On Wed, 7 Mar 2012 22:11:25 -0500, "Flying Pig"
wrote:
Hi, all,
from another, earlier:
I can't quite tell what it looks like above the pitting.
Can you extend the threaded pipe higher where the packing gland goes on
and just make the packing gland higher so you are at a smooth spot ?
It looks like you have the room from the pictures. Have a pipe made
and attach it to the existing pipe with a coupling.
Yes, I might use either both a coupling and a nipple, or a machined-to-fit
single piece to extend the ~3" higher. Either one could have a zerk fitted
before installation, which would help.
However, the higher it gets, the more contortionistic (it's already
interesting) it becomes to renew the gland, later, given the big square
plates in the way (see some of the photos to see what I took off to get to
it)...
A possible solution - I've deleted your old message with the URL for
the photos - is to modify the boat in some manner as to make it easier
to get to the rudder gland. It may sound radical but my present boat
has drop in boards that make up the bed surface the mattress rests on.
Just haul off the mattress and lift out the boards.
and
There are several possible cures.
They used to, and likely still do, make a "dripless" gland packing
that was some sort of soft plastic substance what you packed the
bearing with. It "squished" enough to make the gland waterproof and
seemed to stay in place for years. West Marine used to sell it, and of
course it was available elsewhere. Used in a rudder shaft gland as
apposed to a propeller shaft gland it might be satisfactory.
The clay stuff can be murder, later. Seems like grease is a better
solution. In one of the forums I came across a very detailed look at
packing glands, packing materials, and the like; the clay stuff has some
serious drawbacks...
I have read that, on the other hand I've met people that swear by it.
But regardless, the rudder doesn't move as much as he propeller shaft
it might work on a rudder shaft while being less satisfactory on a
prop shaft..
They make a black impregnated packing that the seal shop that I
patronize tells me will last for years even on a pitted shaft. I used
it on a pitted propeller shaft on a power boat and a trip from
Singapore to Phuket, Thailand didn't show any leakage.
That might be of interest. Do you have a product name? I think I may have
the pits problem solved, one way or another, but not having to do the
packing any more often than absolutely necessary is appealing to me,
regardless of the solution I choose. The packing I've been using is, in
fact, black, and is teflon impregnated. Of course, the shaft rotates (well,
moves back and forth) at a very slow speed, but still has that problem of
the pits wearing it out. In the end, I had a small, constant, stream from
the gland tightened as far as I could make it go with a large pipe wrench
(constricted movement and access, as you might imagine from the pix)...
No. I probably never knew. It is a Singapore shop that I visit every
year or so and I had just bought a small motor cruiser. I mentioned in
passing that I had a problem shaft and he pulled out this "black"
stuff and recommended it. As I usually buy several meters of various
sizes of packing when I'm in the shop I don't think it is a matter of
"sell the guy something" and he probably did have a customer that
recommended it.
Years ago stuffing boxes with a lubrication system were common. Often
times with a "grease cup", but sometimes with a simple zerk fitting it
allowed injection of grease to lubricate the old time flax packing. If
one injected waterproof grease periodically it would likely reduce or
eliminate leakage.
I'd hope that I would not have to continously inject something, as the
interesting links below suggest :{))
The last boat I had with a grease lubricated stuffing box had a grease
cup attached to it. I used to give the cup a turn every few months, as
I remember. Never had any leaks nor any grease squirting out.
But really, if you go that route you just screw a hose into the gland
and run it wherever you want. Bleed it before you start to pump
grease. With a hose you ~could~ be sitting in the cockpit greasing
your rudder :-)
See drawing of gland: http://royalpurpleindustrial.com/prodsi/cap.html
Better lubrication: http://www.gouldspumps.com/pag_0011.html
That looks like it might do the job. Wonder if I could get just a couple of
ounces??
I would guess you might have to settle for a pound or so.
Finally: while, of course, the ultimate solution is to replace the
rudder & shaft assembly :-( is it possible to rebuild the packing
gland installation so that the gland falls above the damaged area?
With a hose perhaps, similar to most propeller shaft glands?
Yes, that's one of the potentials. Use a packing gland hose to extend, and
a nipple to accept the the nut currently used. Of course, I'd have to turn
a bevel into the nipple to provide the seat for the packing material. Or,
as above, a coupling and a nipple. The hose, if long enough (see
difficulties in access the higher it goes for discouragements), can be
shortened in the event of repeated corrosion (bring the gland down to
unaffected shaft).
I wouldn't do that. After figuring out how to attach the hose to
whatever you have now, I'd buy a proper gland to put in the other end.
I told you that doing it the cheap way is not always the lowest cost
way :-)
The same concept can be used in the form of a dripless, but that would
likely put it even higher. In any event, I'd have to get the rotating part
above any faults for it to be watertight. In this case, that means about 3"
or so.
I can't see, but is the gland acting as an upper shaft "bearing", if
not, it might be possible to make an extension for the present shaft
that clamps on the top of the shaft to mount the quadrant and various
rudder indicating senders and simply raise the stuffing box.
I was only commenting on the bearing. On my last sailboat the rudder
had no bottom bearing and the shaft was supported only by the rudder
tube and stuffing gland..
No, it's not. The delrin rings in both portions of the square plates are
the bearings. There's no room above the shaft without entering the berth
space, so extension (never mind the keyway slot and the opposing slot to
allow engagement of an emergency tiller, which, based on the marks and
deformation of the slots, has been done at least once in the past; I had to
peen the defects created in the slot sides in order to get the bearings and
control arm off) wouldn't work, either...
How much space above the berth? You might raise it. The sailboat I
mentioned above had only a little headroom over someone sitting in the
berth. To be frank we never really noticed the head room in over ten
years of living on the boat.
Of course, the ultimate fact is that whatever you do, other then
sticking more whatever in the gland, which didn't work, any final
solution you decide on will probably cost you money.
Heh. Nothing in boat$ doe$sn't cost money. And, I already have been using 4
instead of the typical 2 or 3 rings of packing material...
There isn't really any typical numbers of rings. the correct number is
enough to fill the box :-)
Addendum: I just happened to think of one more possible solution. You
might try shrinking a section of "shrink tubing" over the shaft in the
gland area. this is a shrinkable plastic sleeve used to insulate and
waterproof electrical connections. Initially it is large enough to
slip over the joint and then you shrink it by heating with a hot air
gun. Comes in 3 foot lengths, I believe.
If you use it do go to a commercial electrical shop and get the type
with the glue inside - they will know what you are talking about. It
is much more robust then the hobby shope stuff. Be aware though that
the industrial stuff takes either a commercial hot air gun or a gas
torch to shrink. Not the hair drier like the hobby shop stuff.
Thanks for the thought. I don't know that such would stand up to the
stress, and, likely, would depress into whatever remains of the pits I've
been working on, creating opportunities for failure of that material.
What stress? You have said that the stuffing box did not act as an
upper bearing so any stress would come from the packing rubbing on the
plastic. Teflon impregnated packing rubbing on a PTFE covered shaft?
(PTFE, sold as Teflon by DuPont Co)
The good news (relatively, of course) is that even after my most recent
aggressive run at it with a wire wheel, the pits are much better. However,
anything other than fully smooth just delays the issue. If I were to do any
form of sleeve, it likely will be the SS one mentioned in my other response,
courtesy of the Morgan mailing list member who alerted me to it.
One comment here. If you install the stainless sleeve can you get the
rudder off? Is there is room in the rudder tube for it to slide out?
Various other suggestions are still coming in, and I haven't heard back from
the SKF folks yet to confirm that it could work in my case.
Still, lots of options, one or more of which are likely to do the trick;
I'll just have to make my choice.
L8R
Skip
--
Cheers,
Bruce