Tight/Loose chain discovery.

[67L36Driver]

Saw is a newly built Farmertec 365. Bar is a like new 20” Oregon or Windsor robbed from my 61 Rancher.

Chain came with the Rancher from a barn clean out.

After some runtime I noticed the slack.

Adjusted that out.

Then I couldn’t roll it all the way ‘round. WTH !!

So added enuff slack to get it moving. Marked the chain at max slack.

Pulled off the chain and examined each and every preset and driver.

Found that the chain has 58 drivers of Stihl chain.

With 14 drivers of IDK added to it to make 72.

Maybe the Stihl part has more wear on the pins/rivets making the added length produce the tight/loose condition.

[emoji848]

There is no visible run out on the new rim drive drum or rim. Bar sprocket, ditto.

 

[67L36Driver]

I was expecting to find a random .325” or .404” preset but didn’t.

 

[AlfA01]

Do all the drivers have the same thickness?

 

[67L36Driver]

Do all the drivers have the same thickness?

Thickness = .050” gauge.

Front to back length? I haven’t measured that. And don’t know if I can accurately.

 

[AlfA01]

Thickness = .050” gauge.

Front to back length? I haven’t measured that. And don’t know if I can accurately.

I would think that would be standard if all the links are the same pitch. Hmmmm. Did you give the bar a look for straightness, burrs or other damage?

 

[Northwet]

Is it the chain? Maybe the rim/sprocket on the clutch isn't round.

 

[T.Roller]

Is it the chain? Maybe the rim/sprocket on the clutch isn't round.

+1

 

[T.Roller]

I'd try another rim

 

[p61 western]

I had a fair amount of trouble with the clutch drum and rim that came with my kit. It may or may not be your problem. I replaced both, and fixed my problem.

 

[nohoff]

Some manufactures have different length between the rivets on the driver and the teeth/link.
If you mix Stihl chain with oregon chain you will get a different pitch on the connection.



This is a example.
But some manufactures have different distance between the rivets and that causes different distances between the drivers if you mix Stihl/Oregon chain for example.

 

[Basher]

Try a known good chain, that will eliminate that frankenchain, if there is still tight - loose conditions I would suspect the drive rim or sprocket but even bar nose sprockets sometimes cause this condition.

 

[Stump Shot]

The rim sprocket, oh it's round alright, so is the hole in the middle, the problem is it's not centered and is going around like a tire on a clown car. Toss it and replace with a good one, or the only thing it will "drive", is you nuts.

 

[Chainsaw Jim]

The oddball is McCulloch chain and I'm assuming @heimannm will know the exact models it was made for.

 

[67L36Driver]

The oddball is McCulloch chain and I'm assuming @heimannm will know the exact models it was made for.

This 14 driver length?

U R the first guy to make sense.

It very well could be the weird .354” pitch McCulloch used at one time.

 

[heimannm]

No it's not .354 pitch, 370 is 3/8 .050. The 354 pitch would carry a 350 (.050) or 358 (.058) stamp on the drive links.

If you leave the chain loose enough, you can run 3/8 LP chain on a .354 sprockets...for a while anyway.

Mark

 

[Basher]

The rim sprocket, oh it's round alright, so is the hole in the middle, the problem is it's not centered and is going around like a tire on a clown car. Toss it and replace with a good one, or the only thing it will "drive", is you nuts.

I have seen this on a few AM rim drives, not mine as I only run OEM . The AM ones can also be made of rather soft metals, have not ever seen a bad OEM rim yet.

 

[Stump Shot]

No it's not .354 pitch, 370 is 3/8 .050. The 354 pitch would carry a 350 (.050) or 358 (.058) stamp on the drive links.

If you leave the chain loose enough, you can run 3/8 LP chain on a .354 sprockets...for a while anyway.

Mark

Yes, here is some.

 

[fearofpavement]

I've had this happen on saws and a different chain always solved the problem.

 

[Basher]

Off centered rim drives and badly worn sprockets are the most common reasons I have seen. Seldom see a chain made up of different makers sections unless I make them for my own use, have done that but they were compatible.

 

[Homemade]

I have seen this on a few AM rim drives, not mine as I only run OEM . The AM ones can also be made of rather soft metals, have not ever seen a bad OEM rim yet.

Have you had any problems with Oregon brand? They are the only ones I seem to find in 3/8 x 8.