A different way to sharpen a chain.

[N9WOS]

The OP is smart, but making guesses.

Yes I am making guesses. (but not that smart) When you work with incomplete information, a guess is all you can make.

I keep guessing till I get a system that works for me.

I was just posting it here to see if anyone else would think it was useful.


People can take it or leave it. Don’t bother me either way.

I also appreciate the other information that other people are posting. As they say, you learn something every day. As they say, if your not learning, your probably dead.

 

[Slamm]

As they say, if your not learning, your probably dead.

Or you voted for Obama ...... Sorry, sorry it just slipped, LOL.

Sam

 

[ray benson]

Hopefully one day that slow-motion video of the chainsaw chain will make it to You Tube.

 

[BobL]

Let's not forget that the real work done by the cutter is done with the side plate, not the top plate.

That depends if you are cross cutting or down long milling.

When cross cutting the side plate does indeed cut more fibres than the top plate but whether cutting fibres is more work than punching in between fibres depends on the timber. Interlocking fibre hardwoods are sometimes as hard to cut in either direction.

 

[N9WOS]

Took this off the Carlton site.

Well… If it sets up a feedback loop which keeps the chain in oscillation. Bouncing back between the rail and the wood. Then it should be easy to tape. Just put the chainsaw onto a piece of wood with the power head four or five inches from the piece being cut. With the returning teeth in view. You should be able to see the chain waves being carried out of the cut channel.


The other question with mechanical oscillations is….. What is the parameters needed to maintain it. Will the chain only oscillate like that in long cut channels. Or will it also do that in short ones. Will compression force (downward force) dampen the oscillation.

How that method would remove wood is a depression would move along the cut channel along with the chain oscillation. It wouldn’t be cutting at the entire channel at any one time. It would be chipping away at it in waves.

One obvious place it doesn’t do it is when someone is noodling.

And just because the wood comes out in chips does not mean that it isn’t being removed in a continuous strip from the cut channel. Wood doesn’t bend very well, so it naturally breaks into chunks when it is being cut.

Like a sawmill close to here. When the owner is pushing the logs through at full speed each tooth is removing a good 1/16 to 1/8 layer. The stuff that comes out is in little chunks. I know the teeth isn’t oscillating because the cut marks on the pieces coming out go from top to bottom of the piece. It comes out in chunks because the wood just breaks that way.

I will have to look at the witness marks on some of the wood I have cut to see if, and where there is any indication of tooth oscillation.

Another way a person could find out is start cutting a cake off a big piece and just yank the chain up in mid cut. Knock the cake off of the cut channel and look to see if it looks like the last few passes were continuous from front to back, or if it was going in a wave motion down the cut channel.

I will have to look into this more.

 

[chainsawwhisperer]

This is a fantastic thread, one of the more interesting ones in recent memory CSW

 

[Crofter]

Did you not open my attachments? You can clearly see the intermittent action there in the one picture but it is totally absent in the other; no it was not sanded. You can also see the path of lateral deflection into the end grain which really defines the oscillation pattern. I could also post pictures of fairly uniform 1 1/2" long chip sections that seem quite connected to the same length of cutting dips into the wood. Not in all wood do the chip peels hang together for the whole length of the individual dips: In noodling there is likely a different cutting action forced by the full length long grain shavings. No question they hold together that way but noodling is a whole nother way of cutting.

 

[Tzed250]

Well… If it sets up a feedback loop which keeps the chain in oscillation. Bouncing back between the rail and the wood. Then it should be easy to tape. Just put the chainsaw onto a piece of wood with the power head four or five inches from the piece being cut. With the returning teeth in view. You should be able to see the chain waves being carried out of the cut channel.


The other question with mechanical oscillations is….. What is the parameters needed to maintain it. Will the chain only oscillate like that in long cut channels. Or will it also do that in short ones. Will compression force (downward force) dampen the oscillation.

How that method would remove wood is a depression would move along the cut channel along with the chain oscillation. It wouldn’t be cutting at the entire channel at any one time. It would be chipping away at it in waves.

One obvious place it doesn’t do it is when someone is noodling.

And just because the wood comes out in chips does not mean that it isn’t being removed in a continuous strip from the cut channel. Wood doesn’t bend very well, so it naturally breaks into chunks when it is being cut.

Like a sawmill close to here. When the owner is pushing the logs through at full speed each tooth is removing a good 1/16 to 1/8 layer. The stuff that comes out is in little chunks. I know the teeth isn’t oscillating because the cut marks on the pieces coming out go from top to bottom of the piece. It comes out in chunks because the wood just breaks that way.

I will have to look at the witness marks on some of the wood I have cut to see if, and where there is any indication of tooth oscillation.

Another way a person could find out is start cutting a cake off a big piece and just yank the chain up in mid cut. Knock the cake off of the cut channel and look to see if it looks like the last few passes were continuous from front to back, or if it was going in a wave motion down the cut channel.

I will have to look into this more.

Let me make it easy on you...I have seen the oscillation. The video I have is called "Cutting, Kickback, and Combustion". I was produced by Stihl Inc. in the late '80s. The video of the cutting clearly shows the cutters intermittent action. The cutter has to cut in this way. The chips must break so they can fit into the gullet. If they did not break they would pack the gullet, then wedge the cutter away from the wood. The depth guage regulates the depth of cut by controlling the angle of attack as the cutter enters the wood. As soon as the cutter is to full depth on the rock-back, the depth guage helps to steer the cutter back out of the fiber.

It is all in the video. Sorry that I have not had it converted to digital yet. Art Martin asked me to post it years ago. Maybe this winter I can get it done.

 

[N9WOS]

Did you not open my attachments? You can clearly see the intermittent action there in the one picture but it is totally absent in the other; no it was not sanded. You can also see the path of lateral deflection into the end grain which really defines the oscillation pattern. I could also post pictures of fairly uniform 1 1/2" long chip sections that seem quite connected to the same length of cutting dips into the wood. Not in all wood do the chip peels hang together for the whole length of the individual dips: In noodling there is likely a different cutting action forced by the full length long grain shavings. No question they hold together that way but noodling is a whole nother way of cutting.

Yes, I seen your pictures but I thought you were getting at something else.

If the cut on the left hand side of the “detail” picture is what a chain cut is suppose to look like, then I am stumped (no pun intended).

That is what I try to avoid.
I go for the piece in the right hand side of the picture.

The oscillating pattern I was thinking about would be way smaller than what you have on the left of the pic.

I thought that what you were trying to show with those pictures was what abnormal tooth bouncing (sharpened to produce an oscillating pattern) would produce. (the left picture)

The only time my chainsaws produced the left hand cut is when the thing starts vibrating so bad that it starts shaking the chainsaw apart. When ever I have felt the chainsaw go into a vibration, it would leave that pattern. The first thing I would do is pull it out and take it to the truck to find out what is wrong.

I see what you were getting at with your post now.

I guess none of my chains work like they say they should. (I don't think i want them to, if that is what it entails )

Hmm…… more to think about.

....edit.......
When I am using a chainsaw that has no vibration isolation, and it starts making that pattern on the left, then there is a low frequency hummm that I feel through the handles.

 

[StihltheOne]

Guys.. I gave up on the beer about a dozen posts ago and went to the "crown" method of right brain fluid. I better go to bed and let muy brain grow back after reading this!!!
Very, very good thread.... I think

 

[parrisw]

Didn't know you needed a degree in chain sharpening to get a chain to cut??? WTF Couldn't even get through the first post.

 

[ropensaddle]

I think he's trying to say keep the rakers at the proper hieght. Steve

What rakers I file mine off

 

[cmetalbend]

I will have to look into this more.

Awe chit now you guys did it.

 

[APyontek]

Wow, so i dont know a whole lot about the physics that the chain actually goes through during the cutting process, but i think there was some good information added towards the end. however im still on my journey to figure out the best way to sharpen for crosscutting hardwood quickly when finish doesnt matter.

 

[Crofter]

Square ground / filed chain severs the end grain fiber with a lot less fuzzing it up so you can see the path of the tooth more clearly outlined on the exposed ends. The main light source was low level and to the left to accentuate the surface with shadow. That was not a rough cutting chain. The smoother one was done with much less raker clearance and the sides of the cutter stoned. There I felt that the bobbing of the teeth was non existent and they remained pressed against the bar. It did not load the saw enough to cut fast but would be on a small saw with over sized sprocket. That makes a narrow kerf and removes less wood but would be useless to work with as you need a good margin to keep from pinching the bar or getting bound in big wood.

The picture below would be of a similar tooth. It is cut back to the rear rivet but the raker full height to give a clearance of 15 thou or so. Not enough bite or drag to make the tooth rock back or allow it to bobble as a normal work chain does.
The second picture compares kerf of a standard new 3/8 chain to what it can be reduced to. In this case just a little too much of a good thing as that chain was to easy to bind but it sure would melt wood. That was another experiment.
All things that defeat the normal design of a chains cutting action but can be put to use for special effects like racing. Not unheard of for a good race chain to cut in half the time of a standard chain.

 

[N9WOS]

Usually I go for a tooth that is sharpened with a lot more top plate angle than the Mfr recommendations. Closer to 40 to 45 degrees. And I like hook, I really like the hook. To get the hook, I try to get a good undercut. When I do that, the chain seams to settle down and cut smooth.

They spec 85 degrees for the side plate angle on type 91 chain and 60 degrees on type 72. I probably go for closer to 45. Get a good chisel edge and it rakes the wood out instead of gouging it out.

New chains seem to always vibrate more. After a few sharpenings, it settles down.

When the side plate and top plate angles get to flat to the direction of travel, then the chain starts vibrating and gets jumpy.

 

[GASoline71]

Overengineering at it's finest...

Gary

 

[Crofter]

Usually I go for a tooth that is sharpened with a lot more top plate angle than the Mfr recommendations. Closer to 40 to 45 degrees. And I like hook, I really like the hook. To get the hook, I try to get a good undercut. When I do that, the chain seams to settle down and cut smooth.

.

I imagine when you hit any dirt with a chain like you describe, you get a lot of filing practice in the process of removing the damage it takes to its long thin point.

 

[N9WOS]

Yes, I get a lot of filing practice, and I don’t like the dirt. You got me pegged.
:monkey:
usually it will hold a good top for a day cutting. But I always touch up the chains before a day of cutting.

 

[Husky137]

Overengineering at it's finest...

Gary

Yup. It's a good thing though, because I'm sure that none of the chain manufacturers bothered to do any scintific studies and testing to determine the ideal angles for a properly cutting chain.:hmm3grin2orange: