Testing 8 9 10pin sprockets on Cannon belly bar, Cannon SBP, Tsumura

[Chainsaw Jim]

Here's a good reason why a rounded belly will have faster chain cutting speed..
See how the raker depth changes and gets taller to accommodate the larger sprocket as they go from flat to rounded:

You'll also notice the angle of the cutters changing.

 

[Termitebuffet]

damn dude. you sure are a fckin prick !

Wendell's the prick ...T1 is the arsehole......[emoji13]

Zoo City Sawz

 

[Brush Ape]

Wendell's the prick ...T1 is the arsehole......

I always wondered which one was the boar and which one was the sow.

 

[Deets066]

Here's a good reason why a rounded belly will have faster chain cutting speed..
See how the raker depth changes and gets taller to accommodate the larger sprocket as they go from flat to rounded:View attachment 41455 View attachment 41456

You'll also notice the angle of the cutters changing.

Doesn't the depth go the opposite way on the other side of the belly

 

[Definitive Dave]

$10k to figure out less friction is better? Way to go.

Dude!! I know damn well you can express a difference of opinion in a manner that doesn't come off like all agro for that sake of agro itself.
Julian loves to experiment and adds value and interest to this forum.
If you have ideas to add, even in direct opposition to others posted, try to be half-assed civil.
I have never seen Redbull661 post anything even slightly off-color or untoward in the past.
Seems like he is a deliberate target for you for some reason.
Dave

 

[Definitive Dave]

Here's a good reason why a rounded belly will have faster chain cutting speed..
See how the raker depth changes and gets taller to accommodate the larger sprocket as they go from flat to rounded:View attachment 41455 View attachment 41456
You'll also notice the angle of the cutters changing.

Doesn't the depth go the opposite way on the other side of the belly

dammit now I have to lay a straight edge on both sides, you are an evil man Deets

 

[Philbert]

Here's a good reason why a rounded belly will have faster chain cutting speed.

I can accept why the round belly would be an advantage. The shape also follows the centrifugal path of the chain, as opposed to trying to flatten out the loop in motion. My question is why the incremental change in sprocket diameter / tooth count seems to follow the opposite cutting speed progression on one bar, compared to the other two.

Philbert

 

[Brush Ape]

. Does anyone here, actually have ANY background in physics?!?!?

Well I've listened to Physical Graffiti backward is that what you mean?

 

[Keith Gandy]

Dude!! I know damn well you can express a difference of opinion in a manner that doesn't come off like all agro for that sake of agro itself.
Julian loves to experiment and adds value and interest to this forum.
If you have ideas to add, even in direct opposition to others posted, try to be half-assed civil.
I have never seen Redbull661 post anything even slightly off-color or untoward in the past.
Seems like he is a deliberate target for you for some reason.
Dave

Whole site has been wacky lately

 

[Definitive Dave]

Correct me if I am wrong but a saw has torque and the combination of saw, sprocket, bar and chain have cutting speed.
I see people say that such and saw combo doesnt have as much torque as another, but isnt that an inaccurate way of at least phrasing it.

In other words if the same power head bar and chain cut at a different speed with a 8 pin vs a 9 pin the torque didnt change did it?
Maybe I am up too late to think clearly.
When I am trying to find the fastest setup I swap out everything till I get the best combo but I never considered it to have the best torque just the best speed.

 

[Chainsaw Jim]

My question is why the incremental change in sprocket diameter / tooth count seems to follow the opposite cutting speed progression on one bar, compared to the other two.

Philbert

When the rakers are taller there is less resistance on the cutters allowing a larger sprocket to reach max speed in the cut. The rounder the belly the taller the rakers when comparing to a straight belly bar using the same chain.
On a straight bar that same chain ends up with rakers too low for the larger sprockets to keep their speed up so the smaller sprockets end up cutting faster.

 

[Redfin]

10 pin is faster on the belly bar since it's not rising up out of the groove as much like it does on the other bars.

So the chain slapping back down on a regular bar causes friction slowing it?

 

[Nitroman]

IMHO - the larger the gear/sprocket/wheel the less the torque. So the cannon SBP has a larger "gear"/tip, so it reduces the torque on the cutters coming back towards the saw. Relative, to a smaller "gear"/tip which is on the tsumura.

The other "gear" in the equation ie. the rim sprocket. Which again can also reduce torque by going bigger.

So big gear(10pin) + big gear (wide tip - cannon) = less torque than big gear (10pin) + smaller gear (narrow tip -tsumura).

smaller gear (9pin) + big gear (wide tip -cannon) = basically same torque as big gear (10pin) + smaller gear (narrow tip - tsumura)

that is the way I am seeing it...so far anyway. lol

What!? The only forces your are dealing with are torque and friction (drag). The engine makes the torque and everything else wants to reduce that.

This is EXACTLY why a test fixture is necessary when making these entirely subjective tests. And as long as a human being is touching that saw, it IS subjective. You spent a great deal of time learning essentially, nothing.

 

[Definitive Dave]

I submit that while a test fixture can tell you which mods to the saw produce the most HP and torque.
Without the other elements in place including wood, you wont know what combo is fastest in the cut.
I want a good accurate dyno like the roses want the rain but it wont eliminate all the testing that goes into finding the fastest setup for a saw.

 

[thomas1]

I submit that while a test fixture can tell you which mods to the saw produce the most HP and torque.
Without the other elements in place including wood, you wont know what combo is fastest in the cut.
I want a good accurate dyno like the roses want the rain but it wont eliminate all the testing that goes into finding the fastest setup for a saw.

I'm thinking he means a test fixture that will hold and apply a constant load to the saw during the cut, removing the human variable from the equation.

Humans have lots of things that influence the way they perceive information and those perceptions aren't always reality.

 

[Chainsaw Jim]

Learned nothing my big brown arse!

Thank you redbull661 for taking the time to share this very interesting and time consuming test with us.

 

[redoakneck]

Many factors involved here

Need human element as robotic as possible


Need 100's of cookies to be statistically accurate

Wood needs to be really, really uniform, like a cant??

Thanks redbull, your tests are very interesting, send me that belly when yer done, needs an inspection

 

[Philbert]

Correct me if I am wrong but a saw has torque and the combination of saw, sprocket, bar and chain have cutting speed.
I see people say that such and saw combo doesnt have as much torque as another, but isnt that an inaccurate way of at least phrasing it.

Nothing is free Dave. Torque and speed are a trade off. Think about the gears on a bicycle (at the pedal / crank, since we are talking about drive sprockets), or the transmission in your car or truck.

While the motor (or cyclist) may produce different torque at different speeds, the final torque and speed are a result of gearing.

If speed were 'free' we would all run big sprockets.

On a straight bar that same chain ends up with rakers too low for the larger sprockets to keep their speed up so the smaller sprockets end up cutting faster.

Were'nt 2 of the bars 'straight' bars? Did they behave different?

Philbert

 

[Adirondackstihl]

 

[Mastermind]

Good stuff Julian.

You are a testing machine in your own right. Carry on.