RPM In The Cut

[Mastermind]

@Wanab have a look at the chainsaw dyno thread on here. Most of this has been covered in there. For a work saw like the 660 all it’s useable power comes in that 8-10k range.

I do my best to create a saw that has a pretty wide torque band. Peak power means something of course, but if it's all at 12k and gets pulled out of the power easily, it's pretty worthless as a real worksaw.

 

[davidwyby]

Rpm…pends on the variables…chain, sprocket, and how hard ya lever and stuff.

snelling had a video of cutting with the same saw 3 cuts pulling progressively harder in each, 1,000 rpm drop each. Don’t remember the cut times.


@Woodpecker not bad for OTB chain…

@huskihl dis bar too long too…didn’t get to try the picco yet@Mastermind wow on the 268, that is haulin’

 

[jakethesnake]

If your saw has excess rpm in the cut. I tend to lower my depth gauges a lil. Have some chains and bars that fit other saws but that other saw wouldn’t like the chain I have set for the other one

example 272 has 20” bar 72 drives
455 rancher. Same. Take the chain off the 272 rancher is gonna stall in cut.

I try to adjust my chains in wood big enough to bury the bar.

might be useful to some of you fellas asking

 

[Sawrain]

So a saw that's only dropping 1K is a good one, I would agree.

I would not think that to be the usual case.

Most of my saws are dropping around 3k in the wood, but this is of course up to me and my hands.

Outside of myself hopefully operating the saw at its optimal rpm, inherent to its design (and chain) it doesn’t really have a say in the matter, I could be Heavy handed and lug it to 8k or be light fingered and let it zing to 13k rpm.

On average, and using very general figures I would suggest that many stock saws tuned to ~13k rpm are being operated around 9.5k rpm, a full 3500rpm rpm drop.

Many saws would not be fully loaded at only 1000 rpm of load.

 

[jakethesnake]

I think the chain is gonna make all the difference in the world. There’s no way to answer this question in my mind. Obviously you want enough speed
I also don’t want a chain pulling or pushing me around.

I have a 272 with a long bar with high depth guages that I’ll bet doesn’t drop many rpms. But it cuts well. Same saw with a shorter more aggressive chain drops more rpms pulling that.

 

[Wonkydonkey]

I see you lads have been busy, since I went to lala-land last night.

 

[Mastermind]

@Mastermind wow on the 268, that is haulin’

Stump Shot actually built that saw.

 

[Finnrpm]

snelling had a video of cutting with the same saw 3 cuts pulling progressively harder in each, 1,000 rpm drop each. Don’t remember the cut times.

This one?

 

[Wilhelm]

It is amazing that the saw actually stayed put after he leaves her idling on top of the log.
Must be an engine with well balanced innards.

 

[jakethesnake]

Yeah all mine woulda wiggled off the log and down

 

[Lnk]

Yeah all mine woulda wiggled off the log and down

Set my 2094 on the ground idling yesterday to go get the screwdriver. Was five feet away from where I set it in 30 seconds. I must be doing something wrong.

 

[Wanab]

I would not think that to be the usual case.

Most of my saws are dropping around 3k in the wood, but this is of course up to me and my hands.

Outside of myself hopefully operating the saw at its optimal rpm, inherent to its design (and chain) it doesn’t really have a say in the matter, I could be Heavy handed and lug it to 8k or be light fingered and let it zing to 13k rpm.

On average, and using very general figures I would suggest that many stock saws tuned to ~13k rpm are being operated around 9.5k rpm, a full 3500rpm rpm drop.

Many saws would not be fully loaded at only 1000 rpm of load.

That has been my experience. The way I see it a saw has a sweet spot to run that is a combination of load and RPM where it cuts the fastest. That is also where I am looking to take my readings. I guess I am most interested in what causes certain saws not to loose RPM when others spin higher free RPM's then drop.

 

[huskihl]

That has been my experience. The way I see it a saw has a sweet spot to run that is a combination of load and RPM where it cuts the fastest. That is also where I am looking to take my readings. I guess I am most interest in what causes certain saws not to loose RPM when others spin higher free RPM's then drop.

Mostly due to improper or unbalanced port height, size, area, etc

 

[huskihl]

Retarded ignition timing can also allow unloaded over-rev followed by a bigger drop in rpm in the wood

 

[Wanab]

Mostly due to improper or unbalanced port height, size, area, etc

Kevin, would you agree the better saws drop less RPM in most cases?

 

[Mastermind]

Kevin, would you agree the better saws drop less RPM in most cases?

Would you agree that regardless of the saw, or the builder, with an overly aggressive chain, or a heavy hand, it can be pulled way....way down in the cut?

My point is simple. You're not allowing any variables to enter your ideal saw's dream world.

 

[Wanab]

Would you agree that regardless of the saw, or the builder, with an overly aggressive chain, or a heavy hand, it can be pulled way....way down in the cut?

My point is simple. You're not allowing any variables to enter your ideal saw's dream world.

Sure, but I don't run them like that. Not my ideal anything. I am just trying to understand what makes these things tick. My cutting style does not change between saws. Now sometimes I run more raker but not enough to kill the saw. It's pretty easy for me to dial them in. When you run the same bar and chain between saws that eliminates a great deal or variables.

 

[jakethesnake]

Sure, but I don't run them like that. Not my ideal anything. I am just trying to understand what makes these things tick. My cutting style does not change between saws. Now sometimes I run more raker but not enough to kill the saw. It's pretty easy for me to dial them in. When you run the same bar and chain between saws that eliminates a great deal or variables.

Even if you’re gentle with them. A self feeding chain that’s set aggressively will pull the saw down unless you hold up on the saw. I don’t pull on dogs much unless I’m starting to loose the edge on my chain.

 

[jakethesnake]

So still. It all depends On everything.

 

[jakethesnake]

Unless you have the same exact model of saw. Using the same chain is not ideal. If you tweak said chain. My long bar on my husky I mentioned hates new chain takes a few good sharpening sessions to give the depth guages the height I want. For that specific saw. Or occasionally you get the chain that’s set a touch high from the factory. Dunno why.

we overthinking again boys