Which lube to use?

[stevehertz]

Originally Posted by ajgriff

Very much agree with Craig's comments regarding silicones. In a domestic setting I still have an early LCD TV with manual operating buttons which only work intermittently. This was caused by general purpose spray polish containing silicones. The offending sprayer refused to heed my pleas not to use the stuff on electronic equipment. Aside from creep and the difficulty associated with removal, certain formulations of silicone create an electrically resistive barrier. Despite trying every trick in the book I've never managed to completely clean these switch contacts. However, the remote still works so the set acts as a useful spare.

First came across this issue in a corporate environment when PCs were first installed on every desk. For a while nobody could explain the high rate of keyboard and switch failures until it was discovered that the office cleaning staff were using silicone based aerosols. Subsequently all cleaning contracts were written with clauses banning the use of cleansing agents containing silicones.

Alan

All very well and true but if a vintage wireless enthusiast sprayed silicon polish onto a switch then the results are what they deserve for being so stupid. It's a bit like saying my five year old daughter washed the DAB radio in a bowl full of crocks and washing up as an example that it's not a wise thing to do, to immerse battery radios in bowls full of washing up liquid - obviously it isn't. Like I said, precision, local application of a droplet of lube onto a tuning cord roller bearing or the like creates no problems, it's very effective and long lasting. I also lightly prime and buff the surface of the 'track' on which the tuning pointer traverses. Together, these procedures facilitate very effective 'spin' of the tuning pointer from end to end. I'm not suggesting a willy nilly approach to using ANY lube, but an intelligent, very effective one that won't damage paint finishes, plastics or rubber and has no negatives.

[ajgriff]

Returning to the original question, does anyone have any idea as to the type of lubricant actually used by Technics? The service manual for the SL-3 doesn't seem to offer any clues.

Alan

[McMurdo]

if it's anything like the stuff on CD sled rails, it's Molykote, which is a white lithium-in-silicone grease. The datasheet lists its applications as including 'aircraft engines'.

[Bazz4CQJ]

Molykote is a brand name of Dow, but it covers a very wide range of individual products, so we need to specify something like 'Molykote XYZ'.

Re silicones, a few years ago I had a work colleague who told me that in her previous job (electronics) they had a separate admin building and silicone products (polishes) were banned in there. She didn't say whether or not it was an issue specific to PC's, I just assumed it was a site-wide ban.

I stumbled upon another forum recently where the members were having a "frank and lively" discussion about various brands/types of lubricants - in this instance about the lubricants used in the valves of trumpets! One comment that was made that struck me was that in some tests, some favoured products (oils) were found to evaporate to "apparent dryness" within a few days. Of course, that does exclude the possibility that just a thin molecular layer was left behind with really good lubrication properties!

B

[Craig Sawyers]

Slightly OT, but I used to lube the mechanism of my clarinet with plain old 3 in 1.

And on-topic, recently a friend's CD transport (an old Meridian) drawer was operating erratically. So I cleaned the sled rails and re-lubed with sewing machine oil (see earlier). Problem solved.

[thomash93]

Thanks for all the advice.

Sounds like sewing machine oil is a tried and tested non controversial product?

Something like this?
https://www.prym.com/en/sewing-machine-oil-20ml-611998

Saying this the tone arm sled seems to have been greased rather than oiled. Will the oil be too thin?

The various threads I've read recommend using various lubes, greases and oils but it seems to be heavily dependant on personal preference rather than there being hard rules about composition and viscosity. For a beginner who want's to do it right it's difficult to know what to use!

[ajgriff]

I heartily sympathise. It is also difficult to establish the actual constituents used in the multitude of available lubricants. Have to say that I now tend to take a very simplistic approach and think of thin oils in terms of slipperiness and thicker greases for longevity.

I'll probably be shot down in flames for saying so but I think engine multigrade is a great compromise in very many circumstances. Synthetic or mineral anyone!?

Alan

[emeritus]

The lubricants specified by the official Philips service manual for my late 1970's cassette deck were W20/50 engine oil for the axles of gears and an ordinary Lithium wheel bearing grease for sliding surfaces and metal gear teeth.

[Craig Sawyers]

Originally Posted by ajgriff

I heartily sympathise. It is also difficult to establish the actual constituents used in the multitude of available lubricants. Have to say that I now tend to take a very simplistic approach and think of thin oils in terms of slipperiness and thicker greases for longevity.

I'll probably be shot down in flames for saying so but I think engine multigrade is a great compromise in very many circumstances. Synthetic or mineral anyone!?

Alan

I use single weight detergent-free classic engine oil (Comma) for the main bearing of my Garrard 401, and sewing machine oil for the motor bearings.

[Dual Standard]

Originally Posted by McMurdo

if it's anything like the stuff on CD sled rails, it's Molykote, which is a white lithium-in-silicone grease.

I have no knowledge of the Technics SL-3 but the white grease I have seen on CD sled rails looks and feels just like Molykote 33. This is described as 'compatible with many plastics', indeed it is widely used on plastic to metal (& metal to metal) surfaces in ATMs without causing a problem.
Looks like it is readily available in 100g tubes at less than ridiculous prices.

Mike

[Craig Sawyers]

Lithium soap thickened silicone oil. They say the benefit is that it operates over a wider temperature range as compared with a mineral grease. so -73C to 204C rather than -30C to 170C for mineral.

I'm just going to leave it at that

[Synchrodyne]

As already said, the best starting point is to ascertain what lubricant the equipment manufacturer used in the first place and/or specified in the service manual. It is reasonable to assume that there was adequate diligence behind that selection, and that as well as doing the primary job, it did not have unwanted side effects. The manufacturer generally does not want warranty returns or loss of reputation because of poor selection of a component – really a consumable in this case.

Failing that, then consider the application. In this case we have a very low speed sliding mechanism that is subject to controlled speed variations as an operational requirement, if not actual stop-start, and which requires precision positioning. The driving power is probably very limited, as well. Very low friction is indicated, but more than that, a static friction coefficient that is lower than the dynamic friction coefficient is required to ensure that there is no chance of even incipient stick-slip. The mechanism is probably somewhat open to atmosphere, so whatever is chosen should be non-attractive to airborne particulates that might adhere to the slide rails with progressively deleterious effect. That points to PTFE as being a suitable candidate. I’d say that there was a good chance that that was what Technics used, but it would be better if we had confirmation on that point.

The CD drawer slide-rail case is a much easier proposition. The sliding motion, once started, is continuous; some variation in sliding speed over the course of travel is not an operational problem, although it may be aesthetically undesirable. There is no precise intermediate positioning requirement involved; the end-stops essentially take care of what is needed. Probably enough driving power can be provided to overcome starting friction and any in-service build-up of dynamic friction due to the progressive deposition of airborne contaminants. Anti-stick slip properties are nice to have but not essential.

More generally, the lubricants world, at the consumer level at least, is as full of myths, misunderstandings, misconceptions and bad science as is the audio world. It pays to be wary of what one may find on the internet.


Cheers,