Metal to metal dry lubrication... what product?

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davidUK

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

Screenshot 2022-10-01 at 17.04.33.png

Screenshot 2022-10-01 at 17.04.45.png


Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
 

Brian Rupnow

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Try using paste style floor wax. Sometimes it works good to give a smooth sliding surface with very little "stiction".
 

GailInNM

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davidUK

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Brian,
I have used Dupont Non-Stick dry film lube for many years where I needed those qualities.


I get mine from the local home improvement store, but the Amazon link was included to show you what it looks like.
Gail
Can't find that in the UK, but it puts me on the right track perhaps. Thanks.
 

HMEL

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

View attachment 140322
View attachment 140323

Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
I have worked with air compressors whose cylinder walls were embedded with Teflon. This was a special treatment for the pistons which ran dry. I cant help with how to do it because it was applied at the factory and then polished into the wall. There are some special applications of the stuff that are applied wet like a paint and allowed to dry.

But just for experimenting I would start with something very simple like graphite powder. I used this on the axles for young scouts that raced the pinewood derby cars and at one time graphite was used on bearing mounts for gyroscopes. The graphite works as long as its not working at low or no air pressure. The success of graphite will depend on how moist your environment is.

Good luck with your search.
 

terryd

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

View attachment 140322
View attachment 140323

Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
Hi David,

You could always try a PTFE lubricant such as that sold as a dry lubricant for bicycle and motorbike chains. It goes on wet then the carrier evaporates leaving a dry film. NASA use similar lubricants. I use it on my Machine tool applications such as sludeways and it not only lubricates but it keeps the dreaded rust at bay. It's not too expensive and available at bike shops or Amazon (I get mine from there). I have tried several manufacturers products, E.g. WD40, 3-in-1 etc all do PTFE sprays here's the one I'm using at the moment, it not a spray, it goes on 'wet' but quickly dries to a long lasting film. You don't need much and it goes a long way and has many other uses- I use it on my bike chain (obviosly), car door hinges and locks (dry so it doesn't mark clothes etc. The film is very tough hence the use in a very difficult application such as a bike chain .

Of course there are also the white dry lithium lubricants by such as 3-in-1, it is 'dry' and tends to leave a thicker coating which may work better, but you will need to experiment: See Here. Again used for door hinges,locks etc hard wearing and lasting.



1664770922662.png 1664771001545.png

Best regards

TerryD
 

Richard Hed

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

View attachment 140322
View attachment 140323

Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
Would it be possible to polish the object then have it chromed? Also, you might be able to use silicon or lithium base or non oil based grease.
 

terryd

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

View attachment 140322
View attachment 140323

Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
Hi David,
second thought - how about 'tinning' the head of the bolt with electrical grade solder which is quite hard depending on the final application the mechanism is intended for, or even easy grade silver solder which could be polished and very hard wearing? There is also 'encapsulating resin' sold in hobby stores or even a thin epoxy resin coating using the slow setting stuff will allow the resin time to spreas a thi even coating, Again the y could be polished to ensure no frictionas you describe, Fine grades of wet and dry used wet when set will do the job of polishing perhaps finishing with the ubiquitous T-Cut or Brasso.
All coatings will still allow the magnet link to work. I take Richard's point about chromium plating but that could be quite expensive as a one off as the plater will insist on polishing to his standards so that there is no 'come back' if there are problems later. however it is a viable process, but my suggestions are more 'home brewed' and the bolts are cheap so it's worth experimenting. Let us know how you get on.

Regards

TerryD
 
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terryd

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I'm working on a small mechanism which uses a strong neodymium countersunk magnet and a socket headed button screw as its base which allows swivelling and height adjustment (via the thread).

The BZP M3 screw has a fairly smooth head which fits into the less than smooth countersink of the triple nickel plated magnet, as under. This forms a "ball and socket" arrangement...

View attachment 140322
View attachment 140323

Due to the rough surface/s, very small movements are resisted as the surfaces lock together microscopically.
I need to adjust the mechanism minutely.

The mechanism will work in a moist environment.
I can't polish the countersink as this would be difficult due to the nickel's hardness, and if I break through it the neodymium under is very prone to rusting and then crumbling.
The magnets are made in China and I'm unlikely to be able to get the manufacturer to amend the design to provide a polished countersink.

I'd like to lubricate the mating surfaces to ease movement.
I don't want to use an oil or anything "wet".
What dry lube might be the best to try? Something long-lasting, dust and dirt resistant, moisture resistant.

Many thanks for any suggestions.
Hi David,
Yet another thought - how about coating both components with say epoxy, which sets very hard, using a disposable paintbrush to get an even coating, let it spread smoothly and evenly and when hard, use a lithium or PTFE dry lubrication. Personally I'm not keen on silicone my experience is that it tends to get sticky unless used in higher speed situations than the one you are proposing, others may have had diferent experiences of course.

TerryD
 

davidUK

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I've seen heat cured moly which can be applied and cured in an oven, but I've no idea yet if it's available in small quantities for DIY. I'll speak to a few slippery specialists later today and see what they say. I've used silicone for seals before and it does stick, especially when moist.
 

davidyat

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You might want to look for Powdered Graphite. I've used in key locks. It's just like ground up pencil lead.
Grasshopper

 

davidUK

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Thanks David. How much would powdered graphite spread around and make a mess?
Does it bond with the metal or would it disappear over time>

I was looking at white lithium grease yesterday until I found it's likely to attract dust and dirt...
 

davidyat

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Well, probably a mess when you apply it. Just imagine taking the lead out of a pencil and going over to a grinder. Shove the lead into the grinder and you have graphite dust. About the same. It looks like you only need the dust between the screw and the magnet. I'm guessing the combination isn't moving all that much. Not sure of the bonding characteristics. Hope this helps.
Grasshopper
 

Steve J

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Molybendum Disulphite. my not be the right spelling but it works. its like a silvery dry powder
 

davidUK

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Molybendum Disulphite. my not be the right spelling but it works. its like a silvery dry powder
I was Googling earlier and phoned Moly slip. Their technical chap Sam (Slippery Sam?) phoned back and suggested their Dry Moly Spray: DRY MOLY SPRAY - Molyslip

After I explained my patent pending invention he offered to drop in with a complimentary can. He lives not far from me.

What a good chap!
 

Rod N

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I wish Slippery Sam lived near me in Brisbane!!! The dry Moly Spray looks good especially free!! Also dry PTFE (Teflon) spray suggested earlier would be my choice, assuming there are no high temps (above 200degC) involved.
 

davidUK

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My suggestion is to place a thin piece of UHMW tape with double sided adhesive over the magnet, apply a bit of heat, clamp with a shaped surface, then trim when cool.
I had thought if gluing some kind of half shell bearing into the magnet with the same radius as the screw head, but I'd never find one that's perfect. I've just looked up the tape you mention and it looks a possible "proper fix". When you say "a bit of heat" what are we talking... hair dryer heat?

The Moly slip dry lube has arrived. I sprayed both components and left to dry for an hour. When together the grey sprayed area of contact immediately gets rubbed away leaving metal on metal again. Am I missing something? It doesn't say how long to leave it to dry, maybe it needs longer? Maybe the film is invisible and I'm being led by the grey disappearing?

@terryd - found I had the same Finish Line bike lube in the garage so I'm trying that too.
 
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