8 pin rims

[flushcut]

Anybody using one in hardwoods? And on what saw?

 

[Reddog]

Assuming you are asking for 3/8 pitch chain.

390xp, 88cc, full skip and semi skip chain. 24", 28" bars.

Also used a 8pin on the 441 I use to have.

 

[stig]

MS 441, Ms 461.
But then i only run an 18" bar on those saws.
Stricktly for limbing big ones and felling smaller stuff.

Works wonderfully, assuming one can file really well.

My apprentice used my saw last week for the first time, and got a total WTF moment about how fast it cut.

We don't let apprentices run 8 pin till they can sharpen and handle a saw well.

 

[Dave Shepard]

395 XP.

 

[SouthSoundTree-]

Rajan, what is you underlying reason for inquiry?


To me, who isn't a super saw person, its less about species and which saw, as it is proof in the pudding. Depends on how much resistance compares to power. You'll pick up chain speed at the reduction of torque. If you still have all the torque you need to power though without bogging the saw down, keeping an elevated chain speed over 7 pin, you're in like Flynn. Just seems situational.




I'll run an 8 pin sprocket on a modded 460 with a 20" bar in soft wood or hardwood (most of our hardwoods are softer than average).

 

[flushcut]

I am just asking on more of an academic note. My 3120 is a bit slow but has all the torque one could ever ask for and I have a lot of stumps to grind in spring and alap so I just wanted to pick up a bit more speed. Mostly ash, a few oaks, and even fewer other varieties.
36" and 42" bars

 

[HolmenTree]

8 pin will give your 3120 more chain speed but lowering big hardwood stumps I don't see any advantage.
My 395XP -32" came from the factory with a 7 pin 3/8". I tried the 8 pin for lowering stumps but quickly went back to the 7. Torque rules in this type of cutting .
Here's a video my 12 yrs old daughter and I put together a few months ago. I timed 8 and 7 pin .325 rims on my 562XP bucking a 9X9" spruce. The 7 pin rim won.

http://youtu.be/ROLWSJWyJwQ

 

[SouthSoundTree-]

Big cuts with bad grain/ chain interaction probably needs all the available torque, even with that size saw.

 

[Ed L]

My 066 had a 8 pin sprocket & 20" bar, since it's used for felling & stumping I switched it to a 7 pin & 24" bar. After I got a 36" bar for it, no way was the 8 pin going back on.

Ed

 

[flushcut]

I think I'll stick with a 7 pin.

 

[woodworkingboy]

Never ran an eight pin, I don't think. I've got an 034 that i put an 036 jug and piston onto that I fully modded. Super high torque very powerful saw and it's always been a solid runner through hard use. A bit scary when I first started to use it. I love the thing. It seems like a good candidate for an eight pin sprocket, always had it in mind to change over if I could find one. Dealers don't seem to carry them in these parts.

 

[squisher]

Imo that greater chain speed can really increase the chance of a chain throw, while say limbing or brushing of any sort. As well that increased chain speed causes chain throws to be more violent and damaging.

 

[stig]

Which is one reason I don't let apprentices run 8 pin till they have proven themselves capable.

 

[sotc]

I dug out an 8 pin yesterday and slapped it on the 660 for firewood cutting, I dig it. Also realized I had a .404 rim on it and 3/8 chain. Not sure how that happened

 

[HolmenTree]

Even with higher powered modified saws a 8 pin rim is of no advantage unless you're running square ground chisel chain in a speed bucking competition. Round filed chain takes more power to pull and that's where the lower gear ratio 7 pin comes in....no matter if your running a 18" or 36" b/c.
Chain derailing with a 8 pin? Good way to teach the operator proper chain tension . But I do find with the larger diameter rim that a chain's chassis (links) stay in better shape alot longer and easier on the rails at the tail of the bar.
8 pin 3/8 rims basically went out with the old school saws with limited top end rpm like the old Jonsereds 621 and 801 for example.

 

[sotc]

Went out? Of fashion?

 

[squisher]

Proper tension, cutting technique, alignment of the sun and moon, and whatnot. Anyone that runs a saw everyday is going to throw a chain sooner or later. Was just saying that the increased chain speed equates to more potential for damage when it happens.

7 or 8 pin 3/8 rims are readily available at my local saw shop.

 

[SouthSoundTree-]

I've never timed it, but 3-4" cuts don't seem like they'd eat up the available torque. Just have to use the appropriate pressure. Dunno. For 'bumping knots' on a logging landing, I hear that they don't even use rakers. Can't buck for snot, obviously.

Hard to replicate limbing compared to cant cutting.

 

[flushcut]

Fashion? No, they make awesome necklaces for the bling savvy cutter. lol

 

[HolmenTree]

Proper tension, cutting technique, alignment of the sun and moon, and whatnot. Anyone that runs a saw everyday is going to throw a chain sooner or later. Was just saying that the increased chain speed equates to more potential for damage when it happens.

7 or 8 pin 3/8 rims are readily available at my local saw shop.

The increased chain speed of a 8 pin over a 7 is not significantly enough speed for more potential damage.
Where the potential damage comes from is from not replacing the aluminum chain catcher when it finally gets cut off completely.
There was a time when Stihl realized they had to put a aluminum guard on the front bottom corner of the gas tank because operators weren't replacing the chain catcher.
Chain tension is something I grew up with , yeah sure I have derailed alot of chain limbing spruce with a 7 pin too.

 

[HolmenTree]

For 'bumping knots' on a logging landing, I hear that they don't even use rakers.
.

LOL, you don't seriously believe that do you?

 

[HolmenTree]

8 pin 3/8 rims basically went out with the old school saws with limited top end rpm like the old Jonsereds 621 and 801 for example.

Went out? Of fashion?

You were still pissing in a diaper when those saws went out

 

[sotc]

. For 'bumping knots' on a logging landing, I hear that they don't even use rakers.

Maybe some knot head, never seen or heard of that myself. That would be completely unusable.

 

[SouthSoundTree-]

LOL, you don't seriously believe that do you?

I have heard it independently from people that have worked landings. I do believe it might work for that task alone. I worked with him for over two years at SPs. He had a guy working under him before that who wanted to run with no/ low rakers, but obviously couldn't buck or bore for snot.

The guy who just worked for me didn't understand raker gauges. He could file it sharp as snot, but wanted the rakers too low, meaning I couldnt' cut with the tip well or bore-cut. He came out of logging.

They file the rakers way down, possibly not all the way off, but custom for bumping knots on the landing, way low, from what I'm told.

 

[sotc]

You were still pissing in a diaper when those saws went out

I've never been known to be fashionable, even when in diapers.I've a little drawer full of those unfashionable things
Heck, every time Murph drops a tree I chocolate my britches!