Chainsaw inertia brake

[Rich2484]

OK tomorrow I will take my 390 and swing it as fast as I can under full revs and you can put your arm in its path.

 

The inertia brake operates when the saw impacts, that’s why the manufacturers test is an impact test

 

The inertia test alone is not sufficient because the connection between the chain brake band and the operation handle can be broken, that’s why both tests are needed and described in the manufacturer’s instructions, or do you think they are wrong as well???

 

You have put the bit I need to point out in bold anyway so I don't have to.

 

A kick back occurs when the saw is suddenly impacted on the kickback zone on the bar. I.e when the saw is dropped....

 

Ah sod it its too late I'm out with Steve. Thanks for the link morten I will be saving that one.

[morten]

OK tomorrow I will take my 390 and swing it as fast as I can under full revs and you can put your arm in its path.

 

The inertia brake operates when the saw impacts, that’s why the manufacturers test is an impact test

 

The inertia test alone is not sufficient because the connection between the chain brake band and the operation handle can be broken, that’s why both tests are needed and described in the manufacturer’s instructions, or do you think they are wrong as well???

 

You are simply not making any sense. Sleep on it, or find ANY CREDIBLE SOURCE that supports your claims.

 

The inertia test IS NOT to test what happens when the saw impacts. It is a way of simulating the sudden acceleration that happens when the saw kicks back (as the Stihl article clearly states).

 

And: What are you on about "swing it as fast as I can under full revs" Who said anything about full revs? Why would ANYONE "put your arm in its path".

[Steve Bullman]

And: What are you on about "swing it as fast as I can under full revs" Who said anything about full revs? Why would ANYONE "put your arm in its path".

 

Again, he is misunderstanding the concept of inertia Morten, and believes he could swing the saw fast enough to enable the inertia break.....I guess??

[treequip]

The drop test is performed because its the only way to test the inertia....unless you think that you are quick enough to snap the saw upwards to mimic the amount of inertia a kick back would produce???

 

You need to read up about inertia so you understand it better. Then you won't need to resort to the little quips(scuse the pun) below when you are losing the argument

 

Steve,

 

Inertia is the tendency of a body to resist acceleration or the tendency of a body at rest to remain at rest

 

morten called it accelertion, who dosent understand?

[Mark_Skyland]

 

The inertia brake operates when the saw impacts, that’s why the manufacturers test is an impact test

 

The reason they do an impact test is because there is no way they will want you to test it in the way its designed to work. Ie full revs, nose of bar in contact with timber to cause a kick back. The saw will kick up but the inertia will trigger the brake even if your hand doesn't contact the handle.

 

It's probably a more important test than the well known test we generally do.

[Steve Bullman]

Inertia is the resistance of any physical object to a change in its state of motion or rest

 

ie a sudden upwards movement

 

Anyway, i'm now out of this. If you can prove me wrong i'll keep an eye out and gladly hold my hand up and apologise and send you a free t-shirt.

 

Will you do the same?

[Stubby]

The inertia bit applies to the mechanism not some one swinging the saw about . Some time ( when I'm tired ) I just drop my saw on the ground when its turned off and the inertia mech will activate the brake .

[treequip]

Inertia is the resistance of any physical object to a change in its state of motion or rest

 

ie a sudden upwards movement

 

Anyway, i'm now out of this. If you can prove me wrong i'll keep an eye out and gladly hold my hand up and apologise and send you a free t-shirt.

 

Will you do the same?

 

You want one of my shirts:laugh1:

[santacruz]

I had a gnarly kick back a couple of weeks ago first time in ten years. Nearly pooed my pants, but the chain brake worked (on intertia alone as it happens) and the chain stopped befor it hit my shoulder. There was so much force both hands came off the saw.

[scotspine1]

Watch this vid 1.08 to about 1.12

 

Look at his left hand position and listen to the brake being activated at the moment of kickback. I've used this test (dont try this at home kids) 100s of times with a 70cc saw to demonstrate the inertia brake being activated during kickback.

 

Forget the red cross animation thing and the video narration - inertia brake is activated by kickback, listen to the operator revving the locked up saw immediately after the kickback-

 

1.08 to 1.11 -

 

[ame=http://www.youtube.com/watch?v=M1urRc0y64I]How to Work with Chainsaws - Getting Started - YouTube[/ame]