Drive sprocket wear. How long should one last?

[Joseph Acquisto]

Wondering about "real world" wear of chain drive sprockets. How often do they need replacement. I saw one supposed Oregon chain care advisory say to chuck them out every two chains. I guess (hope) they meant after two chains have been resharpened till useless.

I've changed one or two sprockets and the "mark up" almost immediately. I changed them when the wear began to bother me, but did not notice any performance issues. No fast chain wear or tossing chains anyway. Not that I am a performance expert at all.

 

[HumBurner]

I generally run three chains per sprocket. I often forget to swap the chains out as regularly as I should. Run the chains until the teeth are breaking off and/or down to toothpicks.

Unless totally trashed, I keep the used sprockets. Never know when you might find some still-good used chains.


I've gotten sprockets on used saws that looked like the sprocket had 5-10 chains run through them to end of life.

 

[Mad Professor]

I generally run three chains per sprocket. I often forget to swap the chains out as regularly as I should. Run the chains until the teeth are breaking off and/or down to toothpicks.

Unless totally trashed, I keep the used sprockets. Never know when you might find some still-good used chains.


I've gotten sprockets on used saws that looked like the sprocket had 5-10 chains run through them to end of life.

Rotating chains is a good thing. Run chains/rim/sprocket until they are shot. Yes, chains will still cut good until so filed down the teeth start snapping off.

I think this one was shot......

 

[user 122190]

A long long long time. My ms290 that I had for 10 years, cutting 7, or 8, or more cords a year, and I never had to change the sprocket. Probably 1.5 chains a year, about...

 

[Joseph Acquisto]

These comments are for general chainsawing? Milling would maybe be a different deal?

 

[PV Hiker]

How the chain is tensioned makes a difference. Too loose have more slop with pounding drive links. Removable Rim sprockets can be removed and flipped over to extend life.

 

[Lightning Performance]

The spec is 0.020 wear.
Most go longer or until the chain starts to feel jumpy when tightened and turned by hand.

 

[gnef]

I think you just have to measure the wear (the stated tolerance is stated above), and swap them when you feel uncomfortable, which could be when the .02 depth is met, sooner, or later depending on your comfort level.

Doing things by chain may give you a good indicator when to check, but considering that for saws that use 3/8" chain, it could be a 16" bar or 36" or longer, two chains can have drastically different wear on the sprocket just due to the number of drive links that rotate on it depending on length of bar/chain.

I primarily mill, and have a 56" setup with 3/8" chain, so it is 168 drive links per chain, and I rotate through 6 chains that I keep on hand. I can't do it by number of chains. I am still on most of my original chains (hit a lag bolt with one that broke the chain and had to throw it away), but have already changed out the rim on my 661 twice now - probably earlier than needed, but it is cheap enough to me that it just gives me peace of mind.

 

[Coralillo Lo Pro]

Changed out the spur sprocket on my 880 after a few years of milling, didn't seem like I'd used it THAT much, but I guess a decent number of hours on the saw. It disintegrated completely in the end, wrecked a chain. Kept experimenting with different chains so never wore any out to judge by that count. Depends a lot on steel quality too. My guess is most sprockets are made from pretty cheap steel now that doesn't last long. American made ones by a company like 6K probably last a great deal longer but also cost 4-5x as much. Like gnef says, the standard ones are so cheap you can replace them pretty regularly for peace of mind.

 

[Joseph Acquisto]

From what I've seen so far sprockets are not that cheap for the 029, at least for the 8 tooth version. As I add up what I might need to for this experiment I am tempted just to spring for a bandsaw mill. Much smoother results and a lot safer. But, at least 10x the dollars, so . . .

 

[Coralillo Lo Pro]

From what I've seen so far sprockets are not that cheap for the 029, at least for the 8 tooth version. As I add up what I might need to for this experiment I am tempted just to spring for a bandsaw mill. Much smoother results and a lot safer. But, at least 10x the dollars, so . . .

??? You have a rim sprocket or spur? 8 tooth .325 rim sprockets for the 029 can be got for nothing, like 5 for $15 on Ebay. If you're running a spur I'd switch the drum to a rim sprocket setup.

 

[Philbert]

Like the tires on your car.

Some folks replace them by tread wear. Some wait until the wear bars show. Some run them bald, as long as they hold air.

Philbert

 

[rogue60]

Like the tires on your car.

Some folks replace them by tread wear. Some wait until the wear bars show. Some run them bald, as long as they hold air.

Philbert

Going on that analogy I run them tell the tyres blowout I get my monies worth lol
Only one dealer in my town they charge over 30 bucks for one rim.

 

[Philbert]

Going on that analogy I run them tell the tyres blowout I get my monies worth lol
Only one dealer in my town they charge over 30 bucks for one rim.

Same with all saw components? Or just sprockets?

Philbert

 

[Joseph Acquisto]

??? You have a rim sprocket or spur? 8 tooth .325 rim sprockets for the 029 can be got for nothing, like 5 for $15 on Ebay. If you're running a spur I'd switch the drum to a rim sprocket setup.

Pretty sure it is a spur (a.k.a. "chain sprocket"?). From what I recall when chainging chains, it is a one piece "drum and drive", with a fairly "wide" surface for chain drive. Like the drive "spur" or gear was brazed onto the drum. Guess I need to go take it apart to be sure.

The sprocket is a lot cheaper than the drum but the kit to change over is about what the spur costs.

Other than the part cost, why do you recommend changing?

 

[Coralillo Lo Pro]

Yeah that's a standard spur sprocket. You have to replace the whole drum when you replace the spur cause it's all one part. Once you have a rim drive, you only ever have to replace the rim sprocket. Rims float in and out some easily to maintain alignment with the bar better. They may be more efficient too, not sure about that or not. Also have the option to switch up sprocket size if needed, can run 7 or 8 tooth rims for more speed less torque with 8 tooth, less speed more torque with 7 tooth. I switched the 880 to a rim sprocket drum when I wore out the spur. You can tell clearly when a spur is worn out by the grooves dug into it by the chain. I'd wear out your spur than switch to a rim drum.

 

[gnef]

Pretty sure it is a spur (a.k.a. "chain sprocket"?). From what I recall when chainging chains, it is a one piece "drum and drive", with a fairly "wide" surface for chain drive. Like the drive "spur" or gear was brazed onto the drum. Guess I need to go take it apart to be sure.

The sprocket is a lot cheaper than the drum but the kit to change over is about what the spur costs.

Other than the part cost, why do you recommend changing?

Ah, I made the wrong assumption that you were talking about the rim sprocket, which is pretty cheap to replace.

I think for you, it is really about personal preference and how much you use the saw. I would say that if you haven't needed to replace the spur in a long while, a rim won't really benefit you, and the spur is easier to get a chain onto if that matters to you.

If you are going through a spur a year, and use your chainsaw a lot, then it could make financial sense to swap to a spline and rim setup - it will be more expensive up front to change out those pieces, but afterwards you should be able to replace multiple rims before needing to change the drum with the splines on it. While you are at it, you can check the needle bearing (I replace mine as part of regular maintenance, and also clean all those small parts in an ultrasonic bath after every long milling session).

I am personally partial to rims as that's what I have on my pro saws (MS400, and two MS661), and only my MS250 was a spur, but now it has a pulley drive for a planing attachment. The MS250 did just fine on the spur, but I wasn't cutting heavily with it either, and never wore out the first spur even.

 

[Philbert]

If a spur sprocket is still good, no reason to replace it. If it needs replacing, it is worthwhile to look at changing over to a rim sprocket system, even if a few dollars more.

But rim sprockets are not available for all saws (have to find the correct clutch cup / drum). Especially, for some smaller cc and consumer saws.




Philbert

 

[Joseph Acquisto]

If a spur sprocket is still good, no reason to replace it. If it needs replacing, it is worthwhile to look at changing over to a rim sprocket system, even if a few dollars more.

But rim sprockets are not available for all saws (have to find the correct clutch cup / drum). Especially, for some smaller cc and consumer saws.

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Philbert

Mine is definitely the Spur Sprocket. I'm gonna guess the middle wear pattern is "I guess I should think about replacing this soon" and the right most is "Holy wood chips Batman, why haven't I changed this yet"?

 

[Philbert]

Some people wait until they look like the one in Post #3, by @Mad Professor.

At that point, a user could experience erratic chain tension, performance, etc.

Philbert