knowing there is no such thing as a stupid question; can you use used motor oil as bar oil for a chainsaw?

yes you can just watch to see it don't run out faster than regular bar oil

Yes BUUUT you will have increased bar and chain wear and more oil pump wear.The bigger the saw and the longer the bar the worse it will be.A good quality bar oil is way cheaper than bars and chains.I've ran a logging company for 20 years and have tried to cut that corner and always go back to Stihl baroil every time .The cost of bars and chain just aint worth the savings of cheap oil.

Yes you can use used motor oil on the bar if you like buying bars and chains. There is a reason why they can sell bar oil.

I don't think so since used motor oil has impurities in it including tiny bits of metal.

I do use used motor oil to oil the chain on my single chain hay elevator.

I've used strained drain oil a lot for bar oil. It gets you by, but it's not great. Mixed 50/50 with good bar oil it's better. You can buy bar oil on sale for as little as $7.00 a gallon around me and you can get it cheaper in 5 gallon pails if you can find a supplier that will get it for you. Everything is cheaper in bulk. If you want the high dollar non-mineral oil "green" stuff, I don't think you can get that for cheap anywhere.

I guess if you are a professional cutter or such it would pay to use commercial bar oil, but I use old motor oil.
I have done so for over 40 years. My first chain saw, I wore out the engine from use and never replaced a bar. The chain I did. Then I bought one of those rebuilt Poulans. I have replaced the bar on it once and chain about three times. These were both smaller 16" and the chains were replaced as I re-sharpened them after they got dull.

I have 22' Homelite, bought in the early 80's that I have never replaced the bar and have replaced the chain about three times. Last year I bought a new 18" Sthil as the Poulan is about used up.

I heated with wood for about 10 years before I got natural gas service here and cut about 8 chords a year. Now I only use the saws for cutting about 30 trees a year on my property as I am trying to mitigate for protection against wildfire. I live near the big Black Forest fire that burned 15,000 acres a year ago and it was stopped about 500 yards from my place.

The big Homelite, I mostly use it for cutting 3x3 x8 foot hay bales in half length ways now days to make it easier for me to feed.

I put the used motor oil in 2&1/2 gallon jugs and let it sit to let the sludge, if any, sink to the bottom and then pour off the top after it sets a month or so.

Miscellaneous, medium use, I would use the motor oil ( 5-30 weight),full time use,maybe not.YMMV

thanks for the responses. Any other uses for used motor oil?

That what I don't use, I recycle by taking it to Walmart, Sears, Advanced Auto, AutoZone. They all take it now.

Got to be careful, you can't just dump it out on the ground now for dust control.

I put used motor oil on my wagon flats. Just brush it on like painting it. Makes them a little bit more resistant to weather. Also put it on the tops of my fence posts to help protect the sawed end. I also use it to oil the chains on some equipment like floor and apron chains on silage wagons and roll baler etc...

Same as Lee does for me. I also use it to get brush piles burning, for spraying down on vehicle frames and springs (if you don't live in salt country you wouldn't understand that) and for whatever else I can think of. At one time you could put drain oil in a paper bag in a milk crate and tip it a little, the oil would slowly filter through and you'd have clean oil when you got done. It seems paper bag making has changed because that doesn't work any more. I've let oil sit for a year or so and sucked the clean-er oil off the top too. Used it in bad leakers/burners that would use a gallon in an hour while running just to get by. I've also seen drain oil filtered and mixed with diesel and used without problems in older diesel Cat engines, stuff from the 40's and 50's.

we have just strained the oil through a cloth and poured it in the fuel tank on my 1991 kenworth 425 cat with no problems. The engine has only been overhauled 4 times in 2.7 million miles.