How to know when chain is tight enough?

Hubby asked me to post his question: We have an Craftsman electric chain saw (model 358.341141 if it makes a difference) The instructions tell me that for tightening the chain, I should "continue turning the adjusting screw until the tension is correct."

The question I have is how do I know the tension is correct?

I am sure that I could overtighten it, and if I do I bet that it would cause excessive wear on the bar. Too loose and I can just picture the disaster as the chain comes off. What I have done is tightened to the point where if I try hard I can not lift the chain out of the grove on the rail, but there is still some play in the chain.

Bottom line, am I about to kill myself?

When tightening a chainsaw chain you should hold up on the bar to take any tension off the bar and tighten the chain up to the bottom of the bar rail almost snug but not too tight. Once tightened you should be able to move the chain around the bar freely buy gloved hand with out too much pressure.

*If chain is hanging from the bar = too loose.
*If you can't move by gloved hand around the bar = too tight

A loose chain can cause extra ware on the bar and also causes the chain to jump from the bar ( off the bar )

This works with all chainsaws except for a "Pro model" gas chainsaw as with a Pro chainsaw once the chain is up to the bottom of the bar rail an extra 1/8' - 1/4" turn to tighten the chain a little extra is needed.

***Don't forget your personal safety gear when using a chainsaw.
PPE - Personal-Protective-Equipment

Good question. My Poloun manual says to tighten until I have 1/8" of play when pulled away from the bar. I can pull lightly, moderately and quite firmly and get different amounts of play...so I'm still unsure. Also, "spins freely" is a bit vague depending on how much pressure is necessary. I kinda go with medium pressure to check but still wonder....

It's one of those things that's hard to explain adequately, but you know it when you see it.

Basically, if it's not hanging loose and you can still turn it fairly easily by hand, it's tensioned right.

However, this all gets very confusing when you have a worn sprocket or chain that changes tension as you move the chain around the bar. The trick there, until you can address the core problem, is to make it tight enough so it won't derail, but loose enough so that it can turn without damaging the chain.

If your chain rides up and down as you turn it around the bar, then you need a new sprocket, and probably a new chain as well.

In one of the first things I noticed about switching from a cheap junk saw to a good quality one is that the chain tension was much easier to adjust and did not need to be adjusted as often.
Most of the time I can tell if the tension is right by what it sounds like.
Also if the chain is run loose a lot you can get a worn spot on the bar just where the chain is coming off the nose sprocket. Flip a bike upside down sometime and watch the chain as it goes around the sprockets, it will want to follow the sprocket around even after the point you think it should be on its way to the other sprocket.
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Andre' B.

If it's too tight, you can sure hear that. And you're right about a loose chain wearing everything out prematurely.

And I think Roospike alluded to this: When you tighten the chain, grab the tip of the bar after you loosen the retaining bolts and pull it straight up, so that any slack in the chain shows up on the bottom rail of the bar. Then tighten the chain. If you don't pull the bar tip up, you won't be able to tighten it properly. Good saws make this relatively easy to do, while some cheaper saws require (at least) three hands to do it right by yourself.

I do what Eric and Roo do also.

The only thing I can add is support the bar tip up on a piece of wood to take up any slop or wear in the saw when adjusting chains. I've had a loose chain when the bar moved up just after tightening the chain on saws when they are next used.

Also be aware that a new chain will stretch considerably after it's first use and will need to be re-tightened.