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  1. #31
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    For the average chain sawer if the correct size file is used, the angle is maintained & the tooth shape looks right ( like the pic) & the height gauge is kept correct to its cutter with the chain snug & square in the bar with little or no sideways movement their on their way to trouble free sawing.
    Cutting angles can & will vary with the type of timber being sawn, ie HWD or SWD
    Same with depth gauge heights, mechanical harvester heads could run with no depth gauge at all because of the power they have to run the chain.
    This is all on the same principal as a simple hand smoothing plane, the more the blade protrudes the more effort it takes to remove the timber, the bottom of the plane being the depth gauges, So as long as the depth gauge is kept at the right height relative to its cutter through out the chain life, it will cut the same thickness of timber with each pass.
    regards inter

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  3. #32
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    Quote Originally Posted by InterTD6 View Post
    So as long as the depth gauge is kept at the right height relative to its cutter through out the chain life, it will cut the same thickness of timber with each pass.
    Chain saw cutters are not like planes because planes with a fixed bevel or bed have a fixed cutting angle for the life of the plane unless those angles are changed. Opening up a plane mouth also does not change the cutting angle but helps the wood clear the blade which can of course just produced tearaout.

    The cutting angle I am referring to is like this.
    Attachment 109107
    In the top image the gullet is narrow so a 0.025" raker will produce a 6º cutting angle in a 3/8.
    In the bottom image the gullet is wider so to maintain the same cutting angle the raker has to be dropped even further than 25"'.
    For a 3/8 chain maintaining a 6º cutting angle means using a Raker height of 1/10th of the gullet width.
    So a 0.5" gullet requires a 0.05" raker height

    Chain saw cutters do not sit flush on the bar and act like a series of little planes. They rock and rise, pulling the chain out of the bar and twisting to establish their own cutting angle based on the raker height, raker profile, gullet width and the hardness of the wood. Not each cutter cuts the same amount during a given pass. On full comp chain only about 1 in 3 cutters reach anywhere near their cutting potential because the chain is porpoising its way along the bar as it cuts. This is not my theory but has been demonstrated with special slow motion cameras under special conditions and also discussed at length on the Arboriste Site and in the Carlton Saw Chain Manual.

    Stihl and Oregon do not mention it probably because they think it is too complicated to bother average joe user with it.

    On a lucas or big saw in small wood it doesn't matter what you really do provided you have some raker set.
    On a chainsaw in big hard wood every little bit helps.

  4. #33
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    Well bob you have confused me with all that, I'm thinking what your descibing is the same as what I am, but mine in a not so complicated way.
    regards inter

  5. #34
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    Quote Originally Posted by InterTD6 View Post
    Well bob you have confused me with all that.
    Yeah I know it's complicated but it does not surprise me that trying to explain it on the web is confusing. When I explained it to people face to face it takes about 15 minutes and a couple of pages of paper covered with diagrams - most of them eventually get it but one or two are still shaking their heads. This is probably why Chain manufacturers like Carlton don't try to explain it to people they just tell people to use their filoplate jig.

  6. #35
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    I know where you are coming from Bob and understand how it works - initially I didn't really get what you where talking about, but having said that, I haven't played with chainsaws much - I wouldn't even own one if I didn't run the mill.

    I feel it is the biggest reason I had trouble with the large bluegum a little while ago - my raker height was a consistent distance below the cutter and as the cutter slowly wore down it effectively reduced my raker height and as such my 'cutting' was ended up being almost ineffectual
    I love my Lucas!! ...just ask me!
    Allan.

  7. #36
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    that sounds to complicated to me. i know the chain comes out of teh bar and tilts each way. that is why a lower angel gives a cleaner cut and a thinner kerf as tehre is not as mutch sideways force.

    as far as im concerned the rakers are there to stop the chain cuttign to deep and boging the saw. thats why on teh lucas i cut the rakers right down i have plenty of power to cut teh extra wood so why shouldnt i use it. it increases the cutting speed a huge amount.

    www.carlweiss.com.au
    Mobile Sawmilling & Logging Service
    8" & 10" Lucas Mills, bobcat, 4wd tractor, 12 ton dozer, stihl saws.

  8. #37
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    My only concern with that Carl is the quality of finish - if it is even and smooth, then that's cool.

    I have to admit I haven't tried ripping the rakers off to see how it goes, but I know the higher the rakers are the finer the cut, but the slower the cut.

    I've got one of those Carlton File-o-plates and have a heap of slabbing to do here at home, one day I should get into a bit of my own 'field trials' to see what I can get....
    I love my Lucas!! ...just ask me!
    Allan.

  9. #38
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    On a Lucas none of this really matters - you can almost remove the rakers altogether because you have so much power.

    The way to calculate these changing raker heights for chain is quite easy.

    Take a brand new chain and measure the gullet width - call that W
    Take note of the raker Height - call that H
    Divide W by H and you have the initial W/H ratio - call that R

    Then at any point during the life of the chain measure the latest gullet and divide that that by R and that tells you what to set the raker depth to.

    Example 1.
    404 cross cutting chain has a gullet of 0.15" and a starting raker depth of 0.025
    W/H ratio is 0.15/0.025 = 6

    When the gullet reaches 0.20" the raker depth below the cutter should be 0.20/6 = 0.033
    When the gullet Reacher 0.40: the raker . . . . . . . . . . . . . . . . . . . . . . . . . . . = 0.066
    I know this sounds like an outrageous amount but it really does work. You might say, "Surely no one uses these raker depths" ask Carl what he uses!

    Example 2.
    My 3/8 10º ripping chain has a starting gullet of 0.25" and a starting raker depth of 0.025
    W/H ratio is 0.25/0.025 = 10

    When the gullet reaches 0.30" the raker depth below the cutter should be 0.30/10 = 0.030"
    When the gullet Reacher 0.40: the raker . . . . . . . . . . . . . . . . . . . . . . . . . . . = 0.040"
    Of course I don't sit there and file them exactly to the last 0.001" if they are within 0.005" Im happy.

  10. #39
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    it dosent affect the finish that is down to the top plate angle.

    you are right about the power of the lucas.

    mine has a 27hp motor and with the rakers cut down to half way on a new chain with 2 blokes pushing we have never been able to bog the saw down. and the chain done like this pils out little lumps of wood not chips. and boy is it fast.

    www.carlweiss.com.au
    Mobile Sawmilling & Logging Service
    8" & 10" Lucas Mills, bobcat, 4wd tractor, 12 ton dozer, stihl saws.

  11. #40
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    What BobL is saying is that when the cutting edge of the tooth bites in to the wood the top of the raker kicks up and touchs the wood and the angel of the cutting tooth is important to get the best cut.

    So this diagram shows that as the tooth is filed back to keep the same angle you need to file the top of the raker down further. To maintain the same angle the gap gets bigger so the top of the raker needs to be filed down further.

    Hope that helps

    Cheers
    regards

    David


    "Tell him he's dreamin."
    "How's the serenity" (from "The Castle")

  12. #41
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    mine has a 27hp motor and with the rakers cut down to half way on a new chain with 2 blokes pushing we have never been able to bog the saw down. and the chain done like this pils out little lumps of wood not chips. and boy is it fast.
    Yeah I'm with you on that Carl, but hows the finish? I don't really want to go to a slabbing job, be over and done with in 15 mins but leave the customer a bunch of washboards...?
    I love my Lucas!! ...just ask me!
    Allan.

  13. #42
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    the finish is about as good as with the rakers at what they are ment to be maby slightly rougher but only becuase the marks are a bit further part but not mutch.

    the roughness is al dependant on the cutter angle.

    www.carlweiss.com.au
    Mobile Sawmilling & Logging Service
    8" & 10" Lucas Mills, bobcat, 4wd tractor, 12 ton dozer, stihl saws.

  14. #43
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    Quote Originally Posted by Calm View Post
    What BobL is saying is that when the cutting edge of the tooth bites in to the wood the top of the raker kicks up and touchs the wood and the angel of the cutting tooth is important to get the best cut.

    So this diagram shows that as the tooth is filed back to keep the same angle you need to file the top of the raker down further. To maintain the same angle the gap gets bigger so the top of the raker needs to be filed down further.

    Hope that helps

    Cheers
    That doesnt compute, if the tooth kicks back to the depth gauge & that is filed more then the cutter angle will be steeper & be more of a scraping cut rather than a shallower cutting angle. Besides who has the time to measure each gullet width & do calculations which may add a poofteenth of a saving when a carlton file plate will give you a choice of 2 accurate depth gauge heights relative to the cutter.
    I always just take a little off my depth gauges by eye every couple of sharpens & if my saw bogs down a bit I just dont put as much pressure on the cut, with the lucas slabber I will just take a little off by eye & test cut, then settle for a smooth cut which is taking out good sawdust, too much & the mill will be trying to push sideways too much & put a lot of extra sideways forces on the frames.
    regards inter

  15. #44
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    Quote Originally Posted by InterTD6 View Post
    That doesnt compute, if the tooth kicks back to the depth gauge & that is filed more then the cutter angle will be steeper & be more of a scraping cut rather than a shallower cutting angle. Besides who has the time to measure each gullet width & do calculations which may add a poofteenth of a saving when a carlton file plate will give you a choice of 2 accurate depth gauge heights relative to the cutter.
    I always just take a little off my depth gauges by eye every couple of sharpens & if my saw bogs down a bit I just dont put as much pressure on the cut, with the lucas slabber I will just take a little off by eye & test cut, then settle for a smooth cut which is taking out good sawdust, too much & the mill will be trying to push sideways too much & put a lot of extra sideways forces on the frames.
    regards inter
    Inter i do the same - when it doesnt cut without a lot of pressure i hit the rakers on the bench grinder - just a hit on each - if it bites too much or "jumps" when you use it "bugger took too much off" and dont lean on it for a few sharpens until it gets better.

    But i was trying to clear up what Bobl was saying. In theory he is correct but in practice how many of us measure the rakers and how many just take a bit off.

    Cheers
    regards

    David


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  16. #45
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    David, that's why I reckon the File-o-plate is such a good little gizmo - no measuring and fiddling around, just stick it on the cutters and over the rakers and it automatically takes care of it for ya
    I love my Lucas!! ...just ask me!
    Allan.

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