lower rudder needle bearing fabrication?

kassita

kassita

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Hello all,

Can anyone suggest someone to fabricate a replacement for the pictured lower rudder needle bearing, taken off my Humphreys custom 36?

It runs on an 80 mm nominal diameter stock, in a 107 mm internal diameter rudder tube. I can give whoever does the work precise measurements.

We are based in Cowes, so IOW based would be a bonus.

8594073459_b42460a579.jpg



Many thanks!
Kass
 
kassita said:
Hello all,

Can anyone suggest someone to fabricate a replacement for the pictured lower rudder needle bearing, taken off my Humphreys custom 36?

It runs on an 80 mm nominal diameter stock, in a 107 mm internal diameter rudder tube. I can give whoever does the work precise measurements.

We are based in Cowes, so IOW based would be a bonus.

8594073459_b42460a579.jpg



Many thanks!
Kass
Click to expand...
You need access to a toolroom to fabricate this so look for any Toolmakers / Precision Engineers in IOW, (yellow pages) take it along to them and negotiate a price.
 
kassita said:
Hello all,

Can anyone suggest someone to fabricate a replacement for the pictured lower rudder needle bearing, taken off my Humphreys custom 36?

It runs on an 80 mm nominal diameter stock, in a 107 mm internal diameter rudder tube. I can give whoever does the work precise measurements.

We are based in Cowes, so IOW based would be a bonus.

8594073459_b42460a579.jpg



Many thanks!
Kass
Click to expand...
You could try http://jefa.com/rudder.htm this company deliver rudder and steering systems to a lot of production boats.
Very helfull when I contacted them.
 
Last edited:
What is the problem? If it is just worn rollers, then any competent engineer should be able to replace them and the pins they run on, whilst retaining the existing cage, which is the hardest part to make. I very much doubt that the bearing is a one off, so a visit to a bearing supply house (look in Yellow Pages) may reveal an off the shelf replacement which is likely to be much cheaper than the fiddly job of replacing the rollers. If the problem is wear on the rudder stock or a damaged outer race, no replacement of the rollers will solve the problem.
 
You could replace it with a low friction plane bush, I guess the shaft is SS and it will run dry? Just need to know the carrier material and sizes.
 
Norman_E said:
What is the problem? If it is just worn rollers, then any competent engineer should be able to replace them and the pins they run on, whilst retaining the existing cage, which is the hardest part to make. I very much doubt that the bearing is a one off, so a visit to a bearing supply house (look in Yellow Pages) may reveal an off the shelf replacement which is likely to be much cheaper than the fiddly job of replacing the rollers. If the problem is wear on the rudder stock or a damaged outer race, no replacement of the rollers will solve the problem.
Click to expand...

The bearing is a one-off, originally made by NeedleSpar, who no longer do this sort of work. The problem is indeed worn rollers. I have contacted a toolmaker in Freshwater, so I'll see what they can do and for how much. If they can just replace the rollers that would be ideal.

We are already looking at Jefa as a plan B, but that is likely to take longer.

Many thanks,
Kass
 
kassita said:
The bearing is a one-off, originally made by NeedleSpar, who no longer do this sort of work. The problem is indeed worn rollers. I have contacted a toolmaker in Freshwater, so I'll see what they can do and for how much. If they can just replace the rollers that would be ideal.

We are already looking at Jefa as a plan B, but that is likely to take longer.

Many thanks,
Kass
Click to expand...
I think Jefa is stocking some of the bearings - worth a try.
 
Does a rudder really need a roller bearing? I would have thought a plain nylon, or similar, bearing would do just as well.
 
NormanS said:
Does a rudder really need a roller bearing? I would have thought a plain nylon, or similar, bearing would do just as well.
Click to expand...
No, as I suggested some of the modern materials combine high strength (don't deform under pressure) with very low dry friction properties as well as low moisture and thermal swell.

"Not nylon as it swells a lot when it gets wet - acetal or delrin are much better"
True delrin is better than nylon, but it still has a relatively (to new materials) high moisture and thermal swell, it also deforms under pressure as well as melting/getting softer as it gets warmer.

superheat6k said:
Try Beldam Crossley in Bolton and ask for their Rulon material this is a formed PTFE product.
Click to expand...

Being PTFE based it will not be good for rollers or as a plain bush under higher loads, ptfe is a soft material and won't withstand higher pressure loads without deforming.

The most recent materials (recently tested in rudder simulations) show lower friction than teflon (MoS2 and or Graphite in resin matrix) great mechanical strength and low thermal and moisture swell rates. These are suitable for replacing rollers in this type of application. We use one of these grades on submarine dive planes which required low noise/close tolerance and no stiction under immense pressure loads with a wide operating temperature range.
 
Hole gets smaller, if the bearing expands more than the material in the carrier as it is thus restricted in its outward growth. It has the same effect as pushing a bearing into a carrier (interference fit as most shaft bearings are) the ID will be reduced as the bearing is squeezed.

Hence it's important to know the material of the shaft and carrier as this effects the required clearances and also the temperature range that the materials will see. Recent developments have been to get the thermal expansions reduced, with low porosity, dense, mechanically strong structures.
 
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