I am just now getting decent at sharpening my chains. I always paid someone before last year as I never had time to mess with it. I finally decided last year that I wasn't happy with the way my chains would come back so I started working on it quite a bit more. I haven't tried the progressive raker method yet but am not ever opposed to learning something new especially if it is a better system.
Milling Dead Wood
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Even though your photos are not side on I can tell you don't have enough raker depth. Standard 0.025" depth gauges are extremely conservative in their setting and use a geometry that makes things worse as the cutter wears. For optimum cutting speed the raker depth should not be a fixed distance (eg 0.025") but increase as the cutter wears. By the time my cutters get to what yours look like I'm using around 0.040". A basic guide is to set the raker depth to 1/10th of the gullet width. This is still a moderate setting and for more aggressive cutting try 1/9 or even 1/8. The value used depends on power, width of cut and how hard the wood is. A regular miller that used to frequent this forum (Mtngun) milled the timber for his barn using an 066 from narrow logs and he used 1/6th for his milling. There is a down side to using these settings and that is more vibe, a bit more bar and chain wear, and when out of the mill , a greater chance of kickback.
Everyone I know that has tried this never goes back to gauges.
The other way to find your optimum raker setting for a given situation is to swipe the rakers a few times and try the saw out, repeat this until the saw starts to grab. Measure the raker depth and gullet width.. Of course the actual measurements are not important but the ratio ( raker depth/gullet width) is what matters.
Quietfly
ArboristSite Operative
@BobL do you have a link to a post or a video that shows how to do this?
Im guessing that you mean i should measure the gullet with calipers, and then divide that number by what ever ratio i decide to use ( i was thinking 1/9 or 1/8) and then set the raker to that height. My question is where to measure the raker height from, and which gullet do i measure. Sorry for all the questions, but im still a new born when it comes to this.
Im guessing that you mean i should measure the gullet with calipers, and then divide that number by what ever ratio i decide to use ( i was thinking 1/9 or 1/8) and then set the raker to that height. My question is where to measure the raker height from, and which gullet do i measure. Sorry for all the questions, but im still a new born when it comes to this.
Quietfly
ArboristSite Operative
so i was able to find the answer to most of my questions , Here http://www.hearth.com/talk/threads/chain-sharpening-book.104725/, It discusses everything you talk about , and provides me pictures/ diagrams. I'm going to try to find a FILE O Plate today and try to progressively file my rakers.
Wish me luck.
LOL i haven't even asked about square filing yet.....
Wish me luck.
LOL i haven't even asked about square filing yet.....
FOP's are semi-progressive but ay least they work (sort of) for longer through a chain life than regular gauges do. FOPs are also not very aggressive and they do not allow the operator to optimise their cutting speed. BUT if you can't be bothered with full progressive raker setting then FOPs are a worth getting
Here's a link to a vid showing how I do it.
A couple of explanatory notes about the video.
Instead of measuring gaps and distances I'm using a Digital Angle Finder (DAF).
The DAF is far quicker for raker depth setting and is are also useful for other aspects of milling, like measuring and eliminating twist in log rails
The gullet width to raker depth ratio of 1:10 corresponds to what I call a raker angle of 5.7º (lets call it 6º)
Lower raker angle is equivalent to higher ratios and VV
A ratio of 1:6 = 9.5º (this will rattle your teeth)
Well worn chain set with a standard raker gauge will have a ratio of 1:20 or about 3º
One of my friends once brought me his CS so I could investigate why it was not cutting. The rakers were down to less than 1º - 15 swipes on each raker and he was back in business.
The video shows the initial setting up of a chain that has rakers that are all over the place.
Some of those raker angles were less than 3º (powder makers) and you will see how much filing was involved to get them down to 6ª
It's takes some time to set a chain up but the results are well worth doing.
I don't use the DAF this in the field. I swipe the rakers 2/3 times every 3/4 touch ups and this is usually enough to keep the chain cutting well.
I check the rakers with the DAF back in my shop after every 2/3 days of milling. Usually I am within 1º of the desired angle.
Using this method means it is not necessary to make all the cutters the same length - PROVIDED there is a random scattering of cutter lengths on the chain. Sometimes the cutters on one side (LHS or RHS) do end up differing in length compared to the other side - this is not good and needs to be corrected.
That is one way of doing it and the raker depth can be measure using feeler gauges. I would not suggest starting on 1/9 or 1/8. Start at 1/10 and see how this goes.
Here's a link to a vid showing how I do it.
A couple of explanatory notes about the video.
Instead of measuring gaps and distances I'm using a Digital Angle Finder (DAF).
The DAF is far quicker for raker depth setting and is are also useful for other aspects of milling, like measuring and eliminating twist in log rails
The gullet width to raker depth ratio of 1:10 corresponds to what I call a raker angle of 5.7º (lets call it 6º)
Lower raker angle is equivalent to higher ratios and VV
A ratio of 1:6 = 9.5º (this will rattle your teeth)
Well worn chain set with a standard raker gauge will have a ratio of 1:20 or about 3º
One of my friends once brought me his CS so I could investigate why it was not cutting. The rakers were down to less than 1º - 15 swipes on each raker and he was back in business.
The video shows the initial setting up of a chain that has rakers that are all over the place.
Some of those raker angles were less than 3º (powder makers) and you will see how much filing was involved to get them down to 6ª
It's takes some time to set a chain up but the results are well worth doing.
I don't use the DAF this in the field. I swipe the rakers 2/3 times every 3/4 touch ups and this is usually enough to keep the chain cutting well.
I check the rakers with the DAF back in my shop after every 2/3 days of milling. Usually I am within 1º of the desired angle.
Using this method means it is not necessary to make all the cutters the same length - PROVIDED there is a random scattering of cutter lengths on the chain. Sometimes the cutters on one side (LHS or RHS) do end up differing in length compared to the other side - this is not good and needs to be corrected.
Quietfly
ArboristSite Operative
So i have a daf and saw your description of using a daf to set the raker heights. Ill definitely keep you in the loop.
I'd still like to see a size on picture of a couple of rakers/cutters.
Quietfly
ArboristSite Operative
I'll take a few pictures tonight before i start the "operation".
Quietfly
ArboristSite Operative
Quietfly
ArboristSite Operative
Good to see you have sorted the raker problem and thanks for posting the pics because I can see your chain has other issues
Sorry I can manipulate and label photos at the moment as the graphics card on my laptop but at least I can stop post old photos.
The first things is that it is some sort of safety chain which I don't recommend for milling on a big saw as it reduces the ability of the saw to clear sawdust.
The next thing is your cutters do not have anywhere near as much hook as is necessary.
Some of them like this one even look like they have a negative hook, slope backwards instead of pointing forwards - see below
This will make the chain very slow cutting especially in hard/dry wood. It also adds unnecessary load on the engine and increased B&C wear.
Have a look at these. The top one is Will Malloff cutter and the lower one is mine
Also look at how angled my raker is. This is because it is a wide raker. If the raker is narrow like WMs it does not need to be as sloped as mine.
While cutting the raker actually penetrates slightly into the wood and increases the raker angle and enabling it to grab more wood.
If the raker top is flat you have to file a higher raker angle to grab the same amount of wood as a more pointed or sharp raker.
Raker shape is a second order issue but for those chain ultimate cutter speeds flat tops add more wood/chain friction and so should be avoided.
Sloped or curved have less friction.
I can see a fair bit of tie strap wear on your chain. This is consistent with the cutters having no hook and maybe no getting enough oil.
I'd recommend getting a non-safety chain and setting the rakers to between 6 and 7ª and shape the rakers as discussed - then go and cut some wood and report on what you experience.
Sorry I can manipulate and label photos at the moment as the graphics card on my laptop but at least I can stop post old photos.
The first things is that it is some sort of safety chain which I don't recommend for milling on a big saw as it reduces the ability of the saw to clear sawdust.
The next thing is your cutters do not have anywhere near as much hook as is necessary.
Some of them like this one even look like they have a negative hook, slope backwards instead of pointing forwards - see below
This will make the chain very slow cutting especially in hard/dry wood. It also adds unnecessary load on the engine and increased B&C wear.
Have a look at these. The top one is Will Malloff cutter and the lower one is mine
Also look at how angled my raker is. This is because it is a wide raker. If the raker is narrow like WMs it does not need to be as sloped as mine.
While cutting the raker actually penetrates slightly into the wood and increases the raker angle and enabling it to grab more wood.
If the raker top is flat you have to file a higher raker angle to grab the same amount of wood as a more pointed or sharp raker.
Raker shape is a second order issue but for those chain ultimate cutter speeds flat tops add more wood/chain friction and so should be avoided.
Sloped or curved have less friction.
I can see a fair bit of tie strap wear on your chain. This is consistent with the cutters having no hook and maybe no getting enough oil.
I'd recommend getting a non-safety chain and setting the rakers to between 6 and 7ª and shape the rakers as discussed - then go and cut some wood and report on what you experience.
Pauls_Workshop
ArboristSite Operative
Good to see you have sorted the raker problem and thanks for posting the pics because I can see your chain has other issues
Sorry I can manipulate and label photos at the moment as the graphics card on my laptop but at least I can stop post old photos.
The first things is that it is some sort of safety chain which I don't recommend for milling on a big saw as it reduces the ability of the saw to clear sawdust.
The next thing is your cutters do not have anywhere near as much hook as is necessary.
Some of them like this one even look like they have a negative hook, slope backwards instead of pointing forwards - see below
This will make the chain very slow cutting especially in hard/dry wood. It also adds unnecessary load on the engine and increased B&C wear.
Have a look at these. The top one is Will Malloff cutter and the lower one is mine
View attachment 492807
Also look at how angled my raker is. This is because it is a wide raker. If the raker is narrow like WMs it does not need to be as sloped as mine.
While cutting the raker actually penetrates slightly into the wood and increases the raker angle and enabling it to grab more wood.
If the raker top is flat you have to file a higher raker angle to grab the same amount of wood as a more pointed or sharp raker.
Raker shape is a second order issue but for those chain ultimate cutter speeds flat tops add more wood/chain friction and so should be avoided.
Sloped or curved have less friction.
I can see a fair bit of tie strap wear on your chain. This is consistent with the cutters having no hook and maybe no getting enough oil.
I'd recommend getting a non-safety chain and setting the rakers to between 6 and 7ª and shape the rakers as discussed - then go and cut some wood and report on what you experience.
Bob: Just wanted to say thanks for all your knowledge. I and others are learning alot from most all of your discussions in this one and other threads. I'm *finally* getting it on the progressive raker grinding with your video on it. I'm hobby milling just two years. I'm going to start trying it. I especially like how using this you don't have to have each cutter exact same length as that is tedius to do and somewhat wasteful of cutters and chain life too.
I may have a question for you. I have a couple chains now that want to cut non vertical as they cut. You end up with rounded cuts that are supposed to be straight just trying to cut straight down milling a log. One side of chain/blade is cutting more than the other side. After a bit, the blade won't cut at all and gets stuck in the log. These chains are sharp. The cutter lengths I set to all be the same. The rakers are pretty deep but not progressive, about 0.040 and are all the same. One chain is missing two teeth, but one on each side. The other chain is missing about 3 teeth from hitting some barb wire. I' thinking that is the problem, but the missing teeth make it more like a skip chain there, which doesn't have any problems by nature. Should I cut off some more teeth to make it more of a skip chain? Does it matter if it isn't perfectly symmetric skip, as long as total number of missing teeth is same on left vs. right sides of chain? My one is same number, but still has the problem. I'm using an Echo 60 cc cs-590 for milling at the moment, soon to use a cs-8000 80cc. US hardwoods like Ash, English Walnut, Maple. I want to use these milling chains as long as I can possibly. They are only about 1/3rd life gone on them now. Thx- Paul
Quietfly
ArboristSite Operative
post pictures of your cutters and he'll be able to give you an evaluation.
Paul,
Do you have the oiler on the echo turned all the way up. The smaller saws often won't put out enough oil to keep everything working smoothly and will cause excessive wear on the chain and bar. Is the bar nice and straight. Could have got a small bend or twist in the bar and that is causing the trouble.
Do you have the oiler on the echo turned all the way up. The smaller saws often won't put out enough oil to keep everything working smoothly and will cause excessive wear on the chain and bar. Is the bar nice and straight. Could have got a small bend or twist in the bar and that is causing the trouble.
Pauls_Workshop
ArboristSite Operative
Funny you ask just exactly that. Well, i did. I have a 20" and a 28" bar for my cs-590. I had it set all the way, but messed with it and found I had the direction wrong on it. So I did mill with the 28" bar a bit on "low" setting instead of intended high setting as I had it backwards. And that 28" bar does have a very slight bend to it now that I am fixing after only about 500 sq ft of milling use. But only the very bottom of bar has any wear to speak of, but is just slightly darker color there. I did manually add oil to the bar every foot of milling with it also, so not without any oil. I'm also not sure that bar didn't get the bend from the Alaskan mill clamps on the bar. I kind of think they did it. Talking about maybe 1/8" at end of bar vs. other end so not terrible.
Having said all of that, I also have two other older chains that want to not cut straight down vertically on another saw I have (42 cc Poulan). And those aren't missing any teeth at all. So there is something I'm not doing right and missing. Could be a couple root causes of the problems. I can grind the teeth sharp no problems and cut 1" streams of wood milling, but after 6 or so grindings, I'm messing things up as they don't want to let the saw cut straight anymore, just noodling a log down vertically by hand.
I use a Dremel with some diamond impregnated grinder bits to do all my chain sharpening by hand. I use flat teeth fronts with not more than 10 degrees on them, or less for milling. - Paul
Pauls_Workshop
ArboristSite Operative
Yes, pics maybe later on. I'm not setup at the moment to do photos well at all. By the way Quietfly, I have milled lots of hard white ash about 18" width, 8' long with just my 60 cc CS-590 last year. About 800 board feet of it or so, some dead at least two years. It cut it no problems, just took some time. I could do one pass in about 8 minutes. So I think if you can follow Bob's advice, you should be able to cut all that hard ash with your setup as your saw is much more powerful. A smaller bar also would increase your chain speed which would help due to less friction, as would considering using a full skip chain instead of a normal chain for less force required or torque required per spin around the bar from the saw. That would increase chain speed too. I found using the 28" with full skip, the CS-590 would cut just as fast speed or better milling than using normal non-skip chain with my 20" bar setup. - Paul
That's nowhere near enough oil - oil added to a chain on a one short operation lasts for 2/3 passes of the chain around the bar as it is rapidly flung off the drive and nose sprockets by the severe centrifugal forces. It time that translates to about 0.1 s before it needs more oil so the oil must be added continuously to be effective.
Thos chains have been run on an bar with bar rail tops not square to the side of the bar. This wears the underside of one side of the ties more than the other - after that the chain will never cut straight. Keeping the bar dressed square eliminates this problem
I had a feeling this might be the case. Glad Bob showed up to offer his info. Paul it isn't that hard to build a rudimentary auxiliary oiler that will help out a lot. Just need something to continually drip some oil near the edge of the bar after the chain rounds the tip. The oil will find its way to the edge of the bar and do its job.
No it won't, the chains speed is determined by the RPM of the sprocket and the size of the sprocket.
Shorter bars do have less friction but having fewer cutters means they are used more often so go blunt faster - overall you won't see much difference between say a 25 and a 28" bar but you would of course see a difference if you went to 42"
There is a poor understanding of how useful skip chain is on short bars.
What most folks don't understand is that not every cutter on a full comp chain takes the same size cut or chip. Saw chain does not operate like a wood plan sliding along the bar rails taking nice shavings. Saw chain porpoises up and down on the chain and carves out chips more like a chisel.
The first thing that happens is - [IN SLO MO] the cutter grabs a little wood. This lifts the cutter off the chain slightly and pushes the raker into the wood so digs in a little increasing the raker angle. The cutter then starts to bite more lifting the cutter more, the raker digs in a little more, further increasing the raker angle and this is repeated until the cutter can penetrate no further. By now the cutter is well above the bar rails. Except when noodling the chip is not shaved out, but pulled out by a combination of the engine power and chain tension. This, by the way, is why chainsaw injuries are so traumatic because the meat is literally pulled out !
The cutter behind the cutter that has grabbed wood does not grab as much wood, and the cutter behind that grabs even less wood.
Then the cutting sequence starts all over again. This means in practice that full comp already acts like sort of skip chain.
Only in really long bars will skip make much difference.
Skip chains have fewer cutters so they grab wood more often and so go blunt quicker so the net effect is not as pronounced as people think.
The differences people observe are often due to the use of new chains, or chains with incorrectly set rakers.
Pauls_Workshop
ArboristSite Operative
Hey guys and Bob: Thanks much for your replies. Bob: can you please answer my original question? What to do with my chain with a few teeth out of it: Should I cut off some more teeth to make it more of a skip chain? Does it matter if it isn't perfectly symmetric skip, as long as total number of missing teeth is same on left vs. right sides of chain? What should I do to get these chains usable again with the missing teeth?
I'll comment a bit on some of the other comments:
No it won't, the chains speed is determined by the RPM of the sprocket and the size of the sprocket.
Shorter bars do have less friction but having fewer cutters means they are used more often so go blunt faster - overall you won't see much difference between say a 25 and a 28" bar but you would of course see a difference if you went to 42"
Bob, not questioning "MAX SAW CHAIN SPEED POSSIBLE", which is controlled as you say by the RPM of the sprocket and size of the sprocket. But when buried deep in a log milling, and NOT HAVING A 80cc or huge saw doing it with huge torque, smaller saws WILL bog down in the cut as the friction of milling is high, especially if the streams of cuttings just can't get out and ACTUAL REALIZED chain speed then drops. What I was stating above was NOT OPINION. I am stating FACTS from running my saw this way in the same wood cutting it the same way. The 28" bar with full skip chain on my Echo CS-590 60 cc cut FASTER, more CONSISTENTLY, without BOGGING DOWN deep in the cut as with full normal tooth cutters with the 20" bar on it. This is a fact. Now we can all discuss and debate WHY this is, but it is a fact, and one I think can help this forum to consider. I believe it is mainly due to having the space on the chain to allow the streams of wood to actually get out of the cut much better with the full skip. AND the actual speed of the chain WAS much faster as the wood chips did not bog down the saw due to friction.
I'm sharing this here because not everyone milling has huge saws yet, and this was key for me to be able to cut the ASH well with a smaller saw. Lower the friction in the cut as much as possible to maximize the potential any saw has. I'm now of the opinion myself that FULL SKIP or at least SEMI-SKIP can make a much better ripping/milling chain than normal chains, just to allow the streams of wood an easy path to get out of the cut and not bog it down, more so with the horizontal cutting Alaskan type mills than vertical. It worked for me. I spent my first year milling with a little 42 cc saw. So I'm learning what matters with a little, low torque, lower power saw to mill. May be a different perspective than most people on this forum with only the giant milling saws... The Poulan with a semi-skip did fine with the vertical min mill up to 16" dia or so max.
The explanation on how the cutters work is excellent Bob and thanks for that!
Thos chains have been run on an bar with bar rail tops not square to the side of the bar. This wears the underside of one side of the ties more than the other - after that the chain will never cut straight. Keeping the bar dressed square eliminates this problem
Thanks, I will do some serious bar investigation on those chains/saw next. Could be. The bar isn't that old though or worn. Paint still all on it. I will do some careful inspections.
That's nowhere near enough oil - oil added to a chain on a one short operation lasts for 2/3 passes of the chain around the bar as it is rapidly flung off the drive and nose sprockets by the severe centrifugal forces. It time that translates to about 0.1 s before it needs more oil so the oil must be added continuously to be effective. and ... Paul it isn't that hard to build a rudimentary auxiliary oiler that will help out a lot.
Right, milling on "low" was not intended. Milling on "high" isn't bad though with the echo. It puts out alot of oil. I do need to make an auxilliary oiler for the big bar once I get the bend out of it and use it again. What I did without having that setup yet was to add a bit to the end of the blade every foot or so of cutting which did help a bit when I did it. Also let the saw cool down and idle a minute or so every foot this way. I've only cut about 300 board feet so far with my 24" Alaskan Mk2 Mill using the 28" bar. All my previous milling was just with the top down mini mill that pivots on the bar. I've found with that, it requires less saw size and less oil to mill well than with the horizontal milling with the Alaskan. I think again because the chip streams can easily get out of the cut vertically vs. horizontally, plus the binding on the saw blade isn't there with vertical cuts, as with horizontal the wood slab will press down on the blade while cutting more (even with wedges moved frequently). Low friction is good, high is bad, unless you have a giant saw and it doesn't matter much.
One more quick question: What oil type is best for milling? I've heard car oil like 10W-30 is terrible, bad, don't do it! And I've also heard the lower viscosity is great for milling and getting where it needs to be. What does the forum recommend?
thanks all - Paul
