Alaskan Mill: 066: Saw not cutting straight?

[bandyfro]

Hi

I have an Alaskan Chainsaw mill with a Stihl 066. I am milling a Eucalyptus spp. with it, it is my first attempt with this mill. It is bloody hard work. I bought a ripping chain for the job and cut a dozen boards before I sharpened the chain with my brand new little electric grinder (I think its called a super cut) I sharpened the chisels first and then went to lower the guides but found that because it is a ripping chain and the chisels are further apart than a standard chain the flat guide on the grinder couldn't lie across 2 chisels in order to lower the guides correctly... bugger! So I done my best and lowered the guides as good as I could. I went back to my logs and cut a few boards off the narrow logs at the top of the tree without much bother apart from a little chain chatter. Then I tried to slab the bigger logs at the bottom of the tree which was about 350-400mm in width. I didnt get more than a few feet into my cut when the front of the saw started to rise up. It eventually wouldn't cut anymore because of this 'twisting/rising' action of the bar in the cut. I was able to finish the slab by using a second saw to clean/ flatten the twisted cut before continuing with the mill saw. This happened 3 times on this slab and was very frustrating.

My question is, what is happening in this scenario? Is it because some chisels were sharpened more than others, maybe more meat was removed on the left cutters than the right? Is it all because the guides are a bit off? Maybe it is unrelated to the sharpening and is the width of the slabs? Maybe I'm such an amateur that I am just missing a bit of vital 'chainsaw use' knowledge. Any help will be appreciated. Thanks

[teakwood]

never ever lower the rakers when sharpening a chain, especially when you using a mill and in hard wood. I bet you lowered the rakers too much.

you sharpen the chain 4-5times before lowering the rakers and then you have to be very gentle, just one or two strokes.
are you using a 10 degrees chain? they are special designed for chainsawmills and are a must for hard wide cuts

[EarlyAchres]

never ever lower the rakers when sharpening a chain, especially when you using a mill and in hard wood. I bet you lowered the rakers too much.

you sharpen the chain 4-5times before lowering the rakers and then you have to be very gentle, just one or two strokes.
are you using a 10 degrees chain? they are special designed for chainsawmills and are a must for hard wide cuts

Sub'd on this one as I am about to slab a few logs with a CSM I welded up a week ago. I also bought a ripping chain for my MS660. I am confused about the above statement because it says to "never ever" lower the rakers but then says to lower them after 4-5 times. It seems to me that to measure the raker height you could use a straight edge laid across the chisel teeth and then use a feeler gauge to determine where you are at for raker height. I have read that this is how it is done when you don't have the pre-made gauge. Also I think it would be a good idea to check your raker height as I have checked new chains and found they are not always accurate or consistent on raker height. You would have to know what height is correct as you could get them too low. To get back to the original poster, I think it is possible that the chisel sharpening was done on one side more than the other. This is common on crosscut chain and causes a cut to curve (I have done this myself on non ripping chain). I don't know how to correct this but maybe someone else will chime in with a good answer (then I can correct my 16" cross cut chain!). Oh, Happy 4th!

[bandyfro]

Teakwood, Yes I have a 10 degree chain. Are you saying that the lowered rakers are the cause of the wandering cut or just giving me some additional advice?

The logs I am cutting are definitely in very hard wood.

[teakwood]

never ever lower the rakers when sharpening a chain, especially when you using a mill and in hard wood. I bet you lowered the rakers too much.

you sharpen the chain 4-5times before lowering the rakers and then you have to be very gentle, just one or two strokes.
are you using a 10 degrees chain? they are special designed for chainsawmills and are a must for hard wide cuts

Sub'd on this one as I am about to slab a few logs with a CSM I welded up a week ago. I also bought a ripping chain for my MS660. I am confused about the above statement because it says to "never ever" lower the rakers but then says to lower them after 4-5 times. It seems to me that to measure the raker height you could use a straight edge laid across the chisel teeth and then use a feeler gauge to determine where you are at for raker height. I have read that this is how it is done when you don't have the pre-made gauge. Also I think it would be a good idea to check your raker height as I have checked new chains and found they are not always accurate or consistent on raker height. You would have to know what height is correct as you could get them too low. To get back to the original poster, I think it is possible that the chisel sharpening was done on one side more than the other. This is common on crosscut chain and causes a cut to curve (I have done this myself on non ripping chain). I don't know how to correct this but maybe someone else will chime in with a good answer (then I can correct my 16" cross cut chain!). Oh, Happy 4th!

Sorry for the confusion. "Never ever" was definitively the wrong word! in CSMilling the rakers can not be low, that will kill you cut and the chainsaw also. if you in hard wood they should be half deep of whats normal, although i have never used skip or semi skip chain as they are not available in Costa Rica.

[teakwood]

Teakwood, Yes I have a 10 degree chain. Are you saying that the lowered rakers are the cause of the wandering cut or just giving me some additional advice?

The logs I am cutting are definitely in very hard wood.

Measure the rakers dept. if they are deeper than 0.5mm file back you tooth until they are less than that. 0.3-0.5mm is good. and then go make a cut to see if that works. Lots of things in life are trial and error

[mike_belben]

look your bar over to be sure its flat, doesnt have saddles worn into the rails and is the correct guage to match the chain.  

I suggest putting on a new standard chain to verify the mill cuts flat before fooling any more with the other chain.  You could waste a lot of slabs over it.  

To check raker height get yourself a guage.  a 4 inch or so chunk of steel thats been surfaced will do fine.  Clamp a bar in your vice, lay the chain in it and at the flattest point use your gauge over the top of any two cutters on the same side.  Offset to the left or the right.  Now use a feeler gauge to check and adjust your rakers.  

Before this, rig up a simple little clamp on height checker to the bar, to even up cutter height.  Think of a truck going under a bridge.  The cutter thats too tall catches on your little clamped on doodad.   File until they all just pass.  Then dress rakers.

[JohnW]

bandyfro, how much spare bar length do you have.  Is it possible that the clamp nearest the saw is getting caught on some part of the log?

[mad murdock]

As Johnw said. Check the mill over removed from the saw, to make sure nothing is bent or tensioned wrong, putting stress into the bar. Also as started your parallel on the bar rails is a key item. If your rails aren't parallel you need to straighten them by drawfiling them or grinding them straight. Then evennes on the sharpening. Making sure the cutters are all near the same length and follow teakwood's guidance on Esler height. You should get back to good cutting order after looking over all the little details. Cutting consistent straight cuts with a CSM is all about the little details. 

[bandyfro]

Hi again folks

I bought a new ripping chain and the CSM cuts straight again. The problem was obviously the rakers. I will follow your directions and will continue on with more care when sharpening the chain and leave the rakers alone until I absolutly have to lower them.

Thanks very much for the advice.

Cheers

[Greyman]

In my experience, this is often caused by a difference in filing angle from the two sides.  It happens a lot when people file all cutting teeth from the same side of the bar when using a guide.  It just takes one bad sharpening then you blow out the bar groove and it's never the same.  Not sure how your electric grinder works but the first thing I would do is go back and check the angles.

[HolmenTree]

Take a 2 ft carpenter square and put it on the bar rails with the verticle side of the square butted up the side of the bar. 
Move the  square down the length of the bar while looking at the horizontal straight edge riding on top of the rails.
Do you see one rail lower then the other?

[Gary Davis]

sounds like one side is sharper then the other 

[maple flats]

The issue was likely twofold. First, cheap electric sharpeners are too poorly made to do a proper sharpening. Two, don't touch the rakers for at least 5 to maybe as many as 7 or 8 sharpenings. For that, wait until after sharpening the cutters and trying to saw, you don't get enough bight.
As to electric sharpeners, they take practice even on the good ones and I doubt any amount of practice will result in a properly sharpened chain on a cheap sharpener. They are just not rigid enough to hold true.
On the bad chain, I suggest you have it professionally sharpened, and be sure to mention you may have lowered the rakers prematurely. He may need to remove extra from the cutters to get it back to what it should be. That being said, it is likely not ruined, but it's useful life has been shortened, just think of it as a good lesson.