Grinding the lip off a stern tube

MoodySabre

MoodySabre

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My boat stern tube has a lip on it and I want to grind it off in order to fit a Volvo seal.

Given that there is not a lot of room, particularly underneath, what would be the best thing to use? I have a Dremel. Or coarse sandpaper. I'm not sure how hard this will be. I'm not cutting it off because that would make the tube shorter.

Should I then re-finish the 'raw' edge with epoxy?
 
For metric shafts different seals are made for metal or resin stern tubes. The latter are bigger in diameter than the former. To see the difference take a look at the RMTA seals here http://www.sillette.co.uk/price_pdf_files/tides_marine_shaft_seals.pdf In my opinion they are just as good if not better than the Volvo ones, and cheaper. If the larger size will go over the lip on your tube, just wrap the tube behind the lip in self amalgamating tape until the seal is a good tight fit before clamping it.
If you are going to try and file off the lip on your metal tube be aware that it was probably formed by expanding the end of the tube so filing it down will leave a thin and probably sharp edge, so you will probably end up having to shorten the tube to get rid of the sharp end.
 
If I was doing it, then depending on how much material I had to remove I would probably use either a rasp and then a file, or a power file:

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With the metal-cutting band fitted this is great for reshaping GRP, for bevelling hole edges for example.

Pete
 
In that case you will probably have to file it off, for which a short but fairly coarse (2nd cut) hand file is probably the only tool you can work with in the likely confined space. Do measure the shaft and the outside diameter of the tube first, to ensure that you can get a Volvo or Eliche RMTA seal to fit. If its an Imperial shaft and a GRP tube that might not be possible. As regards the actual seals my boat had a well worn but still dry Volvo seal and I replaced it with the RMTA version which is easier to grease and does not need to be burped on launch because it has an open ended tube attached to the water feed point and taken well above the waterline.
 
Just asking , apols for slight thread drift.

How do you grease the RTMA seal , does it have a convevtional grease nipple ?
 
Not a grease nipple but a covered hole the takes the end of a tube of silicone grease. You just squeeze some in from the tube and then replace the cap into the hole. It works very well in practice, and because there is no great pressure involved it does not need a grease gun.
 
MoodySabre said:
My boat stern tube has a lip on it and I want to grind it off in order to fit a Volvo seal.

Given that there is not a lot of room, particularly underneath, what would be the best thing to use? I have a Dremel. Or coarse sandpaper. I'm not sure how hard this will be. I'm not cutting it off because that would make the tube shorter.

Should I then re-finish the 'raw' edge with epoxy?
Click to expand...

Why not put a sleeve over the stern tube and keep the lip. then buy a larger diameter seal?
 
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