Changing from 3/8 lo pro spur to .325 rim sprocket - w/ hard nose

[Jameson]

Recently I saw some chatterings on this on a cs-400 so I took the plunge and went forward with the rim change.
I have opened up the muffler on my cs-400 and the spur sprocket is wearing from only a few cords of wood cut and a few stumps. The stock 18" bar nose sprocket did start to slow down on me - i sprayed with carb clean and penetrating oil - runs smoother now but wearing....

Oregon 513442

http://www.ebay.com/itm/110816218288?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Which is .325 rim sprocket.

Lets say this fits, am I out of line to use this bar - a 16" sugi hardnose and a .325 round chisel chain? Tell me about Narrow kerf?

The hardnose bar fits, but on the spur sprocket with the 3/8 lo pro 91vxl with 57 drivelinks wasn't long enough.


What link length? and chain to fit this hardnose bar. I picked up a 20lpx066g and crossing my fingers it fits well.

I cut dirty firewood.


https://www.dropbox.com/s/0yv14t8rzkuushj/2014-11-03 23.29.49.jpg?dl=0

 

[Jameson]

Pk

 

[Jameson]

?

 

[sunfish]

The hard nose bar will work fine, just don't run the chain as tight as you would on a sprocket tip bar.
Can't help with the other questions.

 

[SawTroll]

LPX is excellent chain - but it is chisel chain, that isn't very suitable for dirty wood.

We need to know more about the bar to really say anything about the gauge and dl counts that will fit.....

Also, I suspect that you would be better off with a 3/8" Picco/lo-pro chain on that saw.

 

[Jameson]

Oh the bar is 50 gauge. If I could find a lo pro rim sprocket I would stick with lo pro

 

[Franny K]

Narrow kerf .325 chain has cutters just a tiny bit bigger than the biggest 3/8 lo pro on a lighter duty pivot pins and side plates than normal .325.

The ratio of "3/8" to .325 is real close to 8 to 9. You can figure out the lengths use .367 for the lenght of the 3/8 not .375 and two increments per drive link. a .325 "15" inch loop of 64 drivers is a bit longer than a "16" inch 56 driver lo pro.

 

[SawTroll]

Oh the bar is 50 gauge. If I could find a lo pro rim sprocket I would stick with lo pro

That will not happen, unless you find costum made "pin-type# sprockets. They have been made by Danzco at least, but were no longer listed the last time I checked.

 

[Franny K]

I suspect you would find the standard 3/8 7 tooth small spline rim sprocket and the low pro chain will be better than the .325nk or .325lpx on that saw. Not sure exactly how much larger a 3/8 lo pro 7 tooth should be than the standard 3/8 probbably around 0.040" I have been using one from left coast supply a GB branded one which must have been never finished as it is about 0.010 larger in diameter but the outside isn't concentric with the inside. The effective diameter of a spur sprocket gets smaller with use.

If you hit your dirt occasionally in big globs that will dull any chain the smaller lo pro cutters have significantly less material to file.

 

[cobey]

Recently I saw some chatterings on this on a cs-400 so I took the plunge and went forward with the rim change.
I have opened up the muffler on my cs-400 and the spur sprocket is wearing from only a few cords of wood cut and a few stumps. The stock 18" bar nose sprocket did start to slow down on me - i sprayed with carb clean and penetrating oil - runs smoother now but wearing....

Oregon 513442

http://www.ebay.com/itm/110816218288?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Which is .325 rim sprocket.

Lets say this fits, am I out of line to use this bar - a 16" sugi hardnose and a .325 round chisel chain? Tell me about Narrow kerf?

The hardnose bar fits, but on the spur sprocket with the 3/8 lo pro 91vxl with 57 drivelinks wasn't long enough.


What link length? and chain to fit this hardnose bar. I picked up a 20lpx066g and crossing my fingers it fits well.

I cut dirty firewood.


https://www.dropbox.com/s/0yv14t8rzkuushj/2014-11-03 23.29.49.jpg?dl=0

it should take at least 66 dl of .325 you should be able to run lo pro also probably 60 + drivers

 

[cobey]

LPX is excellent chain - but it is chisel chain, that isn't very suitable for dirty wood.

We need to know more about the bar to really say anything about the gauge and dl counts that will fit.....

Also, I suspect that you would be better off with a 3/8" Picco/lo-pro chain on that saw.

bpx is the semi chisel chain

 

[cobey]

hope its a 7 pin rim.. that will help it pull harder

 

[SawTroll]

bpx is the semi chisel chain

Yes - but going with 95VPX/H30 (narrow kerf) makes more sense on that saw.

 

[Jameson]

Parts came in, going to set her up and see.......

I was also thinking of the narrow kerf stuff.

My logic is that the husky 440e can handle .325 so my echo can as well!

Still thinking about a cs-590 to round out the collection.

 

[mountainlake]

You'll slow down your cutting speed with the .325. Steve

 

[Franny K]

I will predict the hard nose bar makes significant heat and isn't a good choice for firewood duty whatever that means. I have one of those bars in "14" inch it takes 60 drive links of .325 and calls for 53 of 3/8 but 52 can be forced on in most cases. They do make more heat than the bigger radius nose like oregon laser plus medium nose, more comparable to the laser lite.

 

[SawTroll]

I will predict the hard nose bar makes significant heat and isn't a good choice for firewood duty whatever that means. I have one of those bars in "14" inch it takes 60 drive links of .325 and calls for 53 of 3/8 but 52 can be forced on in most cases. They do make more heat than the bigger radius nose like oregon laser plus medium nose, more comparable to the laser lite.

Hard nose bars also rob from the already limited power of that small saw - generally a bad idea.

 

[BBP]

I keep reading that people should stick with the smaller size chains for various saws. Why is this? I understand that a saw may not have enough power to pull a larger size cutter, but if the smaller cutters work better, why ever go to a larger one if it eats more power? What are the circumstances that would make 3/8 work better than .325 & why? For instance, why does a 60cc saw come with 3/8 instead of .325? What's the advantage?

 

[SawTroll]

I keep reading that people should stick with the smaller size chains for various saws. Why is this? I understand that a saw may not have enough power to pull a larger size cutter, but if the smaller cutters work better, why ever go to a larger one if it eats more power? What are the circumstances that would make 3/8 work better than .325 & why? For instance, why does a 60cc saw come with 3/8 instead of .325? What's the advantage?

The sprocket size/gearing that is availiable is an important factor, not only the size of the cutters.

Btw, it isn't obvious that 3/8" will cut faster than .325 on a 60cc saw - a lot of it has to do with how the gearing matches the power of the saw and the task at hand.

 

[BBP]

The sprocket size/gearing that is availiable is an important factor, not only the size of the cutters.

Btw, it isn't obvious that 3/8" will cut faster than .325 on a 60cc saw - a lot of it has to do with how the gearing matches the power of the saw and the task at hand.

Maybe a better way to ask the question would be, what are the circumstances that would make going to a wider kerf be advantageous & why? Why not use the narrowest kerf available & gear it up according to power output. If going to a wider kerf eats more power, why do it on any saw regardless of power? What dictates the change to a wider cutter?