3/8 - .325??

[Dan Forsh]

Sorry to show my ignorance here, but I've gotta learn.

Acres site shows my Stihl 028 as using a chain pitch of .325", so I bought a nice genuine Stihl 18" bar which has all the chain stats stamped on the side.

18" .325 0.063 74

I was about the buy a chain to suit, but noticed that the sprocket is stamped as 3/8-7

I know the 7 means 7 teeth, but 3/8? Has this been changed from the standard spocket, or can I run the .325 pitch chain on it?

I know there is only about 1 mm difference between the two, is this a case of close enough or what?

Cheers,

Dan

 

[Freakingstang]

you can run them either way. The .325 may cut slightly faster, but the 3/8 will throw bigger chips. I would only run the right sprocket for the correspondin chain.


Steve

 

[timistall]

Chain has to be .325 0.063 74 links and .325 sprocket(5 USD) Good idea to replace all at once anyway.

 

[Crofter]

No, you cannot run .325 chain on that 3/8 sprocket. Though there is not much difference per drive link, there are about 4 links in contact at once on the sprocket and the difference accumulates enough to make the chain climb a notch and jamb. Chain gauge doesn't matter to the sprocket, but pitch does.

 

[Dan Forsh]

So why does my saw have a 3/8 sprocket on it? The chain manufacturer's website I've just looked at has chain selector option where you have a series of drop down menues to choose from, and on chain pitch it only gave the .325 option for the 028? Has this been mistakenly changed to a 3/8 sprocket or just an option that isn't normally specified?

 

[skwerl]

The 028 can come with either pitch. You can run 3/8 or .325, but you can't mix-n-match different sized components.

 

[timistall]

So why does my saw have a 3/8 sprocket on it? The chain manufacturer's website I've just looked at has chain selector option where you have a series of drop down menues to choose from, and on chain pitch it only gave the .325 option for the 028? Has this been mistakenly changed to a 3/8 sprocket or just an option that isn't normally specified?

The 028 is an older saw. Maybe when new it had 3/8 setup. .325 is the "latest and greatest" for todays small to midsize saws.

 

[Dan Forsh]

Well I've got a nice new .325 bar (I assume it's only spec'ed cause the bar is sprocket nosed) I can get a chain at a decent price, so I suppose the cheap option is to change out the sprocket too?

Okay, if I have to change the sprocket. are these standard ( for Stihls at least)? Do I just get a .325-7 sprocket, or do I need to specify it's for an 028?

Thanks for the rapid response by the way guys, really helpful

 

[Dan Forsh]

Yep, that makes sense to me. Thanks Frank and everyone else who has educated me on this thread.

 

[skwerl]

As long as you specify that it's for a Stihl, you will get the correct sprocket.



More info than you want but there are only 3 common sprocket sizes for all modern chainsaws. Sprockets are either small spline or large spline, with the break being about the 55-60cc range for most brands. For larger saws, everybody uses the same size. A large spline rim sprocket will fit any larger saw of pretty much any brand. For the small spline, Stihl makes theirs a different size than everybody else. So a small spline Stihl sprocket is different from every other brand small sprocket.

Also, .325 sprockets are typically only available in the small spline. You can do some searching and find a 9 pin .325 sprocket for the large spline but it is likely a special order. I've never seen one.

 

[Dan Forsh]

Weird!


I saw Crofter's reply before I responded, but now it's disappeared?

 

[timberwolf]

You may want a 325 8 which is very close to the same diamiter as a 3/8 7.

 

[Dan Forsh]

Okay, one last question and then I think I'm done.

Rim sprocket, which is that? I know there are two different types based on the different saws I have. There are the ones that have teeth and engage the drive links on the chain and there are the ones, like the one in question, that the chain's drive links engage into. Sorry I don't know which is rim and which is the other? Do I get a choice, and if so, is one prefereable over the other?

Dan

 

[Dan Forsh]

You may want a 325 8 which is very close to the same diamiter as a 3/8 7.

That's what Crofter said too, was I the only one to see his reply???

Yes, I do drink on a Wednesday night, but not that much!

 

[timberwolf]

Best thing to do is click on the baileys link above, go into chainsaw parts in the online catalog and there are some nice photos of rims and spurs, that should sort it out for ya.

 

[musher]

That's what Crofter said too, was I the only one to see his reply???

Yes, I do drink on a Wednesday night, but not that much!

He might have deleted his post before your reply. I think the site will let you delete as long as noone has replied to it, or maybe its just a time limit thing.

 

[Dan Forsh]

Thanks Timber, at a guest, I assume rims are what I've got and spurs are the toothed kind then.

Cheers,

Dan

 

[Dan Forsh]

He might have deleted his post before your reply. I think the site will let you delete as long as noone has replied to it, or maybe its just a time limit thing.

That would explain it. Thanks.

 

[Lakeside53]

The 028 is an older saw. Maybe when new it had 3/8 setup. .325 is the "latest and greatest" for todays small to midsize saws.

All the 028's I see had .325 as standard. I notice these as they are they are the only saws I see out here with .325! A few have subsequently been been converted to 3/8. As for "latest an greatest" - that depends on the part of the county you live in... all 3/8 out here with 3/8 picco on the smaller saws, and 3/8 PMN on the very small.

 

[SawTroll]

You may want a 325 8 which is very close to the same diamiter as a 3/8 7.

Maybe, but based on the power level of the 028 and the length of the bar, my guess is that .325x7 wil be the best choise.

..... For the small spline, Stihl makes theirs a different size than everybody else. So a small spline Stihl sprocket is different from every other brand small sprocket .......

I learned that the hard way, but at a later time I was told on this forum that Stihl also used the standard small spline on some models ( some versions of 036/360, and the 290-series ???).

Are you sure that they didn't?