Chain bar oil <--> used 75W90 transmission oil?

I just changed my transmission of 75W90 GL-4 (low sulfur) spec.

What do you think of using it as bar oil for my Husky chain saw?

Anyone done it?

The advantage is obvious. What's the drawback (don't guess because I can guess too).

I'm asking if anyone has ever used used gear oil for chain lube and lived to tell the story about how it worked out?

Reply to
Chaya Eve
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On Tue, 19 Sep 2017 18:57:18 +0000 (UTC), Chaya Eve wrote in

I've used 90w gear oil new from the bottle. I would be hesitant to use _used_ oil from anywhere because it might contain particles that could clog the chain oil delivery system.

Reply to
CRNG

Thanks for letting me know that 90 weight gear oil can work, if new from the bottle. The Red Line MT-90 is about 20 bucks a quart so I wouldn't use that.

I understand your point about the particles, which definitely were in the magnetic trap. I guess I could "filter" out the bigger particles, but your point is valid that almost certainly there are myriad small particles in used gear oil.

I think your suggestion that the particles would be bad for the chain is a good enough reason to just throw the used oil out (to Jiffy Lube) and waste it.

Reply to
Chaya Eve

I would just recycle the used petroleum gear oil. I have three Stihl chainsaws, a 14", 20" and 36" monster. For the past decade, we have been using soybean cooking oil for the bars and chains. Works great and is environmentally safe.

Reply to
Stormin' Norman

I don't know about TF or gear oil but over the years, I accumulated about a dozen partially used containers of various weight and age non-synthetic engine oil- 30, 40, 10-30, 5-20, 10-40, etc. which were left over from oil changes and top-ups on vehicles and power equipment I no longer own.

They've all worked fine as bar oil in large and small chainsaws, including one electric.

Reply to
Wade Garrett

It's much heavier than bar lube oils that are more in the SAE 30 weight range.

I've used recycled SF SAE 5-40 from the tractors as bar oil for years with no discernible ill effects...then again, I'm not a professional tree trimmer or woodcutter, either, so they get intermittent use, not continual.

Reply to
dpb

I'm not sure if it's actually "much heavier" and it might actually be the same viscosity.

I think, they use a different viscosity standard for gear oils than for the viscosity of motor oils as shown in this chart.

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This says that they are the same viscosity:

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"While many motorists may assume SAE 90 gear oil is thicker than SAE 40 or

50 motor oil, they are actually the same viscosity; the difference is in the additives."

Wiki says the same thing

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"API viscosity ratings for gear oils are not directly comparable with those for motor oil, and they are thinner[further explanation needed] than the figures suggest.[by whom?] For example, many[quantify] modern gearboxes use a 75W90 gear oil, which is actually of equivalent viscosity to a 10W40 motor oil."

If that's correct, the SAE 75W90 is the same as a 10W40 in cold viscosity, which is to say a 90 weight gear oil is the same as a 40 weight motor oil at elevated temperature (or a 75W is the same as a 10W at cold temperature).

I'm not sure which weight matters in a chain saw whose oil is probably midway in temperature (at ambient temperature) between the cold temperature and hot temperature rating of oils.

Reply to
Chaya Eve

I can't speak for chainsaws but I use 90W gear oil on both my chain drive motorcycles and get as good a chain life as some of the fancy spray products.

I don't know about the used oil part. The generic stuff I buy is about $10 a quart and lasts a long time.

Reply to
rbowman

I normally use Lowes sticky chain lube bought by the gallon but now I have a gallon of used 75W90 so I was just wondering ...

It must have metal flakes in it though, so it might not be worth it if it screws up the chainsaw. I'm not so worried about the $30 chain but more about the $350 chainsaw.

Reply to
Chaya Eve

I only have 3/10ths of a quart of the new 75W90 left over from my transmission oil change yesterday.

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But I have 2.9 quarts of the dirty 75W90 that came out!

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In fact I have 92 ounces of the dirty stuff! :)

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I'm just wondering if it can be used for chain oil, but the fact it may have metal flakes in it is probably the killer on the idea.

Reply to
Chaya Eve

How much would it cost to repair/replace the chainsaw's oil pump if the chunks of shit in your used drain oil clog up the pump?

Reply to
Bubba's Chainsaw Repair

When you use a chain saw, that oil ends up in the environment including your face. Any oil will lubricate the chain, but you really don't want to put toxic stuff in your eyes, mouth, and nose.

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Reply to
Dan Espen

I don't think it's worth it but other than the drip feed the chain, bar, and sprocket are somewhat expendable like bike chains and sprockets.

Reply to
rbowman

I have to say that the feds think of everything, and they worry about lots of things I don't worry about - but - when I'm using the chain saw ... toxic chemicals splashing in my face are the *least* of my safety concerns.

So I may seem crass, and I know the oil goes *somewhere* (just like tire rubber goes somewhere and just like power steering fluid goes somewhere) but on my list of things to worry about - toxic gear lube in my face isn't yet on that list.

But thanks for the extra worry! :)

Reply to
Chaya Eve

Exactly.

Realistically, a chain saw isn't worth repairing since a new one is only $350 and a repair for about 1/3 that price only gets you your used one back.

Then again, there are things to worry about, and there are things not to worry about.

For example, a lot of people worry about climbing a ladder to operate a chain saw to cut off a high tree limb. So they don't do the job because they're worried about falling off the ladder.

If they just had someone hold the ladder, then maybe they wouldn't need to worry so much.

Same here kind of.

If this is a realistic worry that the particles *will* screw up the chain saw, then it's never going to be worth it.

But if it's just one of those running-with-scissors old wive's tales, then it's not a realistic worry.

The problem is that nobody knows - which means I either have to be a guinnea pig or I reason it out or I don't do it. Actually I think someone said in this thread they do it all the time, so maybe I don't have to be the guinnea pig.

Anyway, it was worth the question. I think the answer is that there is a risk of the particles screwing up "something" but that risk has to be assessed versus the benefit (which isn't all that much since chain oil isn't all that expensive).

That's the takeaway.

Reply to
Chaya Eve

Indeed, some folks have too much time on their hands...the amount of oil left in any one area is so miniscule as to be negligible, and a fair amount probably actually ends up on the ends of the sawn material that is removed with the useful timber/cuttings...

The longterm impact isn't all that bad, either--I remember the spot on the farmstead here that was the oil-change location for 50-60 years or more...we just drained the oil into the sandy ground in a given location as was no recycle market back then and was only so much used one could make use of. After a period of time that was a clear spot of ground that stuff didn't grow on, naturally.

But, sometime probably in mid-70s or so, the Co-oP started collecting used oil when they delivered gasoline/diesel/propane so we began catching used oil. At this point and at least by the time we returned to the farm in 2000, it is impossible to distinguish that area from the surrounding--over time even that highly concentrated an area "healed itself" without any intervention. A little chainsaw spray or wipeoff would be virtually impossible to detect within a very short time; it's just not that much of an insult by the limitation of no significant volume is involved.

Reply to
dpb

Every time I walk in the forest, I step across something that is "toxic" whether it's a dead animal or poison oak or berries that will make you sick or just standing water that you wouldn't wash your dog with.

That toxic stuff *grows* in the forest and the forest somehow handles it without the Feds telling me to use vegetable/canola oil (which itself is just not natural).

Anyway, I'm not dissing the vegetable/canola oil idea so much as I'm saying that when I'm using a chain saw, the *least* of my worries are where the oil goes and what happens to it afterward.

When I get to the point of worrying about that, I'll be dead and in heaven by then because all my other worries will have been taken care of.

Reply to
Chaya Eve

I doubt that whatever is in the oil is going to harm a chainsaw bar or chain. I've used everything from 10-40 to vegetable oil. I never tried used oil, but you're not talking about things like valve seals, piston rings, etc. It's a chain moving on a bar. I would think one difference with true chain oil would be the stickiness if you will, ie how well it clings to the bar instead of flying off. But if you don't care how much oil flies off because it's free, does it matter that much?

Reply to
trader_4

On 20-Sep-17 5:09 PM, Chaya Eve wrote: ...

Grok that, too...was just commenting on the magnitude of the "problem" as being mostly made up rather than real.

I'd not be surprised but what there also was some trade group looking for more uses for their particular products funding the "research" driving this, either...

Reply to
dpb

Just make sure you wear your chaps, mesh gloves, steel toed boots, hard hat, and suitable hearing protection :)

Reply to
rbowman

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