Optimum Cutter Angles

[Haywire Haywood]

A friend of mine once told me that he changed the angle of the cutter to suit what he was cutting. Is there an ideal angle for hardwoods? I have my grinder set to 30 deg.

thanks,
Ian

Edit: This is in reference to round ground chisel and semi-chisel.

 

[Haywire Haywood]

After reading thru the old threads that Fish dredged up, I guess it depends on the chain in question.

Ian

 

[SawTroll]

After reading thru the old threads that Fish dredged up, I guess it depends on the chain in question.

Ian

Yes, and the saw and wood in question, etc.....

Generally, more angle is for soft wood, less for hard wood - but there are so many variables that you will have to try different options to really know.

At least this is how I see it.

 

[Grande Dog]

The greater the angle, the larger the kerf is, and the more power rquired.

 

[314epw]

angle

And you mean a 25 degree top angle will have a larger kerf than a 30 degree top angle?

 

[Grande Dog]

It's just the other way around.

 

[manual]

The greater the angle, the larger the kerf is, and the more power rquired.

understand the angle changes power. but kerf ? the the tooth is still the same width.

 

[Canyon Angler]

understand the angle changes power. but kerf ? the the tooth is still the same width.

I'm thinking the teeth "grab" and pull out to the left and right, in the same way that they "grab" as they dig in and are limited by the rakers/depth limiters...and the more they grab and pull away from the centerline of the chain left and right, the wider the kerf gets...am I right Grande Dog?

 

[Haywire Haywood]

I was thinking that the more angle there was, the more of a "slicing" action the tooth would have as opposed to a straighter angle gouging the chip out. I suppose I'm just nit picking and there's no real practical difference when cutting firewood.

Ian

 

[Kneejerk Bombas]

I'm thinking the teeth "grab" and pull out to the left and right, in the same way that they "grab" as they dig in and are limited by the rakers/depth limiters...and the more they grab and pull away from the centerline of the chain left and right, the wider the kerf gets...am I right Grande Dog?

The movement, left and right, is limited by the play in the bar grove, against the drive links. Is he then suggesting that a chain with smaller angles would ride in more of a staight line, not moving to the outside limits of chain play?

 

[Lakeside53]

It's just the other way around.

The "kerf" - width of cutter, is the same, no matter the angle. What am I missing here?

 

[Kneejerk Bombas]

Cutters act independently, right and left. The width of a single cutter has nothing to do with kerf width.

 

[Lakeside53]

I mistyped and was going to get back to it, but...

O.k, a pair of cutters sharpened at any (reasonable) angles have the same kerf...

 

[Kneejerk Bombas]

Did you notice this thread: http://www.arboristsite.com/showthread.php?t=37807
The .005 slop could account for quite a bit of kerf width by the time it's said and done.

 

[Lakeside53]

They are both going to pull to the outside no matter what the "reasonable" angle.

Forget the new bar measurements - check out some worn bars. Ha!

 

[Kneejerk Bombas]

The pull to the outside will be compensated by the pull to the inside by the chain tension supplied by the engine and centrifugal force.

 

[Lakeside53]

Good theory. What if if I said the cutter sideways force balance those forces you mention. All theory.... and does anyone really care??

 

[Haywire Haywood]

OT, but ok... weak thread subject anyway. I think what we're missing here is the torsion stresses on the chain. One link is pulling left, and the next pulling right. If there is enough slop in the groove, the rivets are loose enough to allow the chain to twist, and one cutter is pulling more than the other then it will cut crooked.

talk about picking nits... :help:
Ian

 

[B_Turner]

Sam Madsen told me they spent a lot of time looking into the sharper angles and wider kerf thing. Testing and measuring, both with regular saw and race saws and says Madsens doesn't believe it. I have not idea, just reporting what he told me.