Why to my chains' gear teeth keep getting marred up?

[ForTheArborist]

Chains keep popping off of the bar on me. When I inspect the chains, the gear teeth are marred so that they either will not wrap around the bar tip, or they will not fit in the bar slot any more. That is why they pop off the bar, but I don't know what is causing these teeth to get beat up like that. I'm having to throw away perfectly good chains.

 

[alderman]

If the teeth are marred, they aren't perfectly good chains.
Check your drive sprocket and bar sprocket too see if they match. Also the guage of the chain must match the guage of the bar.

The pitch of your chains must match your sprockets.

 

[stoking]

If the chains are the correct size you probably just have burrs on the teeth. That happens often after you throw a chain. If that is the case just use a flat file and file them down.

 

[adkranger]

+1 on checking the drive sprocket. If it's worn beyond limit it can damage the drive links, so they don't ride in between the bar rails properly, or on the sprocket tip. Causing it jump the chain, damaging the links further. Of course if the guages don't match, can cause the chain to jump, damaging the drive links in the process. Chicken or egg? You'll have to do a little investigation.

BTW, you don't necessarily have to throw the chains away. You may, and I say may, be able to dress up the drive links with a file to put back into service. Just as long as the overall shape isn't too messed up. I've fixed many chains that had minor damage to the tip of the drive link(s). They will damage your bar groove if run for any length of time.

 

[GASoline71]

Drive sprocket shot. Or wrong size chain for the sprocket, or wrong size sprocket for the chain...

Gary

 

[JJuday]

My 066 did the same thing, the sprocket was fine, but the bearing was not. Got a rehab kit and just decided to replace it all with new and kept the old sprocket for a spare. Grab sprocket and see if it has side to side play, if so you have a junk bearing. JJuday

 

[Brushwacker]

Most my chain throwing problems come from the sprocket in the nose of the bar wore down to a point it throws the chain easy , especially when it comes into contact with pinny limbs or small brush. After it throws it once , it progressively happens more often so I usually go for a new sprocket tip or bar soon after I notice the condition. I change drive sprockets frequently because they'll stretch new chains when they get a groove in them. If I have stetched chains I try to use them on well used bars and sprockets that have some wear. New works best with new, Sprockets with some wear match up better with chain that is stretched from previous use.

 

[Gypo Logger]

Sounds like the sprocket and chain are a mismatched pitch. If the drivers are peaned, simply loosen the chain so it sags and goose the throttle, that will deburr the drivers, but be careful, I saw a guy bust a crank when he tried to marry 58 thou to a 50 thou bar on an 044.
John

 

[AUSSIE1]

If a chain is tensioned too loose, it can throw.
Redress the drive links with a file or a Dremel mounted sanding drum.

 

[Cantdog]

First thing you have't furnished enough info as to what type of saw, what type of drive, sizes of chain and type/size of bar etc. With so many varibles it could be something simlpe to rather complex. All the above answers could be correct. We have seen folks with B&C problems that ranged from plain old worn out to trying to run 3/8 chain on a .325 drive sprocket.

My first guess would be you have a rim drive sprocket and it is so worn that the drive teeth are protruding past the inside and coming in contact with the spline of the clutch drum, causing the tips too mushroom and no longer fitting in the bar rail groove properly. Again this is just a guess based on the info. Pics would be very helpful.