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Thread: Jointer Cutter Heads - How many types are there?

  1. #1
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    Jointer Cutter Heads - How many types are there?

    I am trying to sort out the often-discussed cutter head issue as it applies to jointers.

    I am familiar with straight blades. I also understand the advantages of upgrading to something other than straight. I am just trying to distinguish the differences in the alternatives.

    I have seen references to helix, spiral and Byrd. Are helix and sprial synonomous terms? If not, what is the difference? The Byrd is the cutter head with the small four sided cutters, which are rotatable, no?

    Now my last question. What are the advantages of each of these to each other? Is the Byrd the "cadillac" of alternative jointer cutter heads, or is it merely an equal to a spiral or helical head?

    I thank you in advance for educating me.
    Regards,

    Glen

    Woodworking: It's a joinery.

  2. #2
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    These are the ones I have found.

    Resharpenable Straight Blade
    Disposable Straight Blade
    Square-cut carbide insert - these have the insert in a spiral pattern around the head with the cutting edge square to the stock
    Angle-cut carbide insert - these have the inserts in a spiral pattern around the head and contact the stock on an angle, increasing the shear angle of the cutter

    With that said, there are quite a few names that they go by. Helixical, Shelix, Byrd, and spiral to just name a few. With the carbide insert heads, the main difference is the approach angle the cutter contacts the stock. Each head that I have looked at either states which it is or is obvious from the picture. (FWIW, Grizzly sells all four types for many of their jointers)

  3. #3

    Trying to figure out the pro's and con's of knives vs. spiral cutterheads

    I'm getting ready to pull the trigger on an 8" jointer and I'm in the same boat as Glen. I'm trying to evaluate the pros and cons of whether to get a jointer with traditional knives or a carbide spiral cutter head.

    From what I've read here and other places here are the pros & cons:

    - Straight knives:
    -- Pro = Lowest initial cost
    -- Pro = Smooth cuts on normal stock
    -- Con = Will lose sharpness sooner than carbide head
    -- Con = New knives alignment is somewhat time consuming / difficult

    - Spiral carbide cutter heads:
    -- Pro = Better cuts on figured grain stock
    -- Pro = Carbide cutters stay sharp longer
    -- Pro = When edges get dull easy 1/4 turn on cutter to fresh carbide edge
    -- Con = Higher initial cost
    -- Con = Leaves small ridges after jointer pass across spiral cutter head

    For the carbide spiral cutter heads here's what I understand (may or may not be correct ):
    - Byrd head has carbide cutters on an angle to shear cut (most preferable) and Byrd head is considered "tops"
    - Other manufacturers have heads with "shear" angled cutters
    - Straight angle carbide cutters still do the job, but not quite as smoothly as the Byrd or angled carbide cutters
    - All carbide spiral cutter heads leave minor “ridges” after jointing operation

    Those who have more knowledge, please fire away and either confirm or correct my understandings!

    Billbo
    Smyrna, GA

  4. #4
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    Be careful. Spiral does not always mean a Byrd type(indexable carbide head). They do make a head that has flexable straight knives that wrap ariound the head in a spiral pattern. I believe shelix always refers to indexable cutters. You also left out Tersa but I have never figured what they are.

  5. #5
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    Quote Originally Posted by Bill Borchardt View Post
    - All carbide spiral cutter heads leave minor “ridges” after jointing operation
    No more or less than any jointer cutter head style. A cutter that rotates past a flat surface leaves a concave cut; it has to. The speed at which the material passes the cutter will increase or decrease the gaps between these cuts thereby making them more or less obvious. Find the right feed rate for your machine and the marks become essentially invisible.

    Did we mention shear cutting straight knives or HSS spiral heads (I never have figured that one out)? They're out there to. There is plenty to choose from and fans of various camps based on type of use, budget, type of material most used, etc.

    The quality of cut on cooperative woods with HSS knives and carbide spiral cutters seems about the same to me. The degradation of that quality is slower on carbide but we know that from our saw blades, router bits, shaper heads and so forth, eh?

    Tearout prone woods come off the spiral head cleaner and with less waste than even a brand new set of straight knives. Wetting the wood and other techniques can minimize this problem.

    I can only speak from my experience. Based on use and elapsed time; on my knifed jointer I would have been through 4 sharpenings, tossed that set, bought a new set and had it sharpened once. I am still on the first of four carbide edges with no signs yet of fatigue.

    This is just what I observe in my shop and with the materials I use (and the way I use them ). Others will have different results and opinions. Read it all, digest it and make a choice that best meets your requirements. Or get as close as you can; I really miss the mark sometimes on what I thought I needed .
    Last edited by glenn bradley; 12-24-2009 at 2:30 PM.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  6. #6
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    Glen - let me add to your confusion!

    I have an INCA 10" Jointer/Planer, about 15 years old. It has straight knives, BUT the cutter head is angled about 2 degrees off perpendicular giving it the same advantage as a slightly skewed hand plane. I have the knives sharpened periodically and reset them using the "moving wood method," about a ten minute operation.

    It still leaves a finish like glass; no ridges, very little tear-out and no snipe. Would I replace it with a new jointer with a helix, spiral, or whatever cutter? Not on your life!

    Just another alternative to consider. They're occasionally available used.

    Merry Christmas Eve!

    Doug

  7. #7
    Quote Originally Posted by Cary Falk View Post
    You also left out Tersa but I have never figured what they are.
    tersa is a straight knife head that is easy to change the blades in no setting just swap and go

  8. #8
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    Quote Originally Posted by glenn bradley View Post
    No more or less than any jointer cutter head style. A cutter that rotates past a flat surface leaves a concave cut; it has to. The speed at which the material passes the cutter will increase or decrease the gaps between these cuts thereby making them more or less obvious.
    Glenn,

    Do the ridges people have referred to with carbide jointer cutters run the length of the board being jointed (meaning wood missed by the cutters) or across the width, which would be the machining marks you note?

  9. #9
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    Plus if you get into owwm, you get 2, 3 and 4 knife cutter heads...
    Where did I put that tape measure...

  10. #10
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    Quote Originally Posted by Frank Drew View Post
    F

    Glenn,

    Do the ridges people have referred to with carbide jointer cutters run the length of the board being jointed (meaning wood missed by the cutters) or across the width, which would be the machining marks you note?
    Folks are referring to scalloping across the width of the board. On most spiral cutterheads I have seen (and the one I own) the cutters overlap so lengthwise ridges are not an issue. Referring to this as a condition of one type of cutter and not another is a misnomer. I can make this happen on my spiral head machine or my knifed machine if I feed the material really quickly. At a good feed rate this is a non-issue.

    Obviously, only a blade running parallel to the surface it is cutting can leave no entrance and exit point. It is pretty easy to find the rate of feed on a given machine that will avoid this condition. The ideal feed rate allows the next knife or insert to remove the exit point of the previous cut thereby creating a smooth surface. If you move too quickly the entrance point is after the TDC of the previous cut and presto - you get ridges. We've all seen this condition on rough milled lumber that is really shot through the machines by power feeders.

    Untitled.jpg

    I think we are getting hung up on something that is a non-issue on a well tuned and operated machine. On the rare occasion I get in a hurry and get some detectable marks on a surface, a couple light swipes with a sanding block removes them. We're not talking washboards here like come out of a mill. I get glue ready rip cuts off my tablesaw too. Not because it is better than another saw; it is just setup and operated well (or as well as I can). If this were difficult to achieve, I sure couldn't do it . I think this is getting blown out of proportion.
    Last edited by glenn bradley; 12-24-2009 at 7:20 PM.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  11. #11
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    I don't know about you guys, but I have a spiral cutter-head on my Grizzly 6" jointer, and I have not a ridge left on any board that I have put through. It leaves a glass smooth finish on every board that I have put through. If they are there then I cannot see them. Any way it goes, I think that they are better than straight knives.

    Chuck

  12. #12
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    I just purchased a Grizzly 8" jointer and have been confused about replacing the head with a Byrd spiral too. Just looking at my own experience, I am a hobbyist and mostly use oak, maple, walnut, & some softwoods and have never had tear-rout problems with any of these on my previous 6" straight knived jointer. I also only take about 1/32" or a little more off of each pass. Then I have heard the argument that why put a spiral head on the jointer if you are going to put the wood through your planer that has straight knives? So, my thoughts are if you a hobbyist the straight knife is the way to go. Some that pass hundreds of BF of material through these tools use the insert cutters because of the ease of rotating them to get a new edge. As a hobbyist I have no problem spending an hour replacing the knives every one or two years. Also, it's hard for me to justify almost 1/2 the price of the jointer in a new cutter head.


    Good Luck,

    Mike

  13. #13
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    There is a nice review of cutter heads in Wood Magazine Feb 2006. I bought a Yorkcraft 8" jointer with a spiral cutter head that had "radiused" inserts. It leaves almost imperceptible ridges that go away after 2 or 3 passes with 180 grit sandpaper. The results are especially impressive on figured wood and I never see tearout except on the trailing 1/4" of the board. I have used the machine moderately for over 3 years and have yet to rotate the inserts, and still get the same clean cut as originally (or so it seems). If you can swing the cost differential, you won't be sorry. When I upgrade to a new planer, I will get a spiral head on that also.

  14. #14
    I simply still don't see the point of getting those expensive helical heads on a jointer for the reason that you've got to pass the wood through the planer afterwords.
    One of those heads on a planer makes a lot more sense, no?

  15. #15
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    Quote Originally Posted by Bill Borchardt View Post
    I'm getting ready to pull the trigger on an 8" jointer and I'm in the same boat as Glen. I'm trying to evaluate the pros and cons of whether to get a jointer with traditional knives or a carbide spiral cutter head.

    From what I've read here and other places here are the pros & cons:

    - Straight knives:
    -- Pro = Lowest initial cost
    -- Pro = Smooth cuts on normal stock
    -- Con = Will lose sharpness sooner than carbide head
    -- Con = New knives alignment is somewhat time consuming / difficult

    - Spiral carbide cutter heads:
    -- Pro = Better cuts on figured grain stock
    -- Pro = Carbide cutters stay sharp longer
    -- Pro = When edges get dull easy 1/4 turn on cutter to fresh carbide edge
    -- Con = Higher initial cost
    -- Con = Leaves small ridges after jointer pass across spiral cutter head

    For the carbide spiral cutter heads here's what I understand (may or may not be correct ):
    - Byrd head has carbide cutters on an angle to shear cut (most preferable) and Byrd head is considered "tops"
    - Other manufacturers have heads with "shear" angled cutters
    - Straight angle carbide cutters still do the job, but not quite as smoothly as the Byrd or angled carbide cutters
    - All carbide spiral cutter heads leave minor “ridges” after jointing operation

    Those who have more knowledge, please fire away and either confirm or correct my understandings!

    Billbo
    Smyrna, GA
    I do not get ridges with my Spiral cutterhead that was made my Grizzly. I do get ever so slight (and I mean ever so slight) scallops with the Byrd Head on my Powermatic Planer.

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