No wonder people are having tension problems. Not just Oregon sprockets…

[IntegrityCarpentry]

So are there like just 3 sprocket (rim) manufacturers with low tolerance? I have seen a fair amount of this from Oregon. I have heard about issues with Stihl sprockets, now I see them myself. I got 2 new Stihl sprockets from different locations at different times. Both look like the off Oregon ones I have seen and had. At first glance it won’t seem like anything, but I have ran sprockets like this and you get the chain tension that changes as the chain rotates. In one place it’s tight, move it 8” and it gets more loose. Last night I ordered oregon rim sprockets from 2 different places. I have seen some for sale made in USA and Switzerland, pics of the USA made ones seemed to have the same issues. This almost makes me make an adapter and have them machined…do you just have to order them in bulk and pick out the good ones. This is nuts! Is there anyone else who is particular and found a solution/supplier?

In the pics, the first one the pins are flat and flush, 2 are flat. As you rotate they get lower and get rounded. It doesn’t look like much but it’s enough to be annoying when you don’t like to run a too tight chain.

 

[IntegrityCarpentry]

I knew the generic ones were problematic, I have seen that from someone I know with a bunch of unmarked plain sprockets

 

[rogue60]

The drive setup on a chainsaw is about as it crude as ya can get from the sloppy drum that kind of gets "trued up" when the clutch shoes engage to the loose fitting rim's is nothing precision about it. And of course the more a saw is used the worse all those sloppy tolerances get.
Personally I've always just rotated the chain over you can feel the loose/tight spots quite easily,
I just adjusted the chain at a loose spot never had a problem doing it like that for the last couple decades and that's with sprocket nose and hard nose bars.

Stihl rim's are like $30 for one in my town so yeah send all ya "not true" rim's my way I'll run em no problemo..

 

[NSEric]

The 8 pin rim sprocket on my clone saw is like that.
It looks bad when you spin the chain by hand as it goes from tight to a little loose but it doesnt hurt anything while cutting wood lol.

 

[IntegrityCarpentry]

The drive setup on a chainsaw is about as it crude as ya can get from the sloppy drum that kind of gets "trued up" when the clutch shoes engage to the loose fitting rim's is nothing precision about it. And of course the more a saw is used the worse all those sloppy tolerances get.
Personally I've always just rotated the chain over you can feel the loose/tight spots quite easily,
I just adjusted the chain at a loose spot never had a problem doing it like that for the last couple decades and that's with sprocket nose and hard nose bars.

Stihl rim's are like $30 for one in my town so yeah send all ya "not true" rim's my way I'll run em no problemo..

$30 that’s crazy. We have 2 stihl dealers and at the cheaper one they are $9.

The 8 pin rim sprocket on my clone saw is like that.
It looks bad when you spin the chain by hand as it goes from tight to a little loose but it doesnt hurt anything while cutting wood lol.

I understand it works, but it’s not ideal. Somewhere there have got to be some symmetrical rim sprockets.

 

[NHden]

Sorry for late comment. I run rims on several saws and will check this out. If necessary, I'll throw a rim onto a lathe arbor and precisely machine the OD, removing the variation ... if it doesn't create other issues.

 

[Syflan]

So the pins aren't even... doesn't the chain run on the machined rim of the sprocket?
What am I missing?

 

[Lightning Performance]

So the pins aren't even... doesn't the chain run on the machined rim of the sprocket?
What am I missing?

If it isn't running true it's loose or tight as they go around. Had few a two years ago in 8p 375. Bought ten and two were scrap. Out of round and way way off center. Cheap ones... so no big deal.

 

[Breckinridge Elkins]

I would guess the drive shaft hole is not centered, and thus the outside circumference describes an ellipse as it rotates. In other words, the sprocket is out of round. We see this all the time with bike sprockets, causing a tight/loose/tight condition as the sprocket rotates.

 

[Dennisthemenace]

They wear in in a tank or 2

 

[buzz sawyer]

So the pins aren't even... doesn't the chain run on the machined rim of the sprocket?
What am I missing?

Right, assuming the machined area is concentric with the inner diameter.. Sometimes it is not.

 

[bwalker]

I would not loose sleep over this. Just run them. And for the reasons @rouge60 mentioned.