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Passport111

Longitudinal Rudder movement

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We've had our boat (1985 Bianca 111 with balanced spade rudder) now for 3 years and this year when we put her up for winter storage I noticed a little play in the rudder.

 

I was interested to look when she came out of the water as I could hear a bit of a thump and felt movement in the rudder stock when in larger waves from the aft quarter towards the end of the season.

 

The movement is only for/aft (longitudinal) and there is none laterally. I would estimate that the movement at the bottom of the rudder is about an inch when I pull aft.

 

I don't expect anyone to be familiar with this boat or its associated rudder mounting hardware. However, I'm wondering if I could get some advice on the usual suspects when it comes to diagnosing what is failing. Could this be something that just needs adjustment or am I likely looking at dropping the rudder and replacing the bearings?

 

 

 

 

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First suspect is the mounting of the bearings (whatever they are- maybe just a fiberglass tube) to the hull/deck/cockpit floor/etc. Take it apart, take pictures, and chances are the fix will be relatively easy and successfully get the play out.

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Thanks. So if I understand correctly its potentially the bearing to hull attachment and not necessarily the bearings themselves. There seems to be a sort of bearing/bushing flush with the hull that the rudder stock passes through entering the hull. I did see this move a bit. Would it be epoxied in normally or mechanically fastened?

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1 inch at the rudder tip is quite a lot of movement. You need to investigate what kind of bearings are in there and how are they (were they?) attached.

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Take it all apart and take pictures. You may end up with some new delrin or other mechanical pieces, and/or either re-epoxying or re-5200-ing something in place. It is probably cramped and crowded back there and will be painful to disassemble. You will be glad you did. While you are at it - now is the time to repair and replace anything else in the steering system that is not working correctly or has worn - replace cables, check all the bolts, etc. Preventive maintenance on the steering system is 75% labor getting back there and taking the stuff apart, 20% labor to fix whatever needs fixing, and maybe 5% cost. Hence go into the take-apart with the view that you are going to make it good for the long-term. As you are cursing how cramped and inaccessible everything is, just keep congratulating yourself on making sure you never ever have to go back there while the boat is under way.

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Rudders if that time period usually had delrin bearings, as said above. It is fairly easy to change, but you must be able to totally remove the rudder, ie you drop it - you may have to dig a considerable hole in the ground.

 

For a new bearing you should select some better plastic. There are specialists making rudder bearings, use one of those, and nut j6dt the closest machine shop. One has to dimension the new bearing keeping inmind the (very minor) swell from water absorption.

 

When the rudder is down you must measure the diameter of the stock (where yhe bearing is). Measure with a caliper, see to get an exact value. You are likely to find that the rudder stock is no longer perfect symmetrical (most are not after some 20++ years of use; you also have noted some play in one dimension and not the other). You may have to fix this in one way or the other. Jefa homepage is very instructive.

 

If you replace the old bearing (assuming delrin) with a similar that will cost $ 10 - 30.

If you go for a superior material that will cost you abot $50.

If you gave to use Jefa equipment - more expensive.

 

Been there, done that.

 

/J

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PS: Bianca was a high qualty boatbuilder. The 111 is a very nice mid-size sailboat, fast for its time. Designed by Elvström & Kjaerulf. Take care if it!

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Good advice above. Just be prepared to pay a lot more than 10-50$. Just replaced mine, Solimar ertalyte ball w/ needle bearings.

 

Not sure what the construction is but also check and service the top bearing.

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Thanks for all the advice. We hope to be seeing some warmer temperatures here soon so I'll be digging into this as soon as possible.

 

Yes we love the Bianca. She is in incredible condition and we are taking very good care of her and will continue to do so!

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Update: I also noticed that the rudder can be pushed up about 1/4". Is this normal? As I mentioned previously, there was some cluncking from the rudder this past season when taking wave on the quarter. I think it was this up and down motion of the rudder and not the lateral play..

It also seems when I push the rudder up, the lateral play is reduced. I have pictures but can't figure out how to attach them.

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Well, it may happen. I still think your rudder has two bush bearings, an upper and a lower, the latter one at sea level. Below the lower bearing, on the outside/underside of the hull, there might be, or might have been, a plastic ring so the rudder should not wear directly on the hull. This ring could be seen as as a bearing if one wants to. Thickness 5-10 mm. As the ring is exposed to all kind of things: UV, saltwater, oils, mechanical wear it breaks after some years, leaving a gap. And the rudder may move up a bit, now and then.

 

As another explanation the fastener, clamp, which prevents the rudder from falling down has slipped somewhat, the rudder has then actually moved down some distance and by pure luck stayed there - so far. The clamp from that period is often made in two halves whichare bolted together around the rudder shaft. If you have wheel steering then that mechanism is connected to the clamp as well.

 

A third theory .... the lower bearing is no longer attached to the pipe in which the rudder shaft is running.

 

The first theory is most likely.

 

In any case, the should not be any noticeable horizontal play in the rudder.

 

Instead of theorizing I suggest you take a digital camera, a mobile phone with camera works fine, and take many photos on how it looks from whatever angle outside, inside abd everywhere around the rudder. Cost you nothing and you may have use of it later when you re-mount the rudder with the new bearing.

Then you start to prepare to dismount the rudder. Do that very soon.

And then execute as described earlier.

 

/ J

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I dropped the rudder yesterday after haulout for the season and was very surprised at what I found.  Not all bad but surprised nonetheless.  

Starting at the end of last season and all this season there has been a bit of a "thump" with a quartering wave pattern from the stern.  Upon inspection after haulout last season I noticed a bit (1/4") when pulling the bottom of the rudder fore and aft (not so much laterally).  However, with a bit of a heave, I could lift the rudder about a 1/4-3/8" which accounts for the "thump".

At first I thought the top bearings maybe needed to be replaced as the bearing being worn would let the rudder down a tiny bit. I replaced at the beginning of this season with new Torlon (no difference but good to replace the Delrin anyway).  Now, after talking with some people I think there was a bake-a-lite or some other type of plastic spacer/thrust washer that sat between the flange of the lower bearing and the top of the rudder that just disintegrated or fell off.  So my plan is to get some UHMW spacers and that should fix the "thumping".

Now the issue with the play in the rudder.  I was expecting the bottom bearing was a plastic busing but to my surprise there is a bronze/stainless bearing race pushed into the rudder tube (ruder tube looks to be G10 or something smooth) and stainless roller bearings that ride on the shaft.  The top bearing is the shaft going through a bronze fitting in the aft seat with a race on top of the seat.  If you imagine this, the lateral forces are just handled with an interference fit between the shaft and the bronze sleeve but the real forces are to support the vertical forces with the race and cap wherein you'll find the new Torlon ball bearings.

Questions:

How to take up any slack in the bottom bearing?  This looks like a customer metal race so I'm not expecting to replace it.

Ideas on getting the race out?  I hate to open a can of worms or break something in the process but I feel this is the only way to test the fit with the bearing on the shaft and it would be good to re-bed it on the hull.

 

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Passport,

 

Thanks for your pics! Interesting, one learns every day. 

Some things one should really think about before acting. Take your time!

Propose you get a good caliper that can measure the shaft and the bearings. Problem use to be the shaft diamater is too large for ordinary calipers. You would need a precision in the order of 0.1 mm (or better ... but that is difficult without professional equipment with the usual shaft diameters). Looks like your shaft is in stainless, then not so large diameter. 
Measure many different positions (angels) - it is not unusual that the shaft and bearings are no longer perfect circular. As it looks to me you have 3 major parts: shaft, roller bearing and bronze part (fastened to the hull)

The gap between shaft and bearing should be in this order of magnitude (~0.1 mm), not more. Not unreasonable that there has been some wear with time. Also bearings must be replaced now and then - in your case you have to identify which part has worn down most and which part is most easy to change. I would not be surprised if it is the bronze part - that is a guess, it is many parameters and I do not know which is softest the stainless or the bronze - it is probably a special kind of bronze, often called something like bearing bronze (OK, that is a direct translation from Swedish ... ). If often has a oily feel. 

In summary I think you have to replace at least one part, probably the bronze part. A good mechanical workshop can probably make one - it is easy to work in bronze, but you have to see to that you get the right quality. Costs are probably moderate whatever you do.

Have I earlier recommended the Jefa web site? If not, take a look. Maybe not very applicable for you, but very instructive. 

BTW, with metal bearings there should be somewhere a nipple to inject grease. Probably on the shaft tunnel. In a most un-accessible part, somewhere. 

Best

//J

 

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Thanks for the response.  Yes I think the first step will be measuring everything.  I have a friend who should have everything so we'll get started soon.  

I'm very nervous to try and remove the bearing race in the hull as I don't know how it was fastened/adhered.  Again my friend works with these types of things on race cars so has a few ideas about heating and cooling to separate the inner race from the outer part.  Nevertheless, I don't want to damage anything trying to get it out and end up having to rebuild something that is very well built and will probably last another 30 years.

I would think there would be a grease fitting but have not found one yet.  I did't really seek it out per se but will now.  There is evidence there was grease there and it makes sense.  I did read recently that metal bearing in this application should not be greased but find that hard to believe.

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You can take up the play by reassembling with oversize rollers. However the race or shaft or both may be out of round at this point. Neither will be easy to get back round again as it is hard to get machinery to them. I'd probably be thinking in terms of replacing with a Jefa or similar. You may be able to pull the bronze out of the hull by heating and jacking it out (epoxy will release at 200 deg F or so). It could then be made round again in a lathe.  It might also be possible to chuck the rudder in a really big lathe and turn the surface true if it is damaged or egged. When you reinstall the bronze, you would either need to use the rudder, or a jig shaft made for the purpose, to get it potted in alignment with the top. 

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I hate to replace with a Jefa as it would be a major rework.  The existing system is strong and very well built.  The play is minimal but as these things go, now that there is play it will probably deteriorate.  

I guess I'll have to measure very well to start to see if I can determine if and what is out of round and then go from there.

Any sources for new rollers that you are aware of.  Would you stay with stainless or go to Torlon or another synthetic?

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Yes, to measure is to know!  

When I fixed my rudder bearings I found the shaft (Alu) had deformed slightly, not round anymore. As I had Delrin bush bearings I did consider rebuild to a Jefa - they have more than one type - but did not have time for it and just polished the shaft and got a new bush bearing. So far, works fine. 

New rollers - well, why don't you ask ... Jefa? They have roller bearings solutions as well, may have had similar questions from other Bianca owners. Personally I would have stayed with stainless rollers as it has worked fine for many years. 

It is also possible to contact Bianca, still going: http://www.biancayacht.com/home.aspx

Lubrication: Delrin and similar bearings shall not be lubricated, they are water lubricated. Metal bearings shall be lubricated, even if the bronze alloy to some extent is self lubricated. In the manual to my boat it is described how and where this should be done but I couldn't find where to grease on the boat,  Removing the rudder I realised it had Delrin bearings ie the builder had changed from bronze to Delrin without chaning in the manual. 

//J

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I would consider replacing the bottom bearing with a UHMP plastic bearing.  Our boat came with Delrin in 1981,we replaced with new Delrin a few years later, then replaced with new UHMP a few years after that. The boat still has the UHMP bearings that were put in around 1990 with no play in the rudder at all.  We use the boat extensively including lots of sculling around the dock, and the rudder has been removed and replaced many times.  I don't think you'll find any mechanical bearing that will last as long as that.

This of course will only work if the rudder shaft is round.  If it isn't, and you can't find a way to machine it back to round, you will have to consider one of the more expensive bearings that can account for the shaft being out of round.

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So after finally getting some advise from a gentleman in Denmark who had done this before, I went ahead and pulled the bearing race this weekend.  My heart is beating again.

What we have is a bronze bearing race press fit into a stainless sleeve that is molded into the boat.  Now I need to get a new bronze race machined, press it back in, and hopefully my rudder is good for another 30 years.

My question is, what kind of Bronze?  From the research I've done, there are 3 major types; bearing, silicon, and aluminum bronze.  Bearing is the softest (relatively) and so can tolerate contamination and lack of lubrication.  Silicon and Aluminum are harder and very corrosion resistant.  Clearly this is not an engine or transmission application.  The shaft will turn through less than 90 degrees, slowly, but have huge lateral forces and be in a corrosive environment.  

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Aluminum bronze would probably be the longest lasting, but if it were my boat I'd look at plastic. Unless you had a way to install a grease fitting. If you wanted to duplicate the material that came out, take it to a scrap yard and see if they have an Xray fluorescence gun. That will tell you in an instant what you have. 

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@DDW thanks for the suggestion.  

I've thought about plastic too but I figure if it worked before, why change.  I'd have to figure out how to secure the plastic in the stainless sleeve.  The bronze lasted for 32 years and the helm always had a nice light smooth feel.

So the Xray fluorescence can tell what type of bronze?  Fascinating.  I'll check into it.

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1 hour ago, Passport111 said:

@DDW thanks for the suggestion.  

I've thought about plastic too but I figure if it worked before, why change.  I'd have to figure out how to secure the plastic in the stainless sleeve.  The bronze lasted for 32 years and the helm always had a nice light smooth feel.

So the Xray fluorescence can tell what type of bronze?  Fascinating.  I'll check into it.

Bearing bronze should be somewhat oily when you touch it. One would guess that bearing bronze has been used but with boat builders you never know.  The bronze bearings are often thinner (thinner walls) than those made of plastic - otherwize I would recommend plastic (some UHDM or even more advanced) but that would probably require a new ss tube. 

Congrats to the bearing removal, btw. It is always good to do such operations as one learns a lot on how the boat is built. 

//J

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The nickel aluminum bronzes are the toughest and are also very corrosion resistant. Don't be replacing with plastic unless you're sure you have enough bearing surface area. Plastics are great - but are a lot weaker in compression (bearing) strength.

A good reference: http://www.norfolkbearings.com/products/nbmetal/NATIONAL-MARINE-NAVAL.pdf

 

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Some plastics these days outperform bronze. The usual P limit you see quoted for bronze is 4000 psi or so, Vesconite can be used at that or more and PEEK even much higher. They would press fit like bronze. I wouldn't replace bronze with UHMWPE without some calculation and some way to secure it. Looks like he's got about 20 sq in there so probably almost anything would work. Vesconite is being used in large ship logs and rudder posts in preference to bronze. But I understand the notion of it not being broke, so not needing to be fixed. McMaster has 954 (aluminum) bronze tubes in sizes like that, not even that expensive. Certainly less than a piece of PEEK which in 6" round is probably $200/inch. 

An XRF gun it a neat tool for analyzing metal - just point and shoot and you have an answer. I'd love to have one to wander down the "bronze" fitting isle of the chandlery. They are still running about $15K on ebay used though, so not an impulse purchase. Many scrap yards have them to make sure what they are buying is what it is claimed to be. 

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Cool. Never knew about an XRF gun. While my office doesn't _need_ one, it sure would be fun to have.

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I havent followed the thread.

 

be aware the rudder bearing wear fore and aft...prop thrust and water flow 

 

you, or a skilled machinist ,  would be wise to carefully measure  and verify that the rudder stock is round 

as for plastic bearing they work fine..the machinist must know the  properties and machine it to accept swelling 

 

vesconite is a good choice for the marine enviroment  ...ask you machinist for other options     https://www.vesconite.com/story/best-possible-material-rudder-bearings/ 

 

 

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I looked at the Vesconite and it is pretty remarkable stuff.  The website even had a calculator that gives the exact machining dimensions for a press fit. 

That said, I'm still going with bronze if for no other reason, the outcome and performance in the application is known.

I emailed Port Townsend Foundry and they recommended Aluminum Bronze (C63000) so that is what I'll go with unless I hear something overwhelming to the contrary.

Regarding out of roundness; that is my biggest worry.  I can't really do any thing about the rudder stock.  I can't really do anything about the stainless sleeve either short of pulling it out in which case I may as well go with a whole new rudder system.  I'm not sure if the bronze can be press fit round in a slightly out of round sleeve (like .001 or so) to make up the out of roundness but that would be the only option at this point. 

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Is the shaft out of round? I'd expect most of the wear to be in the softer bronze rather than the harder SS. If the stainless sleeve is out of round by 0.001, the bronze bearing will press in and simply conform to the sleeve. 0.001 is certainly nothing to worry about in this application. If the shaft is out of round, the clearance will need to be enough to accommodate, if it's too much you will have the same play you started with. The shaft could be trued on a really large lathe, otherwise you are into a complete rebuild of the rudder, and a new one is probably cheaper. You may have another option: the bronze bearing looks like it is thicker than it needs to be, so it may be possible to turn a thin stainless sleeve to go on the rudder (probably with Plexus or a Loctite bearing mount compound) and make the bronze bearing a bit thinner. Everything would be round and new again. On industrial equipment a "wear sleeve" is sometimes installed when new for this purpose - cut it off and put on a new one at rebuild time. Or, fix a plastic bearing on the rudder shaft, and have it turn in the SS sleeve in the hull. That would probably be good for another 30 years or so. 

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18 minutes ago, DDW said:

Is the shaft out of round? I'd expect most of the wear to be in the softer bronze rather than the harder SS. If the stainless sleeve is out of round by 0.001, the bronze bearing will press in and simply conform to the sleeve. 0.001 is certainly nothing to worry about in this application. If the shaft is out of round, the clearance will need to be enough to accommodate, if it's too much you will have the same play you started with. The shaft could be trued on a really large lathe, otherwise you are into a complete rebuild of the rudder, and a new one is probably cheaper. You may have another option: the bronze bearing looks like it is thicker than it needs to be, so it may be possible to turn a thin stainless sleeve to go on the rudder (probably with Plexus or a Loctite bearing mount compound) and make the bronze bearing a bit thinner. Everything would be round and new again. On industrial equipment a "wear sleeve" is sometimes installed when new for this purpose - cut it off and put on a new one at rebuild time. Or, fix a plastic bearing on the rudder shaft, and have it turn in the SS sleeve in the hull. That would probably be good for another 30 years or so. 

Suggest a look at the Jefa webb page: http://www.jefa.com/  they have method and solutions for  non-round shafts. 

Having said that, when I dropped my rudder some few years ago I noticed my shaft was not really round / circular (plastic bearings, ss shaft). I polished a bit, most probably with little or no effect, and re-mounted with a new plastic bearing (non Vesconite, btw, based on some research.). Worked fine, better than I hoped for. 

Agree that 0.001 is not to worry about, can you even measure it? (depends on what unit you are referring to).

//J

 

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I have not checked the shaft for roundness but will.  As said, everyone agreed that it would be unusual for the wear to be on the shaft instead of the bronze bearing.  I'll check it anyway.  

Yes I was thinking a sleeve on the shaft would be an option so thanks for confirming.  I'm guessing that if the OD of the bronze bearing in out of round then that means the stainless sleeve is out of round to.  If the ID of the bronze bearing is out of round, then the shaft may or may not be out of round.  It will be interesting to see what the machine shop finds.

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Remember a hair is about 0.005" and engine bearing tolerances are 0.0005- 0.0015 your talking about a rudder bearing here.  Keep things in perspective.

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I had a similar problem ("clunk, clunk") on my previous boat, and it was due to the top guide bearing wearing. It was aluminum, against a stainless shaft. When measured, it was +0.020" in the fore-aft direction. So from that, 0.020 is enough to cause a clunk. You will need a few thou, maybe 0.003 - 0.005 to get it together. It is possible that the bronze bearing will "close down" a tiny amount when pressed into place as the steel is stiffer, but that shouldn't be more than maybe 0.001. You hope that they potted the SS sleeve in place and accurately in line, otherwise additional clearance is needed for misalignment. The machine shop should be able to estimate the wear, as it will be nearly original dimensions athwartships I would think (that's the way mine was). Then they can duplicate the original. 0.005" sounds small, but in a modern machine shop that's quite a large distance. I don't have the newest machines but they will reliably position to better than 1 micron, which is 0.00004". 

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Thanks for the feedback and perspective.  Yes I have been thinking that I can't get crazy about the tolerances.  However, the machine shop has high end equipment so as long as we're doing it, we may as well get the best fit possible.

I did replace the ball bearings in the top bearing last year so that should be fine.  

I am hoping the machine shop has all the answers regarding dimensions, the bearing swishing down when press fit, roundness, etc.  I'm also hoping that because of the application, the press fit doesn't have to be too tight.  It would be really nice if after freezing, it slid right in :)  This is the one time when I'm really hoping for good shrinkage. 

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If depending on a shrink fit, make sure you have everything ready. From the moment the two pieces contact the stopwatch starts and you have maybe 5 seconds complete it. Half way in is not a good place to be on a shrink fit. You can also heat the ss sleeve to 120 F or more if its a polyester boat and bog. You were able to press it out with a simple tool, I'd go for that again myself. Keeps the heart rate down as you can take your time and scratch your head over problems. 

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Yes babbit is still around I work on evevators and get to redo the bearings a few times a year (as in melt out the old ones and pore new ones)

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I've never commissioned anything to be machined before.  

Aluminum Nickel Bronze = $188 (~3 3/4" OD, 3" long)

Machining = $500

The machining feels a bit steep.  Justified feeling or is that just what it cost?  I pushed a little and they said its very hard so takes longer so it doesn't get too hot.

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2 hours ago, Passport111 said:

I've never commissioned anything to be machined before.  

Aluminum Nickel Bronze = $188 (~3 3/4" OD, 3" long)

Machining = $500

The machining feels a bit steep.  Justified feeling or is that just what it cost?  I pushed a little and they said its very hard so takes longer so it doesn't get too hot.

Dont know your boat...be careful with any dissimilar metals .  

Bronze is a good material

 

The bronze  rudder bearings im familiar with are top bearings, above  waterline..behind lip seals ..and grease packed .

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And machinist fees are generally high ...i just had a pairof small, non technical,  delrin bushings machined...120 per unit 

 

you can save a bit if you supply a correct drawing 

 

if you google bronze bushings you may be able to find a stock size that only needs trim and fit 

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What's their shop rate? $100/hr is 5 hours. That is a lot of machining. Bronze machines much easier than SS. If they have a proper lathe with flood coolant the heat argument is bogus - it isn't going to get hot. I'd have guessed an hour, and I'm usually only off by 2x :). 

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The said $88 per hour.  That is what I thought too.  This is Aluminum Bronze so hard but yes, not as hard as SS.

A gentlemen from the shop visited me at the boat yesterday to take measurements.  Everything was within a couple thousands meaning for all intents and purposes it is round.  He checked the rudder shaft past where the bearing rides and the measurements were the same so no deformation.  

I have to remember that this isn't high speed machinery and that even modern Jeffa plastic bearing are not made to the same tolerance of standard bearings.  

All in all I was relieved that everything was within spec to make it worthwhile to have the new bearing made.  There is definitely visible wear on the inside of the existing bronze bearing so that confirms where things got loose.

The existing needle rollers are a thousandth or 2 smaller than the original 6mm (as far as we know that was the original spec).  I was on the hunt for new ones but guess how that went.  There are hardly any sources for loose needle rollers much less a specific size.  When I was quoted some ( a few hundred or so when I only need 30) I was told they are chromium plated hardened steel which won't do well in water.  So getting stainless is the next problem.

Luckily the machine shop I'm using already does 6mm needles for a customer (SS but not hardened) so they are going to check the hardness of my bearings to see if we can replace them too.

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