Chain Pitch, What's the Difference?

MtnHermit · Jan 6, 2009

Just a little education, why do I care about subtle differences in chain pitch? If you look at the MS260 page one of the "Features" is the option of 325” or 3/8” pitch. Gee .325 or .375 would seem trivial.

Please explain.

Thanks

xcr440 · Jan 6, 2009

I difference is big on the drive sprocket. The measurement is from rivit to rivit .

TRI955 · Jan 6, 2009

MtnHermit said:
Just a little education, why do I care about subtle differences in chain pitch? If you look at the MS260 page one of the "Features" is the option of 325” or 3/8” pitch. Gee .325 or .375 would seem trivial.

Please explain.

Thanks

I know a lot of guys like to keep the same chain on as many of their saws as possiable, keeps things much simpler (only need one size file). I personally like the .325 on my saws, it frees up a little power for the saws. Just my .02,
Mike.

brages · Jan 6, 2009

0.375 has fewer and bigger cutters.

Now, I'm a newb, so I don't understand this stuff that well.

It seems to me that the point is generally to set up your saw so that it will cut as fast as possible. So I would think it would be smart to run the smallest chain that is appropriate to your saw, unless you are wanting to be compatible with other saws you have.

Wouldn't the fastest setup for a 260 be 0.325 narrow kerf?

What if you put 3/8" low-profile (picco) on it? What would be the disadvantage?

I'm thinking that the general rule is that bigger chains are more durable but require more power for a given cutting speed.

PB · Jan 6, 2009

The 3/8" (.375) is a larger chain with a bigger cutter tooth and will take a larger bite of the wood. You need a larger saw to pull this chain, and it is the standard size on most saws over 55cc. Smaller saws do better with the .325, as it takes a smaller bite and therefore doesn't need as much power to pull.

xcr440 · Jan 6, 2009

the 260 or 026 works very well with a picco chain. I have that on my 026 it will cut just as fast as a 260 with a .325 chain.

MtnHermit · Jan 6, 2009

xcr440 said:
I difference is big on the drive sprocket. The measurement is from rivit to rivit .

That's equivalent to saying water runs downhill. In the link I provided, I'm sure the Stihl dealers know to provide the correct sprocket for different pitch chains.

BTW, it's rivet, not rivit. I believe frogs rivit, but don't hold me to that. Maybe only the Bud frogs.

MtnHermit · Jan 6, 2009

Thanks all, got my answer. Smaller pitch, smaller bite, faster chain speed. I'm learning.

PA Plumber · Jan 6, 2009

I do have an 026 set up with 3/8 - .050 - 7 T sprocket, and an 18" bar. Decent combo.

Does just fine, even buried in Black Oak. (The saw does have muffler mod.)

Recently acquired a roll of chain. It will be nice to have most of my saws set up the same.

HuskyMike · Jan 6, 2009

PlantBiologist said:
The 3/8" (.375) is a larger chain with a bigger cutter tooth and will take a larger bite of the wood. You need a larger saw to pull this chain, and it is the standard size on most saws over 55cc. Smaller saws do better with the .325, as it takes a smaller bite and therefore doesn't need as much power to pull.

How will that effect how the chain rides on the sprocket?

xcr440 · Jan 6, 2009

MtnHermit said:
That's equivalent to saying water runs downhill. In the link I provided, I'm sure the Stihl dealers know to provide the correct sprocket for different pitch chains.

BTW, it's rivet, not rivit. I believe frogs rivit, but don't hold me to that. Maybe only the Bud frogs.

yeah the dealers do but maybe the users don't.
Sorry I don't spell check before I hit enter. Didn't know the grammer police were on duty.

lambs · Jan 6, 2009

I've noticed my 029 super has the .325 pitch, with 1.6mm bar gauge. My Dad's 038 and 066 both run the 3/8" pitch, 1.3mm bar gauge. Anyone know why the heavier pitch chain has a smaller gauge?

mountainlake · Jan 7, 2009

MtnHermit said:
Just a little education, why do I care about subtle differences in chain pitch? If you look at the MS260 page one of the "Features" is the option of 325” or 3/8” pitch. Gee .325 or .375 would seem trivial.

Please explain.

Thanks

The main difference is chain speed 3/8 turns faster than 325 both with 7 tooth sprocket's. Stock 50cc saws don't have enough torque to pull a 3/8 in bigger wood(over 6" or so). My Husky 55 Rancher cut way faster in 12" oak when I switched from 3/8 to 325. They were both sharp chiesel, the kerf is just about the same on these 2 chains. I'd think a narrow kerf would really cut good but the cutters are so small it doesn't seem they would last long. Steve

tobster · Jan 7, 2009

mountainlake said:
The main difference is chain speed 3/8 turns faster than 325 both with 7 tooth sprocket's. Stock 50cc saws don't have enough torque to pull a 3/8 in bigger wood(over 6" or so). My Husky 55 Rancher cut way faster in 12" oak when I switched from 3/8 to 325. They were both sharp chiesel, the kerf is just about the same on these 2 chains. I'd think a narrow kerf would really cut good but the cutters are so small it doesn't seem they would last long. Steve

Why would 3/8 chain turn any faster than .325?

mountainlake · Jan 7, 2009

The links on 3/8 are farther apart makeing a 7 tooth sprocket a bigger diameter on 3/8 than 325, less torque is applied to the chain with 3/8, kind of like driving a 4 cylinder car up a steep hill in high gear, it won't make it, shift down and it will. Steve

Termite · Jan 7, 2009

My 5100 Dolmar came with 18".375. I tried 18".325 Woodland Pro chisel and it cuts better in hardwood.
Maybe someone could explain why, with the same diameter sprocket. That is same chain speed, .375 puts more load on the motor when the cutters are very close to the same width (.015" larger)and the same raker height. I know .375 will weigh more but that should not make much difference.

mountainlake · Jan 7, 2009

Termite said:
My 5100 Dolmar came with 18".375. I tried 18".325 Woodland Pro chisel and it cuts better in hardwood.
Maybe someone could explain why, with the same diameter sprocket. That is same chain speed, .375 puts more load on the motor when the cutters are very close to the same width (.015" larger)and the same raker height. I know .375 will weigh more but that should not make much difference.

A 325 8 pin is real close to 3/8 7 pin in chain speed and I'd think the 3/8 7 pin would put less load on the saw as there will be less teeth in the wood. We were talking about 325 7 pin compared to 3/8 7 pin. Steve

SawTroll · Jan 7, 2009

brages said:
.....
Wouldn't the fastest setup for a 260 be 0.325 narrow kerf? .....

That may very well be the case, but Stihl has never offered that option.

Carlton used to offer NK bars for Stihl, but I believe they quit a few years ago.

As I remember it, those bars got some bad "press", for being too wimpy/low quality. Oregon and Husky NK bars are quite good, but are not made with the Stihl mount.

brages · Jan 7, 2009

Termite said:
..[T]he cutters are very close to the same width (.015" larger)and the same raker height. I know .375 will weigh more but that should not make much difference.

Good question; I'd like to understand this too.

SawTroll · Jan 7, 2009

mountainlake said:
A 325 8 pin is real close to 3/8 7 pin in chain speed and I'd think the 3/8 7 pin would put less load on the saw as there will be less teeth in the wood. We were talking about 325 7 pin compared to 3/8 7 pin. Steve

Right - 8x.325 is just a tad larger than 7x3/8" - so more or less the same initial chain speed and torque on the chain.

.325 has more cutters as you say, but there are lots of other variables - so the load issue could go both ways.

Chain Pitch, What's the Difference?

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