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Chainsaws use oil to lubricate the chain. The usage is quite minor, probably less than 1cc per minute of work. The oil is normally supplied from a refillable compartment to the chain only when the chainsaw is running.

How is the delivery managed?

A pump? The capillary effect?

If it's a pump, I'd be interested in details - I mean, I have a hard time imagining a pump this slow (<1cc/min) supplied from the high-RPM engine... or does it use an extensive gearbox to slow down? A separate motor?

[note: I mean the oil used for chain lubrication, not mixed with fuel for the two-stroke engine of motorsaw]

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    $\begingroup$ To answer the trivial part of your question: Yes, there is a pump, as shown in this short (01:37) youtube video. I don't know the specs on the pump, it probably varies by mfr/model. $\endgroup$
    – Air
    Mar 8, 2015 at 0:41
  • $\begingroup$ @Air: Thanks. While I guess there may be a number of solutions used, just an example one, some fairly commonly used solution, will suffice for an answer. $\endgroup$
    – SF.
    Mar 8, 2015 at 0:58
  • $\begingroup$ Also worm gears can easily reduce down at a 100:1 $\endgroup$
    – ratchet freak
    Mar 8, 2015 at 15:04

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Delivery is through a small nozzle that fills a slot behind the bar that leads into a hole in the bar which then leads to the chain. This slot is so that when adjusting the tightness and move the bar it will still deliver oil.

The pump is driven by a worm gear which is coupled to the sprocket that drives the chain or directly to the drive shaft (depends on the model). For those that are coupled to the chain sprocket you can turn the chain to pump oil manually, for the other type you can run the engine. This lets you ensure the chain is oiled before you fire it up after changing the chain.

This video show a disassembly down to where the worm gear is.

The following picture comes from patent US5236314 and shows the pump assembly and mechanism.

enter image description here

Component 9 is a shaft that is rotationally coupled to the shaft driven by the worm gear but will oscillate as it rotates because of groove 12 and the cam 14. It is pulled back by washer 15 down to a point defined by settable screw 18. So when slot 21 is near the intake the chamber will expand and when it reaches the discharge side the chamber will contract expelling the oil.

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  • $\begingroup$ I still wonder what type of pump is used, and how dosage of oil is regulated - in all chainsaws I used there was a regulation screw that allowed free tuning of oil dosage. $\endgroup$
    – SF.
    Mar 9, 2015 at 8:53
  • $\begingroup$ @SF. I found a relevant patent :) $\endgroup$
    – ratchet freak
    Mar 9, 2015 at 9:05
  • $\begingroup$ And it plug with sawdust very easily. $\endgroup$
    – blacksmith37
    Mar 21, 2018 at 21:58
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I sent this question along to a forester of 20+ years and this was his response:

So...... back in the day......... the first saws had a manual oiler. This was a younger lumberjack in training who operated the oil can. He held this job until one of the more senior lumberjacks cut off something vital and he was promoted.

The next generation of oilers was still manual. There was a thumb plunger on the case. It was located near the center of the case and was operated by the same thumb/hand which operated the throttle. The theory being that you could give one good squeeze and cut/oil at the same time. the operator was also able to titrate the oil use to the dryness or wetness of the wood.

One of the posters was correct in that there have been worm gears used also. These are very effective in that they are throttle based. they work as fast as the saw requires and in theory you don't burn up bars and chains. There is an adjustment screw which has numbers from 1-5 with the preset usually being a 2. I believe that this is the current style in use. The output is based on a motor speed of 9000 rpm. There are some other pump styles in use but these are the most reliable. They are mechanical. They leak on the floor when not in use. Gravity!

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