# difference between an .325 and 3/8



## roundhead (Mar 21, 2012)

I need to get a bar and chain for an 039 rebuild. I ran it with my .325 chain and 7t sprocket to try it out, but it had an 8T 3/8" sprocket. Is there much difference in the two sizes? How do you know when it is time to replace the sprocket? the 3/8" sprocket has notches on it but my .325 does not. Is that normal or is that wear?


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## Eecho (Mar 21, 2012)

The pitch .325 is a smaller top cutter and tie strap it is easier to turn for a saw . The 3/8 is a bigger top cutter and tie strap . Mainly in a 20 " chain has more cutters in .325 than the 3/8. Some guys say that .325 is better for hardwoods then 3/8 due to more cutters and less bite . I personally use 3/8 on my saws that the displacement is in the in between range. 3/8 is much easier for me to see when filing and I think it holds up a little better then .325 . Sprockets are suposed to be changed every two chains but that mainly revolves around wear it is showing . I have two saws that run .325 but they were upsized from 3/8 lo profile which is even smaller then .325 in cutter height.


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## deye223 (Mar 21, 2012)

looks like there will be a few replys before i get this done 1st in pic is new 2nd 10hrs on it 3rd is what i call buggered and i don't let my sprockets go this long







i change every 3 chains


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## Wolfcsm (Mar 21, 2012)

roundhead said:


> I need to get a bar and chain for an 039 rebuild. I ran it with my .325 chain and 7t sprocket to try it out, but it had an 8T 3/8" sprocket. Is there much difference in the two sizes? How do you know when it is time to replace the sprocket? the 3/8" sprocket has notches on it but my .325 does not. Is that normal or is that wear?



I think that you will find that .325 vs .375(3/8) chain is mostly a matter of personal preference. I am using both and really see little difference. the number of teeth on a sprocket is also a matter of what you want the saw to do. Right now, I have an 8t .325 sprocket on my 310 -stelth 390, using Oregon LGX chain. Not a bad setup. I have 7, 8 and 9 tooth .375 sprockets to try, also with LGX. I have used the 7 tooth sprocket since I bought the 310. Since the upgrade and mad, I want to see how a 8 or 9 tooth rim will work.

Hal


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## handyrandyrc (Mar 21, 2012)

I asked Google. 

3 divided by 8 (3/8) = .375" vs .325"

There is .05" difference between them. FIVE HUNDREDTHS of an INCH.


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## SawTroll (Mar 21, 2012)

Wolfcsm said:


> I think that you will find that .325 vs .375(3/8) chain is mostly a matter of personal preference. I am using both and really see little difference. the number of teeth on a sprocket is also a matter of what you want the saw to do. Right now, I have an 8t .325 sprocket on my 310 -stelth 390, using Oregon LGX chain. Not a bad setup. I have 7, 8 and 9 tooth .375 sprockets to try, also with LGX. I have used the 7 tooth sprocket since I bought the 310. Since the upgrade and mad, I want to see how a 8 or 9 tooth rim will work.
> 
> Hal



I assume the .325 chain is LPX, as LGX doesn't exist in that pitch.



handyrandyrc said:


> I asked Google.
> 
> 3 divided by 8 (3/8) = .375" vs .325"
> 
> There is .05" difference between them. FIVE HUNDREDTHS of an INCH.



The problem with that is that 3/8" doesn't have a .375 pitch, but rather .367.


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## starsailor (Mar 21, 2012)

roundhead said:


> I need to get a bar and chain for an 039 rebuild. I ran it with my .325 chain and 7t sprocket to try it out, but it had an 8T 3/8" sprocket. Is there much difference in the two sizes? How do you know when it is time to replace the sprocket? the 3/8" sprocket has notches on it but my .325 does not. Is that normal or is that wear?



The difference is 0.050"


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## Eecho (Mar 21, 2012)

SawTroll said:


> I assume the .325 chain is LPX, as LGX doesn't exist in that pitch.
> 
> 
> 
> The problem with that is that 3/8" doesn't have a .375 pitch, but rather .367.



Actually isnt it .372 lol if a 32nd of a inch is .031 on a caliper but theres probably other numbers behind that decimal point im forgetting .


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## bootboy (Mar 21, 2012)

100/8 = 12.5 /100. therefore, 12.5 = 1/8
3/8 = 12.5 x 3/100. therefore, 37.5 = 3/8


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## blsnelling (Mar 21, 2012)

No way should a 039 have an 8-pin 3/8 sprocket on it. That is way bigger than a 7-pin .325. You should be running a 7-pin 3/8.


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## fearofpavement (Mar 21, 2012)

blsnelling said:


> No way should a 039 have an 8-pin 3/8 sprocket on it. That is way bigger than a 7-pin .325. You should be running a 7-pin 3/8.




I agree with Brad (this time) and the 039 is well suited for 3/8" chain but an 8 pin is overly optimistic for it's power. (that 8 pin setup would be fine for a large saw like a MS660)

Essentially the saw manufacturers set saws up with an appropriate bar/chain/sprocket combo. Because many people have multiple saws, it is tempting to try to run the same chain on all of them. In reality, this is typically not a good idea because the saws are different power ranges.


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## roundhead (Mar 21, 2012)

blsnelling said:


> No way should a 039 have an 8-pin 3/8 sprocket on it. That is way bigger than a 7-pin .325. You should be running a 7-pin 3/8.



OK pin = tooth?
my 290 has a 7t with a .325 chain
you are suggesting that the *039 *be run with a 7t 3/8 chain.
are all these incompatible, meaning that you will need a specific sprocket and bar for each specific size chain? wouldnt the 8t give you more torque?


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## sunfish (Mar 21, 2012)

roundhead said:


> OK pin = tooth?
> my 290 has a 7t with a .325 chain
> you are suggesting that the *039 *be run with a 7t 3/8 chain.
> are all these incompatible, meaning that you will need a specific sprocket and bar for each specific size chain? * wouldnt the 8t give you more torque?*



8 pin will give more chain speed and less torque.


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## Wolfcsm (Mar 21, 2012)

blsnelling said:


> No way should a 039 have an 8-pin 3/8 sprocket on it. That is way bigger than a 7-pin .325. You should be running a 7-pin 3/8.



Going to try it. May be that either an 8 or 9 pin rim is too big. Not really going to know until I put my saw into wood. Will sure let you know how it works.

Hal


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## blsnelling (Mar 21, 2012)

Wolfcsm said:


> Going to try it. May be that either an 8 or 9 pin rim is too big. Not really going to know until I put my saw into wood. Will sure let you know how it works.
> 
> Hal



Don't waste your time, unless you're putting it on your 880


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