Trying to find 6 tooth sprockets for stihl

[over9k]

Here lies your answer. It doesn’t exist because it can’t be made to work. The MS170 is so underpowered it needs the 6T spur. Interestingly enough, some spur sprockets are interchangeable between models, but I don’t think a 170 and 391 are. A 170 6T spur actually fits only an 026, I only know this because I bought a used one that came that way.

Surely if a picco can be made in 6 tooth then a regular 063 gauge chain can?

And as an extension, surely if a spur sprocket can be made in a 6 tooth then a rim sprocket can be?

 

[SAWMIKAZE]

Ok. What about 6 tooth spur for the 391?

Negative.

Buy a saw with balls if you can.

 

[MagraAdam]

Torque. I am cutting dry australian hardwood which is unbelievably hard/dense. As far as I know, it's the hardest/densest wood in the world.

Hey mate, I'm down in Tassie and cut tons of wood for my heating. Don't listen to the people telling you that you need a bigger saw. I ran the 391 and 170 combo for ages and it worked a treat. I've changed to a 361 (slightly more power and lighter than the 391) and a 250 (slightly heavier than a 170 but a ton more power) an the 391 with a 20 inch full chisel 3/8 063 chain kept sharp and the saw tuned well (rich) did me really well. The 170 has a 3/8p 053 14 inch full chisel chain and was great for limbing. Both set up with better dogs. I like a wider chain because it means there is lots of room for the bar and it's easier to cut. Get a progressive raker guide and sharpen by hand and that saw will be enough for most jobs. I've been bar deep in massive wood and never had a problem. Get the most out of what you own I say..

If money wasn't an option, I'd own a 151t, a 261, a 462, and that would do everything I need to do.

 

[user 122190]

Hey mate, I'm down in Tassie and cut tons of wood for my heating. Don't listen to the people telling you that you need a bigger saw. I ran the 391 and 170 combo for ages and it worked a treat. I've changed to a 361 (slightly more power and lighter than the 391) and a 250 (slightly heavier than a 170 but a ton more power) an the 391 with a 20 inch full chisel 3/8 063 chain kept sharp and the saw tuned well (rich) did me really well. The 170 has a 3/8p 053 14 inch full chisel chain and was great for limbing. Both set up with better dogs. I like a wider chain because it means there is lots of room for the bar and it's easier to cut. Get a progressive raker guide and sharpen by hand and that saw will be enough for most jobs. I've been bar deep in massive wood and never had a problem. Get the most out of what you own I say..

If money wasn't an option, I'd own a 151t, a 261, a 462, and that would do everything I need to do.

A two man crosscut saw also works. And remember to bring the mule....

 

[sean donato]

Hey mate, I'm down in Tassie and cut tons of wood for my heating. Don't listen to the people telling you that you need a bigger saw. I ran the 391 and 170 combo for ages and it worked a treat. I've changed to a 361 (slightly more power and lighter than the 391) and a 250 (slightly heavier than a 170 but a ton more power) an the 391 with a 20 inch full chisel 3/8 063 chain kept sharp and the saw tuned well (rich) did me really well. The 170 has a 3/8p 053 14 inch full chisel chain and was great for limbing. Both set up with better dogs. I like a wider chain because it means there is lots of room for the bar and it's easier to cut. Get a progressive raker guide and sharpen by hand and that saw will be enough for most jobs. I've been bar deep in massive wood and never had a problem. Get the most out of what you own I say..

If money wasn't an option, I'd own a 151t, a 261, a 462, and that would do everything I need to do.

So you also swapped out to smaller sprockets? I honestly don't see the point. You have to work within the saws limits. Skip tooth will be your friend on small under powered saws. No need to reinvent the wheel. (In this case sprocket) the smaller rims will negatively effect cut time and possibly give way to more kick back. (As the saw will be able to exert more force on the chain if it grabs) I wouldn't run out and replace them, just accept their limits. If it becomes grossly apparent that the saws are not in their happy places I would consider a good used pro model saw. Of your not sawing often then I'd just deal with what I had till I blew one of them up. It's taken me years to get all the saws I have and truthfully only really use 3 of them regularly. I have been through several home owner grade saws and learned my lesson with them. I'll never get one again, they don't last for long and don't preform anywhere close to a pro model.

 

[Ryan'smilling]

Surely if a picco can be made in 6 tooth then a regular 063 gauge chain can?

And as an extension, surely if a spur sprocket can be made in a 6 tooth then a rim sprocket can be?

You need to look at how a spur sprocket and rim sprocket are made. The spur is basically machined down from a nub (or maybe it's cast). The center bit can be very small. And so, they can be made small enough to fit only 6 teeth. When you consider a rim though, the drum must have a splined shaft strong enough to transfer the power from the crank to the chain. Also the rim must be that strong. The rim must fit around the splined shaft. It just can't be made small enough in diameter to run 6 teeth.

Another example of this is the Stihl 036. Originally it used the mini spline drums and rims from stihl, and you can use a 7t .325 rim. However, the bearing under the drum was prone to failure, so they have a kit to upgrade that bearing size. Because the bearing is bigger though, you need to use the large spline drums and rims. And now, if you want to run .325, the smallest rim available is 9t. It's really very simple.

 

[over9k]

You need to look at how a spur sprocket and rim sprocket are made. The spur is basically machined down from a nub (or maybe it's cast). The center bit can be very small. And so, they can be made small enough to fit only 6 teeth. When you consider a rim though, the drum must have a splined shaft strong enough to transfer the power from the crank to the chain. Also the rim must be that strong. The rim must fit around the splined shaft. It just can't be made small enough in diameter to run 6 teeth.

Another example of this is the Stihl 036. Originally it used the mini spline drums and rims from stihl, and you can use a 7t .325 rim. However, the bearing under the drum was prone to failure, so they have a kit to upgrade that bearing size. Because the bearing is bigger though, you need to use the large spline drums and rims. And now, if you want to run .325, the smallest rim available is 9t. It's really very simple.

Understood. Surely if a picco can be made as a 6t spur then a regular 063 3/8 chain can be too though?

 

[Ryan'smilling]

Understood. Surely if a picco can be made as a 6t spur then a regular 063 3/8 chain can be too though?

I wouldn't know. Maybe, maybe not. Part of the equation is that saws that run full sized 3/8 pitch chain are likely to run bigger clutch drum bearings, which limits the possibilities. Another part of the equation is that I doubt there is much demand for such a spur, so that too will limit the chance of its existence.

 

[MagraAdam]

So you also swapped out to smaller sprockets? I honestly don't see the point. You have to work within the saws limits. Skip tooth will be your friend on small under powered saws. No need to reinvent the wheel. (In this case sprocket) the smaller rims will negatively effect cut time and possibly give way to more kick back. (As the saw will be able to exert more force on the chain if it grabs) I wouldn't run out and replace them, just accept their limits. If it becomes grossly apparent that the saws are not in their happy places I would consider a good used pro model saw. Of your not sawing often then I'd just deal with what I had till I blew one of them up. It's taken me years to get all the saws I have and truthfully only really use 3 of them regularly. I have been through several home owner grade saws and learned my lesson with them. I'll never get one again, they don't last for long and don't preform anywhere close to a pro model.

No, stock sprockets for me. Agree that 7 on the 391 is a good mix of speed and torque.

 

[J D]

Understood. Surely if a picco can be made as a 6t spur then a regular 063 3/8 chain can be too though?

 

[Brushwacker]

A 7 tooth .325 on the 391 would lower your gear ratio significantly and your fuel mileage would drop I expect cause it has for me when i done it. If you need the power with that saw it might be worth a try. I have had skip .325 chain from Bailey's in the past which in your case it might be your best option if you can find it. I think most the manufacturers don't make it but it does or at least did.