Propeller nut/spinner

Graham_Wright said:
I've just been quoted £50 for phosphor bronze M30 nut!

I can't find any suppliers on the net. Any help please?
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Have you tried Anglia Stainless Ltd (despite the name they sell bronze fastenings)?

Does it have to be phosphor bronze, by the way? Silicon bronze is the normal type used for marine fastenings
 
Rogershaw said:
If your prop shaft is stainless why not use stainless ? Mine is stainless and no ill effects on my bronze prop
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I have a fear of stainless on stainless galling. From time to time we produce items for a chicken processing factory and on one occasion it took an hour to free a M50 X 1mm nut from a shaft we had produced.

I have also had SS nuts seize on my chainplate fixings.

I have been told that mixi9ng grades can remove this effect but the shaft is 316 and I don't fancy 303 or 304 nuts.
 
When I fitted out my previous boat I would get galling a lot and found it mainly happened when I got the cement dust on the bolt thread before fixing. Once I started to ensure the threads were clean the problem went away.

During the building of my current steel boat I again used a lot of stainless, in fact the only bronze fittings are my prop and bow thruster leg, I insisted on all stainless to stainless threads had some kind of grease applied before fitting and the only time we got galling was when my staff forgot to apply the grease.

My prop nut has a left hand thread and is locked to the shaft with a right hand threaded screw fitted in a tapped hole in the end of the shaft all fitted with underwater grease.

Two month ago my diver removed my prop with the boat still in the water with no problem this was so I could replace the prop with a re-pitched stainless prop I am currently fabricating size being 20" dia by 14" pitch.
 
sarabande said:
worth a call here ?

http://www.jameshealy.ie/docs/JHL Catalogue V3.pdf


Or Woods of Crediton ?

http://www.woods-group.co.uk/


And these people seem to know what is what.

http://www.ondrives.com/about/index.php


And you never know, they might have something in stock.

http://www.abssac.co.uk/s/Lead+screws+Power+Range/1/2/
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Nope to all those and the last one produces leadscrews so the "nuts" are not what we would call nuts. (They are round and high precision).

I'll make my own. Do I design it as a spinner or do I use a nut with a spinner made from zinc?

Lifes too difficult!
 
I made an odd UNEF nut for a forumite I few months ago. I charged him 15 quid as it was material I had in. For one of these I reckon I could make one for about 20 quid.

Here's the one I made earlier.
 
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The brass nut shown on my website as an example of dezincification was almost 20 years old when it was removed. I would probably have carried on using it if it had fitted the new prop. I guess you could buy three or four in brass for a lot less than £50, keep the others for spares. Might last 100 years.

Incidentally, any grade of 300 series stainless will gall on another. It is common to put A2 nuts on A4 bolts, this combination galls just as well as if they had both been A4. Yesterday i was looking at a rod-rigged boat that had very interesting turnbuckles. The threaded section was teflon coated in manufacture to help resist galling. Molybdenum disulphide grease is perhaps a better solution but very messy.
 
vyv_cox said:
The brass nut shown on my website as an example of dezincification was almost 20 years old when it was removed. I would probably have carried on using it if it had fitted the new prop. I guess you could buy three or four in brass for a lot less than £50, keep the others for spares. Might last 100 years.

Incidentally, any grade of 300 series stainless will gall on another. It is common to put A2 nuts on A4 bolts, this combination galls just as well as if they had both been A4. Yesterday i was looking at a rod-rigged boat that had very interesting turnbuckles. The threaded section was teflon coated in manufacture to help resist galling. Molybdenum disulphide grease is perhaps a better solution but very messy.
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Some years ago, my company bought in a full bar of Ø50 aluminium bronze for a job that went away. I believe the cost then was over £400! Apart from one of my staff cutting off a short length for a job mistaking it for brass, it lies intact.

I believe it is superior to phoshor bronze for strength and corrosion resistance so, subject to Vyv's advice, I will knock out a couple from that.
The jury is still out on whether to make a nut or a spinner or to make a nut and add a zinc spinner. There is insufficient room before the prop to insert a shaft anode of any useful length (unless I shorten the cutlass bearing housing which seems a bad idea).
 
Aluminium bronze would be a very good choice. I happen to know that the bearings for the Thames barrier gates are made in that material, with polymer inserts. Propellers are made from it and it surprises me that it isnot more widely used. Maybe the cost of your piece is the answer!
 
I think you've already answered your own question as you have the expertise and materials to make your own. I would be inclined to go for a standard nut, possibly castellated for locking with a separate spinner cone in zinc. In my own installation, the nut came with the new prop and there is a large hull anode nearby.

Rob.
 
rob2 said:
I think you've already answered your own question as you have the expertise and materials to make your own. I would be inclined to go for a standard nut, possibly castellated for locking with a separate spinner cone in zinc. In my own installation, the nut came with the new prop and there is a large hull anode nearby.

Rob.
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I visited the Seawork exhibition yesterday and spoke to MG Duff the anode people. They do nuts and screw on zinc spinners. Just what I was looking for.

But;- M24, M28 and M32. I want M30!

Back to the Ali bronze!
 
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