leftover gear oil uses?

[jon hill 3Participant @jonhill3]

Getting round to my van servicing to do list I bought some gl4 75-80  Smith & Allen gear oil.  After exchanging fluid on the gearbox and rear differential I still have a few litres left over. So rather than have it hanging around could I use it as lathe ways oil?

[Howard LewisParticipant @howardlewis46836]

It will certainly prevent condensation on the surface. Being fairly viscous, a little will go a long way, given enough time, or if spread by hand or paint brush.

I would be tempted to fill an oil can and use to lubricate the gear wheels, once the meshing has been set, (Run a sheet of 80 grm copy paper through each mesh, starting with Leadscrew / Idler, then swing the banjo to set the Idler/Driver backlash in the same way)

But be careful with Hypoid and EP oils which contain sulphur, which can, long term attack brass  or bronze bushes.

Howard

[Nick WheelerParticipant @nickwheeler]

You could spread it over the ways but will you be able to live with the smell? And why did you buy so much that you have litres left over?

[jon hill 3Participant @jonhill3]

Thanks for the advice Howard, having looked it up it is EP oil.  I dont think I have any brass gears on my myford speed 10 but could it have a corrosive with the aluminium half nut?

 

I bought 5 litres of this oil as it worked out a better deal then smaller packs of other brand gear oil and the brand is an established English manufacturer too.

[SillyOldDufferModerator @sillyoldduffer]

Using gear oil on the ways won’t do much harm, and might do some good.

Lubricants are engineered to be at their best in particular circumstances, and it’s best to use the right one when it matters.  Examples:

• Car engine oils where viscosity and stickiness increases with temperature.   The starter motor and battery don’t have to fight a thick oil.   However, when the engine is running the oil should thicken to protect the bearings.   The oil is also designed to resist heat – it’s part of the cooling system.
• Although Gear Oils run cooler than engine oils, they are badly stressed by mechanical squeezing between gears.  Therefore, viscosity is fixed, not heat resistant, but the chemistry is adjusted to keep the oil slippery through-life, even though the molecules are being mangled.    Gear oil can be toughened with Sulphur (chemical reaction, not adding a spoonful!), but this type of oil slowly corrodes Copper.  Don’t use it with Brass or Bronze.  As far as I know other metals aren’t attacked by it. Read the label!
• Steam Oils are formulated to resist hydrolysis and emulsioning.   High-pressure, high temperature steam destroys ordinary oils by cooking them,.
• Penetrating oils are deliberately thin and usually contain chemicals that attack corrosion.   Not sticky, heat resistant, or low viscosity and no-one cares if the molecules are mangled.
• Household oils like 3-in-1 are formulated to suit domestic requirements, like hinges and locks.  The oil is low toxicity, and and doesn’t corrode or smell.  Not a disaster if spilled!    The oil has useful middle of road properties: it penetrates mildly well, cleans grease moderately well, and is sticky and viscous enough to stop hinges squeaking.   On the downside, it contains an organic oil that slowly gums up by oxidising.   Don’t use Household Oil on light or hot mechanisms.
• A book could be written about the pros and cons of WD40!
• Clock oil is very thin for use in very light mechanisms, and formulated not to oxidise or corrode.  Don’t substitute anything else!
• Sewing machine oil is similar to clock oil but thicker to suit heavier mechanisms.
• Cutting oils resist high pressure and absorb heat.  Low viscosity for Aluminium, higher for Steel.  Heat absorption doesn’t matter when tap / die cutting threads,  it might when rolling or single point cutting them.
• Way Oil is extra sticky and resists being scraped off the slide.
• And many other examples!

Lathes, especially hobby machines, aren’t fussy.   Compared with other mechanisms they don’t get hot, their gears are lightly stressed, and they are more robust than most. The slides aren’t heavily loaded.  Thus almost any oil splashed on a lathe will be harmless, or mildly beneficial .  Exceptions:

• The machine is doing heavy production work.  Needs all the help it can get, don’t scrimp.
• Plain bearings are often total loss lubricated.  Clean oil flows from a reservoir through the bearing and out the other side,  lubricating and washing out dirt and metal scrapings as it goes.   Important to maintain the flow by using the recommended thinnish oil, and not blocking the outlet.   Don’t fix leaky bearings with a heavy oil, grease, or o-rings!  The bearing is probably making an oily mess because it’s worn.
• Don’t use EP Gear Oils containing Sulphur on anything containing Copper, ad don’t forget out-of-sight half-nuts and bushes.
• Try to keep a substitute oil’s viscosity similar to that recommended by lathe maker, not wildly different.

The sky won’t fall in if gear oil is used as a Way Oil, but it won’t be as effective.  When slides are moved, they tend to push oil out. Proper way oil is formulate to resist being squeegeed, gear oil isn’t.   May not matter in a home workshop because most hobby machines aren’t worked continuously.   On the other hand, lightly used lathes are prone to rust, in which case an application of gear oil at close of play will help.

Dave

 

 

 

[halfnutParticipant @halfnut]

The stuff stinks. Don’t use it on your lathe. It’s viscosity is about the same as engine oil. They just use two different numbering systems so people don’t put gear oil in their engine or vice versa.

There is more misinformation about oil on the net than almost anything else, so beware of armchair expert advice. Just stick with manufacturers recommendations.

That said, save a lot of mess on your change gears and use modern clear Teflon motorcycle chain spray. It sticks to the gears but swarf does not stick to it. No fling, no mess.

 

 

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