Machining oil impregnated bronze

Don't run a turned part too fast or you will sling oil out of it. Start slow and increase speed until you see an oil film on the surface of the part. Don't go faster.

If you have a part needs re-oiling, use plain SAE 30 non-detergent oil. If you put the part in a jar (I use a Mason jar), cover with oil and then pull a vacuum on it, it will re-impregnate.

Randy

I've been collecting opinions on this subject for years, so don't mistake why I'm asking this. I'm just looking for an answer: but why non-detergent oil for a total-loss bearing, such as an Oilite?

Ed Huntress

Detergent oil in an environment that has no water is worthless (or worse). In an engine, where combustion puts substantial amounts of water vapor in contact with the oil on a regular basis, it helps clean things, but in a "dry" environment like a sleeve, bushing, or similar sort of bearing, where water isn't available, the detergent can and will gum things up as it desperately tries to find someplace to stick its hydrophilic (water loving) end, and ends up grabbing at pretty much anything that resembles moisture. Since there isn't enough moisture to flush away the resulting mix (for a good real-life example, try washing your hair with straight shampoo - NO WATER ALLOWED! - and see how well it works.)

Odd but I've run detergent oil in my lathe headstock bearings (south bends of various sorts) and have never seen any gumming or sticking problems.

Jim

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but why non-detergent

I believe detergents in oil, (motor oil) are there to clean and suspend the products of combustion. Detergents would do no good in plain bearings. They couldn't clean abrasive particles from the bearing - in fact if that were possible it would tend to degrade the imbedability characteristic of the softer side.

Bob Swinney

All I can give is my personal experience, in a limited range of machines - and that is that detergent oil seems to do no harm - over a span of about ten years or so, to be specific.

I don't think so. The API certification does not seem to be applicable to non-detergent oil. My wife picked up a quart of store brand oil at the local supermarket, and it was indeed non-detergent, and did not carry the API mark.

Jim

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Well, that tells us the type and weight they recommend, but not anything about detergents -- unless I missed it?

Ed Huntress

the very top of the page: mineral oil (to ISO VG(SAE 30)), which is highly viscous and contains anti-foaming, anti-rust and anti-oxidising agents.

afaik, any "detergents" are added to motor oil to extend it's life by keeping contaminents from completely reacting and in suspension.

a 100% systh oil does not use them, many don't use any additive. that should tell the story, you are treating the oil, not the engine. that's just my amateur ho. --Loren

If you have a part needs re-oiling, use plain SAE 30 non-detergent oil.

Turbine oil is the recommended lubricant.

Get it at ACE for about $1.98 for a Zoom Spout container.

I'm surprised at that. The "turbine" oil I have seems very light compared to what oozes out when I machine oilite. Where did you get that info? TIA

Ted

....

I wonder if it was your distaste for chemistry which got to him.

But I have encountered a good explanation of what detergents do in situations like this. It is targeted at laymen, but it's a real explanation, not an oversimplified horror. It occupies a chapter or two (perhaps 30 or 50 pages) of Harold McGee's book "On Food and Cooking" -- the chapter on oil/water emulsions, as applied to the making of sauces such as mayonnaise. Basically, if you want water and oil to mix, you have to do so mechanically (beating them), and if you want them to stay mixed, you have to add detergents. The mere presence of detergents won't cause mixing; it will only stabilize a mix. McGee explains what all the little detergent molecules do, to produce this effect. Actually "detergent" isn't quite the right word here; "emulsifying agent" would be better. Detergents are one type of emulsifying agent, but there are others, like the ones McGee talks about from egg yolks.

It's the same basic chemistry, and it won't evoke dark thoughts about Halliburton on every page you read. :-)

Hey, it isn't distaste. It's simple ignorance.

I'll take your word for it. I have to tell you, though, although it may be superstition on my part, I don't make meals from cookbooks that show diagrams of hydrocarbons.

Ed Huntress, CCI (Certified Chemistry Ignoramus)

Oh, that isn't the sort of book that says to bake buns with rancid butter at maximum heat, rather than fresh butter at moderate heat, because it makes the Maillard reaction go better. Nor does the book try to make you remember the difference between linolenic acid and linoleic acid. It's easy reading -- easier reading than what I wrote above.