8 pin rims

[HolmenTree]

Sean, I've heard alot of slang from the PNW and even out here, but you gotta take it with a grain of salt.
What loggers say to each other is like a communial language by saying shortcut slang.
What is understood in that circle could be totally misunderstood by some one else.

 

[HolmenTree]

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!

 

[SouthSoundTree-]

I could be wrong.

The context pointed to low/ filed-off rakers being what they were talking about.

I don't know if they use older chains on the landing for some reason, maybe due to poor/ dirty cutting conditions after skidding in logs. Smaller teeth get a bigger raker offset than larger.

If you can fell/ buck with smaller teeth with the normally greater raker offset, it seems like if you're only engaging a couple cutters at any one time, especially if the cutters are harder to keep razor sharp, that it could work on a landing.

I'll inquire with a former logger that I see a lot. He was a chaser, which if I understand right meant he worked on the landing. Gray beard.

The two guys I've heard about it from are 50 and 62. Maybe different chain designs, dunno.

Being softwood loggers, they may well have been using square filed chisel chain.


If the same chain is meant for all around use, it certainly needs to be closer to standard.

 

[squisher]

So Willard do you know say percentage wise what the speed difference between a seven and eight pin is? Because I will stand by my earlier statement that 8 pin rims seem to throw a chain harder when it does happen and I always attributed it to whatever speed difference there is. If there is no signifigant difference between the seven and eight pin why do they both exist? I've run both quite a bit. I've punctured tanks before, had it happen with a perfectly functioning catcher on it before too. If. You have bad luck the catcher can catch the chain and swing it right into the tank. If you have worse luck it swings a cutter right into it.

 

[squisher]

I've never heard of or wouldn't imagine it possible to run a chain with the rakers filed right off. I wouldn't see the point of it for limbing/bucking either?

 

[sotc]

I could be wrong.

The context pointed to low/ filed-off rakers being what they were talking about.

I don't know if they use older chains on the landing for some reason, maybe due to poor/ dirty cutting conditions after skidding in logs. Smaller teeth get a bigger raker offset than larger.

If you can fell/ buck with smaller teeth with the normally greater raker offset, it seems like if you're only engaging a couple cutters at any one time, especially if the cutters are harder to keep razor sharp, that it could work on a landing.

I'll inquire with a former logger that I see a lot. He was a chaser, which if I understand right meant he worked on the landing. Gray beard.

The two guys I've heard about it from are 50 and 62. Maybe different chain designs, dunno.

Being softwood loggers, they may well have been using square filed chisel chain.


If the same chain is meant for all around use, it certainly needs to be closer to standard.

Try it Sean, take one of your half used chains and an angle grinder. Hang on! IF you can cut i bet it'd be very inefficient, choppy and unsafe.

 

[squisher]

Yah most landing men/buckerman aren't going to favour an excessively low raker because it's rough as hell like Willie mentioned. It's going to make plunge cutting harder for bucking and it's going to do more damage when encountering rocks/dirt.

 

[HolmenTree]

So Willard do you know say percentage wise what the speed difference between a seven and eight pin is? Because I will stand by my earlier statement that 8 pin rims seem to throw a chain harder when it does happen and I always attributed it to whatever speed difference there is. If there is no signifigant difference between the seven and eight pin why do they both exist? I've run both quite a bit. I've punctured tanks before, had it happen with a perfectly functioning catcher on it before too. If. You have bad luck the catcher can catch the chain and swing it right into the tank. If you have worse luck it swings a cutter right into it.

As chain thrown with a 7 pin rim with more torque behind it can do more damage.
A 7 pin rim on a 562XP can have as much chain speed as a MS441 with a 8 and they both can do as much impact to the chain catcher.
I was on our logging camp's safety committee for 10 years doing monthly inspections of our cut and skid crews. As always missing badly damaged chain catchers showed how unsafe a saw can become.
Here's some 3/8" rims of mine.....7, 8, 9 and 13 pin.

 

[sotc]

from Madsens

The pitch (diameter) and tooth count of the sprocket determines how much chain is moved on each engine revolution. In fact, sprocket size is usually stated: Pitch "by" tooth count. An example is the size: 3/8" x 8. This describes a sprocket that is 3/8" pitch with 8 teeth. That means each time the crank shaft rotates, it will move eight drive links of a 3/8" pitch saw chain.

Since we promised no more math, we'll do a little for you: This means a saw turning 13,500 RPM fitted with a 3/8" x 8 tooth sprocket is moving chain at 75 mph. Another way of saying it is the chain is moving 110 ft in one second. Pretty amazing, huh

.
So if 110 FPS on an 8 then a 7 would be 96.25. So a 7 to 8 would be a 14.29% gain or an 8 to 7 would be a 12.5% loss

 

[SouthSoundTree-]

I don't run excessively low rakers. But would be willing to try it as an experiment.

If you don't push hard through the cut, with high chain speed, you may not rest on the rakers. There might be some technique to it that is different.

When delimbing, blowing through the cut asap avoids some binds, IME.

I've never worked a commercial landing. I was suspecting that they were bringing log length to the landing, so bucking wasn't an issue. Most limbs would be stripped by the feller/ bucker.

I figure that there shouldn't be that much regional difference between BC bush for Justin, and Oregon?? for Willie, from the people I talked to around here.

I'll investigate. Some time.

 

[sotc]

Yeah, I'd expect similar work conditions.
Generally when skidding tree length they will have a de-limber on the landing.

 

[SouthSoundTree-]

One guy that filed his rakers really low also wanted to climb with a chain and 3 biners (2 on one side, one to terminate) for a flip-line, like some palm climbers do, and used "lotta knots", repetitive overhands in place of a taut-line hitch or blake's hitch. Only for rappelling out after spurring up.

Old school. Maybe pre-delimber technique that has perpetuated like 'topping' trees.

Maybe its a bad logger technique.


Again, never worked a commercial landing, personally.


Coffee break is over, back to a report.

 

[HolmenTree]

from Madsens.
So if 110 FPS on an 8 then a 7 would be 96.25. So a 7 to 8 would be a 14.29% gain or an 8 to 7 would be a 12.5% loss

Thanks for sharing that Willie. Sam Madsen knew his math as he taught it for years at the local college. His OCD is a bit more severe then mine though lol.

 

[HolmenTree]

If you don't push hard through the cut, with high chain speed, you may not rest on the rakers. There might be some technique to it that is different.



I've never worked a commercial landing. I was suspecting that they were bringing log length to the landing, so bucking wasn't an issue. Most limbs would be stripped by the feller/ bucker.
.

It's impossible for the rakers (depth gauges ) to ride clear in the kerf no matter how light a feed pressure is applied. When the cutters bites in it automatically rocks back only stopping when the raker contacts the wood., then goes back level when it leaves the kerf.
You may have heard the term "porpoiseing" how a cutter cuts.

At our landings any limbs the faller misses the skidder operator will back blade off or run it off with the tire chains. In our extreme cold winter logging no limb survives staying on the logs by the time it gets to the landing.

 

[woodworkingboy]

Willie, I'm waiting for your calculations on gain and loss of torque when switching between a 7 and 8 pin. Please in the unit, newton metre, to help avoid ambiguity.

 

[squisher]

yes similar to Willie from what I've seen. I thought from what you were talking about Sean you meant cutting limbs which the odd one will need to be cut even though as Willard pointed out any skidderman worth his salt would've dealt with most anything that made it up from the hill. Still sometimes there's the odd one. Tree length or log length, seemed to me the buckerman still had to double check everything and make calls on the best way to process the log hence the bucking.

As for the torque of a seven pin causing a harder chain throw than the greater speed of a eight pin. I, through my own experience am not sold on that. I feel that torque difference applied to chain as it throws would be inconsequential compared to additional chain speed. It's the mass of the chain travelling at a higher rate of speed that has greater potential to do damage. It seems pretty straightforward to me, I'm sure someone smarter than me could right up a formula or something.

I was just originally adding the harder chain throw of the eight pin comment for people to consider as one of the factors when thinking about using one. I wasn't talking about comparing faster smaller saws with seven pins to slower bigger saws with eights. I was simply talking about the difference that I have experienced when changing from a seven to an eight on the same saw.

 

[sotc]

I'm working on that almost as hard as Sean is working on his report!

 

[squisher]

I'm counting on ya now!

 

[sotc]

Has anyone personally been issued by a thrown chain or actually know someone who has? Any time I've thrown a chain it ALWAYS comes off the drive and just slaps me, maybe all worry for no reality?

 

[squisher]

I've been cut mildly by one once. It came back and slapped me but through the crotch, luckily missing the jewels and gave me a ass slapping that would make a stripper blush.

I honestly have no idea the size of the rim I was running.

 

[treebilly]

I've had one when limbimg that managed to get past the chaps and slap me in the sack. Had to climb up in the truck and check on the boys. Just a bit of bruising, but sure as hell felt a lot worse
It was an 8 pin. For some reason we were dealt a bunch of saws that way

 

[HolmenTree]

I never have or know of anyone . I remember one of my old Jonsereds had a spur gear sprocket and it danced around for a bit but only damage done was to the drive links on the chain. (Think MS200)
By the time the chain hits the chain catcher it's pretty well free of the rim sprocket .

Worst derail I had was when I touched a tree with the bar tip of my 090 with a 5 foot bar at WOT.
I was holding the saw at bucking position, when the kickback happened the bar bent sideways throwing the chain. The saw completely jumped out of my hands.
Just to prove with a longer bar there's alot more leverage on the operators grip on the saw when a kickback happens then there is with a shorter b/c.

 

[flushcut]

Maybe the HP of the 090 had a small part in that kickback as well.

 

[HolmenTree]

Not alot more h.p. then my 395XP. But when all the heavy innards of that 090 are turning there's lots of inertia especially with that heavy clutch and that long .404 loop of chain turning. Plus the bar nose on that 5 foot bar was a 2 7/8" diameter roller.
I have a writeup somewhere in my collection where Oregon did a kickback test on different bar lengths, that was back in the early 1970s. They printed out a graph with all the bar lengths on the kickback machine with all their respective lb. per square inch forces. The longer the bar the more kickback energy they produced.

 

[sotc]

I've been cut mildly by one once. It came back and slapped me but through the crotch, luckily missing the jewels and gave me a ass slapping that would make a stripper blush.

I honestly have no idea the size of the rim I was running.

Hmmm, I see a gap my experience there.

I've had one when limbimg that managed to get past the chaps and slap me in the sack. Had to climb up in the truck and check on the boys. Just a bit of bruising, but sure as hell felt a lot worse
It was an 8 pin. For some reason we were dealt a bunch of saws that way

Toughen up man, where's the brass!