was okay for it to be tight, so I may take it to another shop to get a second opinion and see if they can do anything.. There's not a tonne of space to work with when the shaft is back in the boat, so it's worth it to me to ensure this goes smoothly

Bellatrix -- as for reaming the coupling out, not a bad idea though I'll probably hvae a shop do that since I don't have the tools and I want to make sure I don't affect the runout or end up with the coupling off center. FWIW even a few thousands can be significant here.

Thanks for all your replies.
paul77 is offline  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Rethinking Sinking David Schaefer Seamanship Articles 0 08-03-2004 08:00 PM
Gifts from the Rain Gods Doreen Gounard Her Sailnet Articles 0 03-18-2004 07:00 PM
Basic Thoughts on Tides Jim Sexton Learning to Sail Articles 0 11-17-2003 07:00 PM
Water Pump shaft on the move... ikent Gear & Maintenance 0 10-07-2003 04:20 PM
Understanding Tidal Currents Jim Sexton Her Sailnet Articles 0 08-05-2003 08:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome