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darryl
02-01-2015, 03:47 PM
Was thinking over breakfast today about mechanisms that need to have long lifetimes with little if any maintenance. A project which came to mind is the millennium clock. Any clock in general would be a candidate for a lube that would last and not dry out, even when exposed to air. Just wondering how close our modern products come to delivering this. In particular, I wish to build a 24 hour clock which along with giving an indication of the time, would also be used to control solar panel trackers, etc, and some other functions which might be weekly or seasonal. Of course this means additional reduction gearing etc, but that's not part of the question. There would be ball bearings in this clock as well as plain bearings, and it would be appropriate to use a lube which would still be in place and functional even after decades. I don't expect 10,000 years as with the millennium clock, but surely somethings in that would need to remain lubed and free-working virtually indefinitely. What products might we be able to get that would suit?

Doc Nickel
02-01-2015, 04:39 PM
Any decent synthetic lube should last for a good many years. Often the trick is not that they "dry up", it's that they "run away". The lube slowly drips/oozes/wicks away from where it's needed.

Without heroic efforts or exotic materials, your clock will need at least some attention over the years. The Long Now techs have been working on it for a while, and are using things like jewelled bearings (a hardened steel point in an artifical-sapphire inverted cone, just like a watch but scaled up) and exotic coatings on direct-contact parts (titanium nitride, tungsten nitride, etc.)

Doc.

vincemulhollon
02-01-2015, 05:15 PM
Lubricant contamination too... not so bad if the oil runs out if it experiences super low loads, but really bad if a little dust settles in there. Even worse when water gets in.

From memory of looking this stuff up on bearing mfgr web sites, the ratio of actual loads to rated loads is something like a cube factor of lifetime so doubling the load on a bearing kills the lifetime by a factor of 8, or half load increases lifetime by a factor of 8. So put in the most ridiculous over rated bearings that can be turned and it should last a really long time indeed, although it might be a little hard to turn.

This is all aside from quality, you can buy cheap things that look like bearings from China for wood router bits that have a lifetime measured in minutes, but, sometimes thats all you need, or you can buy $1500 surface grinder bearings that'll run a good fraction of a century.

firbikrhd1
02-01-2015, 05:44 PM
The term lifetime is a bit ambiguous. Are we talking about the lifetime of an end user or the lifetime of a piece of equipment? Personally I'm not a fan of anything reported to have lifetime lubrication. For many people the term lifetime means lasting virtually forever. In the case of tools, some manufacturers give a lifetime guarantee, but try to redeem it when the manufacturer has gone out of business.

I just had to replace both upper and lower ball joints on my vehicle with only 100k miles on it. The original ball joints had no provision for lubrication, i.e. grease fittings. No doubt those ball joints had "lifetime" lubrication. I've owned a number of vehicles over my lifetime (45 years of driving) all with over 100k miles on them, and have never had to replace upper or lower ball joints. Those previous vehicles had grease fittings and got a shot of grease at every oil change.

Is it possible to truly have something with lifetime lubrication? In theory, I suppose so, but even left sitting unused, lubricants dry out and viscosity changes. If there is any possibility of contamination by moisture, humidity or dust that too changes the equation. Regardless of lubricant type, synthetic or conventional, changes take place and contamination and corrosion can and likely will occur. Some lubes may last longer and require fewer replacement cycles but I don't think anything is truly forever.

Personally, if I build something I'd much rather build it with ease of maintenance and lubrication in mind that attempt to build it so lubrication is not required. When it's easy to lubricate it will likely get lubricated, when lubrication is difficult or impossible it won't.

darryl
02-01-2015, 07:02 PM
Yes, the term lifetime is ambiguous. In terms of manufactured mechanical goods, 10 years is often considered a 'life expectancy'. If it lasts 20 years or more, that's often seen as 'luck', or unusual or rare. In this 'newer age' this would be an exception for sure. In earlier years it would just mean that it wasn't built on a friday.

Back when surplus military equipment from the war years was more commonly found, I would see motors and such, still workable as is, even if in need of cleaning and relubing. Sleeve bearings could be found still free to turn, but often with signs of corrosion and drying up lube. Much of this stuff had to be 40+ years old. So what's a lifetime? I'm going to suggest about 30 years. I've seen clocks still running after that time, and there's little chance that they got any oiling at all. If you or I build something and want the bearings to last that long, it shouldn't be a problem. I suppose that synthetic is the best choice here- and it would seem that perhaps there isn't really a product that is designed to outlast that.

lost_cause
02-01-2015, 07:35 PM
i actually bought and started to read the clock of the long now many years ago, but for whatever reason i never finished it. i do remember a discussion in it about that topic and i remember size being a big consideration, meaning that the larger the scale the less of a problem friction was, which would help lessen the lubrication issue.

wern
02-02-2015, 01:08 PM
I have heard of a wristwatch that had a lifetime guaranty, the manufactures
had installed a blade that would slit your wrist just before it stopped working.

Werner

RWO
02-02-2015, 04:03 PM
The horologists are always looking for a long life lube for mechanical clocks. Even the modern synthetic clock oils go away with time. One clock guy I used to know has developed a grease that according to him was the best thing available. He said it would last about 5 years versus standard clock oils that usually last about 2 years.
Maybe the best lube is none at. UHMW polyethylene is very wear resistant and I hear boron nitride coating is very good on steel.

RWO

A.K. Boomer
02-02-2015, 04:21 PM
yes for something totally maintenance free I would not be looking at lube - I would be looking at ceramics...

Bob Fisher
02-02-2015, 05:28 PM
There is an oil, supposedly long lasting called "Nano Oil",which , again, supposedly has spherical nano sized diamonds thatact as ball bearings. It is widely known in horological and firearm circles. I have used it with some success on one clock. Only time will tell on this one. It is pricey however, tiny little bottle about the size of your pinky first joint for about $35. Bob.

A.K. Boomer
02-02-2015, 05:31 PM
that's interesting but sounds if pushed could get abrasive ?


how do you get it to stick?

im thinking of graphite just blowing in the breeze...

A.K. Boomer
02-02-2015, 06:43 PM
I guess it's kinda like how moly spray works - they use a carrier lube that dries pretty quick and leaves the "nano's" behind....

if the testings for real is would be amazing,,, iv seen these tests with BG MOA in comparison to things like castrol or mobil 1

the thing about these test is that if there's no real detectable wear it means the unit pressure is off the charts as the contact area remains next to nothing,,, even the BG showed a small rut --- I can't seem to get a good view but I can't detect anything off to the right? it's for that reason that I do have to ask if this is being realistic... not crying foul ball - just saying caution...

http://www.diamondlube.com/NanoLube.html