DanManofStihl
ArboristSite Guru
I have a 066mag and I run a 20 inch bar 3/8 s pitch 50 guage should I use a 7 or 8 pin sprocket thanks for the help
7 or 8 pin sprocket
- Thread starter DanManofStihl
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Crofter
Addicted to ArboristSite
066 can definitely handle 8 pin with that bar length.
chainsawworld
ArboristSite Guru
if you are going to run that short of a bar on that saw have you thought about a 9 pin?
Stumper
One Man Band
8
8
8
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8
WoodTick007
Addicted to ArboristSite
Why don't you order a 10 pin gear from Madsens? Remember SpeedKills.
Basically, the smaller sprockets (seven tooth) will give your saw the most cutting power. Use these on small saws that are running long bars. For example: A STIHL 044 with a 32" bar works best with a 3/8 X 7 sprocket. A big saw with a long bar also benefits from a seven tooth sprocket. For example : A HUSKY 3120 with a 50" bar works best with a 404 X 7 sprocket.
When saws have plenty of power for the bar they are running, or the operator desires chain speed at the expense of power, the larger sprockets work best. The larger sprockets (eight tooth) have a larger diameter than their smaller brothers. This large sprocket works like a large gear. When the crankshaft rotates one turn, the larger sprocket moves more chain than the smaller one. The eight tooth sprocket has the same effect as a high gear ratio rear end has in a truck - the speed is great, but you better have plenty of horsepower when you come to a hill.
Sprocket Size Affects Chain Derailure
One effect most saw operators don't think about is the tendency for large sprockets to increase the possibility of chain derailure, or "throwing" chains, as most timber cutters call it. A large diameter sprocket, used on a saw running a bar with a narrow heel, will make a combination that throws chains frequently. The reason is: The height of the sprocket may hold the chain out of the bar rails for a long distance on the heel. When the chain is running "unguided" for a distance on the heel, the sideways force of a bound limb being cut may cause the chain to throw. This is aggravating and dangerous.
To remedy this situation, select bars that have a wider heel when running large sprockets. This usually means new bars will work better than bars with worn heels. Also, run chains as short as possible. Running a short chain will cause the heel of the bar to sit very close to the sprocket. This will usually reduce the chains "unguided" distance.
sprocket Size & Tooth Count
One last comment on sprocket size: The diameter of a 3/8 X 8 sprocket is very close to the diameter of a 404 X 7 sprocket. This occurs because the 3/8 is a smaller pitch, so in spite of its extra "tooth," it is about the same size. If you are switching to 3/8 chain, from 404, use the 3/8 X 8 sprocket if you want about the same "gearing" as you had with the 404 X 7. Another example explains why 3/8 X 7 sprockets work well on small pro saws. These saws not only benefit from 3/8 chain (which is lighter and more flexible than 404), but the 3/8 X 7 sprocket is the smallest diameter of all sprockets. This gives these small pro saws low "gearing" and enables them to run fairly long bars.
Basically, the smaller sprockets (seven tooth) will give your saw the most cutting power. Use these on small saws that are running long bars. For example: A STIHL 044 with a 32" bar works best with a 3/8 X 7 sprocket. A big saw with a long bar also benefits from a seven tooth sprocket. For example : A HUSKY 3120 with a 50" bar works best with a 404 X 7 sprocket.
When saws have plenty of power for the bar they are running, or the operator desires chain speed at the expense of power, the larger sprockets work best. The larger sprockets (eight tooth) have a larger diameter than their smaller brothers. This large sprocket works like a large gear. When the crankshaft rotates one turn, the larger sprocket moves more chain than the smaller one. The eight tooth sprocket has the same effect as a high gear ratio rear end has in a truck - the speed is great, but you better have plenty of horsepower when you come to a hill.
Sprocket Size Affects Chain Derailure
One effect most saw operators don't think about is the tendency for large sprockets to increase the possibility of chain derailure, or "throwing" chains, as most timber cutters call it. A large diameter sprocket, used on a saw running a bar with a narrow heel, will make a combination that throws chains frequently. The reason is: The height of the sprocket may hold the chain out of the bar rails for a long distance on the heel. When the chain is running "unguided" for a distance on the heel, the sideways force of a bound limb being cut may cause the chain to throw. This is aggravating and dangerous.
To remedy this situation, select bars that have a wider heel when running large sprockets. This usually means new bars will work better than bars with worn heels. Also, run chains as short as possible. Running a short chain will cause the heel of the bar to sit very close to the sprocket. This will usually reduce the chains "unguided" distance.
sprocket Size & Tooth Count
One last comment on sprocket size: The diameter of a 3/8 X 8 sprocket is very close to the diameter of a 404 X 7 sprocket. This occurs because the 3/8 is a smaller pitch, so in spite of its extra "tooth," it is about the same size. If you are switching to 3/8 chain, from 404, use the 3/8 X 8 sprocket if you want about the same "gearing" as you had with the 404 X 7. Another example explains why 3/8 X 7 sprockets work well on small pro saws. These saws not only benefit from 3/8 chain (which is lighter and more flexible than 404), but the 3/8 X 7 sprocket is the smallest diameter of all sprockets. This gives these small pro saws low "gearing" and enables them to run fairly long bars.
MacDaddy
Addicted to ArboristSite
8,9 or maybe even a 10 with the small bar
tony marks
Addicted to ArboristSite
8 pin easy for that setup.. jmo
but id consider woodticks comments about safety..hadnt thought about that to much..
but id consider woodticks comments about safety..hadnt thought about that to much..
Steve here... 8 pin... leave the 9 and ten pin to the old beasts that have the torque to pull a big wheel but need the chain speed....
Is anyone aware of what bar brand has the widest heal? When using a 8 pin, 20" bar combo on a 7900 the saw doesnt oil right unless you run a 73 link chain due to the heal being too narrow and the chain riding out of the groove in oilers discharge area. bTW this doesthis with oregon and Winsdor bars? The saw works fine with a 24" GB and a 8 pin.
Hay Ben I just purchased a 24" Windsor bar, the holes line up, and the chain picks up the oil just fine when I use an 8 pin. I think they fixed the problem with the newer bars.
Crofter
Addicted to ArboristSite
On some bars they build in an oil dam in the bottom of the groove between the oil hole and the rear of the bar. Overall the groove is much deeper than the drive tang length, but in this area it rises up to just kiss the bottom of the tangs. This helps prevent to oil from running back downhill off the heel of the bar. This dam is soft and wears down as the guide rails on the rear of the bar wear, to maintain the relationship. Going to a larger sprocket will pick the chain up slightly and cause more oil to be lost. It might be worse with a well worn bar than a new one.
Andy, the bars i reffered to earlier where both new within the lastfew months. Does your Windsor say made in Canada on it?
Yes it's made in Canada.
pbtree
Addicted to ArboristSite
8 pin - JMO...
chainsawworld
ArboristSite Guru
when i mentioned the 9 pin i just wanted to open the field a little more. in the woods i would not recommend it. in competition i run the 9 pin on the shorter bars with full skip-full chisel chain. i can work the cutters more and still maintain chain speed. i just started this this year so i am still playing with it. this new combination seems to be doing well. the saw(066 digital mag.) is winning. (stock saw classes)
i do run the 7 tooth on the longer bars on the larger saws with full skip in the woods for bucking the big stuff. shorter bars of coarse get the 8 tooth.
it may not hurt to do some time runs with your saws. see which one your saw likes better for your application. i had a solo 667 with a 20" bar and chain. in 8x8 spruce with the 7 tooth rim, the saw timed 2.06,2.09,2.06. with an 8 tooth, the saw timed 2.59,2.67,2.69. the only change i made was the rims. this is not a big deal for joe home-owner. differant species and size of the wood will change things also.
remember too, the faster the chain speed the faster dirt and rocks work, to take the edge off.
marty
i do run the 7 tooth on the longer bars on the larger saws with full skip in the woods for bucking the big stuff. shorter bars of coarse get the 8 tooth.
it may not hurt to do some time runs with your saws. see which one your saw likes better for your application. i had a solo 667 with a 20" bar and chain. in 8x8 spruce with the 7 tooth rim, the saw timed 2.06,2.09,2.06. with an 8 tooth, the saw timed 2.59,2.67,2.69. the only change i made was the rims. this is not a big deal for joe home-owner. differant species and size of the wood will change things also.
remember too, the faster the chain speed the faster dirt and rocks work, to take the edge off.
marty
Like an 044 works well at all with a 32" bar... What are you cutting; balsa?WoodTick007 said:
You quoted a bunch of stuff off Madsens website, right?
Have you <i>ever</i> had a thrown chain that didn't occur because the chain was flipped off the bar tip by sideways contact on a loose chain just as it was about to go from the top of the bar over the nose?
I'd say the biggest problem you'd encounter would be the possibility of inadequate oil retention, as Bwalker mentioned, <i>if you're using Oregon bars</i> on that Stihl saw.
The 066 comes with 3/8-8 and that should be used for every bar length you've got. Don't forget that for the 25" and 28" bars (at least) one extra drive link is called-for.
Glen
MacDaddy
Addicted to ArboristSite
I run a 8 on all my work saws and most run a 32 inch bar with full comp this is also soft wood like pine and fur But I cut wood that is about 30 inch and bigger my 372 will pull a 8 pin great in this type of wood I use a 8 pin when I mill wood also on a 385xp it pulls it great My point is make your chain work with your saw not your saw to work with your chain ALL SAWS CUT GOOD WITH THE RIGHT CHAIN
sprocket
Doubt the sprocket is a factor with stock size rims.
Once you go above that, it is a factor. That is why we make the back of the bar wider.
Doubt the sprocket is a factor with stock size rims.
Once you go above that, it is a factor. That is why we make the back of the bar wider.
Al Smith
Addicted to ArboristSite
32" bar
On me 042 Stihl,I normally run a 20",with an 8 tooth.It will,pull a 32",with a 7 tooth,in Oak,not balsa.It,of course,doesn't have the power of my 048s,but does ok.Incidently it's a Gb bar,the saws don't seem to be offended by it.
On me 042 Stihl,I normally run a 20",with an 8 tooth.It will,pull a 32",with a 7 tooth,in Oak,not balsa.It,of course,doesn't have the power of my 048s,but does ok.Incidently it's a Gb bar,the saws don't seem to be offended by it.
