Thread: Saw chain advise

more detail needed e.g. Saw make/model, Make and Type of chain, length of bar.

As Bob says, need more details. But you can remove a link and keep using the chains you have.

My main working saws are a stihl farm boss mod 391 with a 20" bar and a stihl magnum with a 25" bar. I started using stihl chain and recently carlton chains (semi chisel) they hold their edge ok but stretch very fast. I've been taking a link out to get a bit more use and have put the stretching down to the fact the timber is so hard.
I try not to put to much load on the saws because it's pretty warm up hear and don't want to over heat the machines as well as letting them idle down for a while before shutting them down as well.
I was talking to a logger a few days ago and he said he uses tungsten chain in local hard wood but they keep throwing teeth and I don't know whether tungsten will resist stretching?

Olmate,

I recent had the same problem with my 066 cutting grey box and redgum. I replaced the oil pump and problem solved.


Pappy

Post a close up side on picture of a couple of your chain cutters and I will give you a chain diagnosis.

Like this if you can - don't worry about the ruler.

Nicecutter.jpg

Originally Posted by Olmate

My main working saws are a stihl farm boss mod 391 with a 20" bar and a stihl magnum with a 25" bar.

What's the pitch and gauge of the chain? Also what cc is the magnum?

I started using stihl chain and recently carlton chains (semi chisel) they hold their edge ok but stretch very fast. I've been taking a link out to get a bit more use and have put the stretching down to the fact the timber is so hard.

Stihl chain is prestretched but Carlton is not. I use mainly Carlton chain and always make them so that the tensioner is at its shortest position to start with (sometimes they are even quite hard to put on the bar even with the chain adjustments at its shortest position) so there is plenty of adjustment after that. They stretch quite a bit in the the first dozen or so cuts but after that they settle down. Even on 60" bar chains I have never had to remove a link and some of the wood I have cut has been quite hard, Tuart, dry Spotted gum and some Iron bark. It sounds like you have other chain issues - post a picture of the cutters and we can take it from there.

I try not to put to much load on the saws because it's pretty warm up hear and don't want to over heat the machines as well as letting them idle down for a while before shutting them down as well

Provided the chain is sharp and you know how to set the rakers correctly you should be able to work those saws hard without overheating. I have temp gauge on one of my saws and don't see much of difference in the running temps of a 20º C day or a 40ºC Day. What makes the biggest difference by far is proving enough oil, and how well sharpened the chain is and how well set the rakers are.

I was talking to a logger a few days ago and he said he uses tungsten chain in local hard wood but they keep throwing teeth and I don't know whether tungsten will resist stretching?

An all tungsten rescue chain will resist stretching better than regular but tungsten tipped chains use the regular steel in the steps and cutter bodies so they will stretch kist a much.

P1040666.JPG
The chain is 3/8 pitch - 25 deg and .063 gauge

Thanks for posting the pics.

This looks like a fairly new chain and cutters don't look too bad to me but have you actually dropped the rakers at all?

More questions

1) How well is the saw self feeding into the wood or do you have to level a bit more than usual as the chain gets older?
If you have to hoike on the saw a bit more as the chain gets older this also suggests you need to drop the rakers more than the standard 25"' and you could try adding a bit more hook to the top plate cutting angle

2) Is the chain making lots of nice fat chips or mainly dust?
If the saw making mainly dust this also suggests the rakers by a couple of swipes and try it out and keep dropping the rakers until it makes more chips than dust.

Although its a newish chain the undersides of the tie straps don't look too worn/flattened so that suggests it is getting enough oil. Does the underside of the bar near the saw get bluish?

3) After how many fuel tank refills do you touch up the cutters and and how often do you drop the rakers?

Thanks BobL
I haven't touched the rakers as I thought I would be exposing more of the front of the tooth and increasing the load on the chain, mabey I've got it wrong.
I sharpen the chain probably two to three times per tank, basically I don't allow it to dull at all otherwise ironwood is too hard to cut.
I'm going to take your advise and take a bit off the rakers and see if that helps.

Originally Posted by Olmate

Thanks BobL
I haven't touched the rakers as I thought I would be exposing more of the front of the tooth and increasing the load on the chain, mabey I've got it wrong.
I sharpen the chain probably two to three times per tank, basically I don't allow it to dull at all otherwise ironwood is too hard to cut.
I'm going to take your advise and take a bit off the rakers and see if that helps.

Wow - even in the hardest wood that seems excessive. For harder woods I would touch up (3 swipes) the cutters after every tankful and give the rakers get 2/3 swipes after every 3 tankfuls of fuel. In soft woods I touch up every 2 tankfuls and raker touch every 6/8 tankfuls.

You absolutely must expose the cutter to more wood as the cutter gets shorter
The raker gauges sold by chainsaw stores work for the first 2/3 uses but after that they just don't take enough off AND as the gullet gets wider even less cutter tip is exposed - this ends up making more and more dust and fewer chips until eventually chainsaw operators throw there chains away as no longer fit for service

After a lot of testing I found the raker depth should be at least 1/10 of the gullet width.
Technically its better to talk about the angle between the "wood, top of the cutter, and the top of the raker" see red line on diagram- I call this the raker angle.
Stock 3/8 chain has a 0.25" gullet and a raker depth of 0.025" or 25"' (25 thou) - this creates a raker angle of 5.7º
I don't reckon this is enough so I file stock rakers to make that angle at least 6.5º - this is for an 880 and 60" bar

RakerProfile.jpg

On my 441 with Lopro 3/8 chain I use raker angles of 7.5º and it fair flies through wood.
On a 391 I would start with 6.5º.

There are quite a few ways to do this.
In this video you can see how I set my rakers using a digital angle finder https://youtu.be/FSr9j2EDoqk
Of course I don't do this every time I touch up the rakers - once the rakers are set with the above method, in the field I just swipe the rakers 2-3 times every 3/4 tankfuls.

You will need to find out what raker angle suits your saw and wood. The easiest way to do this is to just swipe them 2/3 times (this will make the angle higher) and try the chain out, keep doing that (expect more vibe) until the cutters start to grab. Then swipe the cutters a few times - this will shorten the cutters and drop the raker angle back, if it still grabs file the cutters some more.

You won't see this in any chainsaw manuals and very few chainsaw stores or mechnics know about this.
I started a thread on this on the international Arborists website back in 2009 and it has a hundred or so positive comments about how well this system works.

Originally Posted by BobL

Wow - even in the hardest wood that seems excessive. For harder woods I would touch up (3 swipes) the cutters after every tankful and give the rakers get 2/3 swipes after every 3 tankfuls of fuel. In soft woods I touch up every 2 tankfuls and raker touch every 6/8 tankfuls.

You absolutely must expose the cutter to more wood as the cutter gets shorter
The raker gauges sold by chainsaw stores work for the first 2/3 uses but after that they just don't take enough off AND as the gullet gets wider even less cutter tip is exposed - this ends up making more and more dust and fewer chips until eventually chainsaw operators throw there chains away as no longer fit for service

After a lot of testing I found the raker depth should be at least 1/10 of the gullet width.
Technically its better to talk about the angle between the "wood, top of the cutter, and the top of the raker" see red line on diagram- I call this the raker angle.
Stock 3/8 chain has a 0.25" gullet and a raker depth of 0.025" or 25"' (25 thou) - this creates a raker angle of 5.7º
I don't reckon this is enough so I file stock rakers to make that angle at least 6.5º - this is for an 880 and 60" bar

RakerProfile.jpg

On my 441 with Lopro 3/8 chain I use raker angles of 7.5º and it fair flies through wood.
On a 391 I would start with 6.5º.

There are quite a few ways to do this.
In this video you can see how I set my rakers using a digital angle finder https://youtu.be/FSr9j2EDoqk
Of course I don't do this every time I touch up the rakers - once the rakers are set with the above method, in the field I just swipe the rakers 2-3 times every 3/4 tankfuls.

You will need to find out what raker angle suits your saw and wood. The easiest way to do this is to just swipe them 2/3 times (this will make the angle higher) and try the chain out, keep doing that (expect more vibe) until the cutters start to grab. Then swipe the cutters a few times - this will shorten the cutters and drop the raker angle back, if it still grabs file the cutters some more.

You won't see this in any chainsaw manuals and very few chainsaw stores or mechnics know about this.
I started a thread on this on the international Arborists website back in 2009 and it has a hundred or so positive comments about how well this system works.

It looks like I've just scored some valuable advise, I wont be cutting any timber for a week or two but I'll pay more attention to that aspect of the chain and do as you've suggested when I get back up into the bush.
I had a feeling this forum was going to be a gold mine of information, many thanks.

Originally Posted by Olmate

It looks like I've just scored some valuable advise, I wont be cutting any timber for a week or two but I'll pay more attention to that aspect of the chain and do as you've suggested when I get back up into the bush.
I had a feeling this forum was going to be a gold mine of information, many thanks.

No worries.
Just go gently with the rakers, the 390 is not a big saw but it should be able to pull a 3/8 full comp semichisel chains at better than stock raker depth setting. I understand why chainsaw companies are reluctant to not promote this i.e. more wear and tear, vibe and slight increase in kick back potential, but if you don't go over board you will be OK. One bloke in the US uses 9.5º to mill conifers and his saw fair flies through the wood. He used his 660 to mill a heap of boards, enough to build a steep roofed, lofted barn at a remote 5000ft elevation location .

I'm fairly new to chainsaw slabbing. I've got a Turbo Saw this earlier this year and still learning about sharpening my 27rx404 skip chains. I have a bench grinder and sharpen at a 10 degree angle. I also use the FOP on the rackers that I set with a flat wheel at a 10 degree angle. I watch your video using the Wixey gauge and was wondering what angle might you suggest on this chain. If this would help me improve my chains I'm all for it. Thanks for any help.

Originally Posted by xlogger

I'm fairly new to chainsaw slabbing. I've got a Turbo Saw this earlier this year and still learning about sharpening my 27rx404 skip chains. I have a bench grinder and sharpen at a 10 degree angle.

I'm guessing that 10º angle is the "Top plate filing angle" which is what most CS millers use. It doesn't matter what this angle is provided its not less than zero as this will cause the chain to cut a kerf that is narrower than the chain and bind in the cut

cutterangles.jpg

I also use the FOP on the rackers that I set with a flat wheel at a 10 degree angle. I watch your video using the Wixey gauge and was wondering what angle might you suggest on this chain. If this would help me improve my chains I'm all for it. Thanks for any help.

The angle you're generating with a flat wheel is not the angle I refer to when talking about "raker angle" Raker angle is not the angle on the top of the raker but the angle generated by sitting the Digital angle finder on top of the cutter and rocking it over until it touches the top of the raker (zeroing on the bar beforehand).


The angle you are referring to is the "raker angle top", this should always be more than the "raker angle" I refer to above. The worst raker top to use is dead flat - see orange line in diagram below, because it generates a shoulder that generates friction. I don't like using flat tops rakers , even if they are on a slope like the green line as this still leaves a bit of a shoulder. Most CS operators don't realise that raker digs into the wood and having a shoulder on the raker adds more friction. Rounded rakers have less friction and that's why I hand file my rakers. Also I swipe the rakers every 3/4 tanks of fuel with the chain left on the mill so grinders are not able to be used.

My measurements of File-o--plate raker gauges showed that they just don't take enough off the raker and the older and more worn the cutter gets the worse they get. That's why I use the digital angle finder method. The technical name for this is progressive raker depth setting. Oregon do make a series of depth gauges starting and 0.025" and going up to 0.050" in 0,005" increments that can be used but I prefer to be a bit more precise in setting the raker angle.

The shape of the raker is a topic for endless discussion by CS nerds.
If you want to still use a grinder and avoid the shoulder problem you could increase the angle e.g. the brown line, but when using this method, if the raker is being sharpened progressively you will run out of raker well before you run out of cutter. I like using somewhere between he red and blue curve.


raker2009.jpg


The depth you should use for your rakers depends on many things, saw power, bar length/wood width, wood hardness etc. I could waffle on for hours with suggestions but the easiest thing to do is what I wrote above.

The easiest way to do this is to just swipe the rakers 2/3 times (this will make the raker angle higher) and try the chain out, keep doing that (expect more vibe) until the cutters start to grab. Then swipe the cutters a few times - this will shorten the cutters and drop the raker angle back, if it still grabs file the cutters some more.

Of course this is easier to do if you can leave the chain on the mill as swapping chains out is a PITA.

Folks that do this with old chains are amazed that they can get back to cutting as good as new chains and if they are careful about what they do even better than new chains.