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Thread: Helical cutterhead difficulties

  1. #1

    Helical cutterhead difficulties

    I'm finding is near-impossible to properly seat the carbide cutter inserts on my
    Grizzly G0856 8-inch jointer. It seems that no matter how careful I am to clean the
    carbide inserts and the cutterhead body and apply the recommended torque to the installation screws, the
    net result is a poorly jointed surface. In mild cases, the surface is slightly wavy (undulating a few thou
    across the board), while in other cases there are clear ridges left behind by some of the inserts.

    It seems obvious that the inserts are not seating properly. In fact, it appears that the angular orientation of the inserts is not repeatably registered. Slight variation of the applied torque to the screws can result in slight rotation of the insert. Even when I tighten to the same torque repeatedly, slightly different orientations of the inserts can result. The effect is small, but you can see it by eye and the jointed surface reflects this variability.

    Is there some magic to the installation of the inserts? Have others seen similar problems? Is this
    a Grizzly issue, or just an incompetent user?

  2. #2
    Join Date
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    Sorry to hear.

    When I had an 8" grizzly helical jointer every pass seemed to leave a glass smooth finish. I upgraded to a 12" laguna and I get the ridges on every pass now. Sam from Minimax recommends the straight blades because of this. He calls the ridges "ghosting" and that's why he recommends straight knives over helical, no matter what brand. I don't have enough experience to tell you how to fix it, but I notice it as well.

  3. #3
    Join Date
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    Quote Originally Posted by Jim Eisenstein View Post
    I'm finding is near-impossible to properly seat the carbide cutter inserts on my
    Grizzly G0856 8-inch jointer. It seems that no matter how careful I am to clean the
    carbide inserts and the cutterhead body and apply the recommended torque to the installation screws, the
    net result is a poorly jointed surface. In mild cases, the surface is slightly wavy (undulating a few thou
    across the board), while in other cases there are clear ridges left behind by some of the inserts.

    It seems obvious that the inserts are not seating properly. In fact, it appears that the angular orientation of the inserts is not repeatably registered. Slight variation of the applied torque to the screws can result in slight rotation of the insert. Even when I tighten to the same torque repeatedly, slightly different orientations of the inserts can result. The effect is small, but you can see it by eye and the jointed surface reflects this variability.

    Is there some magic to the installation of the inserts? Have others seen similar problems? Is this
    a Grizzly issue, or just an incompetent user?
    I had a similar issue ages ago with an 8" Griz. Are you rotating or replacing? My situation may have been different as I was replacing, turns out they were slightly proud of the cutters that came on the original head.

  4. #4
    I should have clarified that when the jointer was new (~1.5 years ago) it produced good surfaces. At some point one
    insert started producing ridges. I tried rotating it, but that did not solve the problem so I replaced that one insert. The
    remaining 35 are rotated versions of the original inserts. So the machine can work well, but my fiddling with the inserts
    has upset it somehow.

  5. #5
    I’ve experienced the exact same issues with a Byrd head in a Dewalt 735 planer in a shop I worked in at the time. Extremely sensitive to misalignment and really easy to get things wrong when rotating. I spent most of an entire work day once re-dialing the cutterhead back in after a rotation of some of the cutters. I found that cleaning the area where the cutter seats of pitch/dust build up with a soft but somewhat abrasive brush and degreaser helped matters at some point. I also recall a couple of areas that had some tiny broken bits of steel preventing the proper seat of the rotated cutter which took some time to realize and find. I still never got it cutting as it was from the factory but at least got rid of 95% of the ridges and non flatness.

    Im sure some of the heads are better than others but I would take a Tersa or Terminus head over a Byrd head any day and twice on Sunday. I actually have one in my jointer and am always happy with it and love 5 minute knife changes.
    Still waters run deep.

  6. #6
    Thanks, Phillip. Glad to hear that I'm not totally crazy. I was very careful about cleaning the inserts and cutterhead body, but from what you say I may need a microscope to find tiny shards of metal! I've also seen that it's easy to seat the insert slightly misaligned in angle. I'd have thought the machining tolerances would be tight enough to prevent this.
    Definitely puts the lie to the sales pitch for how easy it is to rotate/replace the cutters. Also, thanks for the tip on Byrd; I'd been thinking about getting one!

  7. #7
    First off, I do not have an insert cutterhead in my jointer or planer but I do have one for my shaper. One very important thing IMO to check is to insure that the cutters are machined exactly the same. If one is off ever so slightly it would have a tendency to cut deeper or shallower based on logic. If I was trying to diagnose this situation, I'd get out a dial indicator and magnetic base. set up a fence across the outfeed table to insure comparable setting while checking the cutters, then slowly rotate the cutterhead backwards and check the height of each insert.
    I don't have an easy way to check the mounting point on the cutterhead to insure they're all machined the same.
    Good luck

  8. #8
    Join Date
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    I've come to the conclusion that helical cutter heads can be more trouble than they're worth. The issues discussed in this thread are by no means uncommon. About the only thing that would drive me to switch is if I regularly worked with extremely hard/abrasive wood that destroys HSS knives.

  9. #9
    Sorry to hear of your problem; I think the problem may be that you've got a slightly galled seat under the insert- and it can simply be the first thread is a little streached under the insert, holding it up just enough to produce that ridge. It's a problem I encountered with a shaper head, a hand countersink fixed it.
    I have straight knife heads in my planers and jointers, never cared for the cut from a helical head. You can't joint the cutters on most of the helical insert heads, and even OEM inserts can vary in size. Most of the replacement heads are a sideways move at best, just to save setting knives. As for abrasive stuff, I have carbide tipped knives for that.

  10. #10
    I just rotated mine on a felder ad941, no issues and have never experienced ridges like you describe. I canít imagine a better finish off a machine except for a widebelt

  11. #11
    Quote Originally Posted by Jim Eisenstein View Post
    I should have clarified that when the jointer was new (~1.5 years ago) it produced good surfaces. At some point one
    insert started producing ridges. I tried rotating it, but that did not solve the problem so I replaced that one insert. The
    remaining 35 are rotated versions of the original inserts. So the machine can work well, but my fiddling with the inserts
    has upset it somehow.

    when you replaced the one insert did the ridge in that spot go away? And when you rotated the 35 was it all good or were there ridges?

    I have always wondered if on the inserts if the edges to the right or/left get worn some just by the chips that are being cut, Iíd imagine they must somewhat but whether or not it cause issues I donít know and some the heads like the non helical byrd head has those cutters essentially on a post with all 4 edges exposed.

  12. #12
    Quote Originally Posted by Bryan Hall View Post
    Sorry to hear.

    When I had an 8" grizzly helical jointer every pass seemed to leave a glass smooth finish. I upgraded to a 12" laguna and I get the ridges on every pass now. Sam from Minimax recommends the straight blades because of this. He calls the ridges "ghosting" and that's why he recommends straight knives over helical, no matter what brand. I don't have enough experience to tell you how to fix it, but I notice it as well.

    I am surprised Sam would say that about the scm helical, i can tell you that it does not happen on the Felder helical

  13. #13
    Thanks, Paul. I am in the process of using a dial indicator to do something like what you say. As I mentioned in my first post, the angular orientation of some of the cutters is slightly dependent on
    how you torque the screws. I'll try to be more quantitative in a later post.

  14. #14
    Join Date
    Aug 2021
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    Redmond, OR
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    Quote Originally Posted by Frank Pratt View Post
    I've come to the conclusion that helical cutter heads can be more trouble than they're worth. The issues discussed in this thread are by no means uncommon. About the only thing that would drive me to switch is if I regularly worked with extremely hard/abrasive wood that destroys HSS knives.
    This thread has been an eye opener for me too. I have often contemplated changing the heads on my 15" planer and 8" jointer to a Byrd type head. The ease of rotating a single carbide cutter when there is a chip in the cutting surface was a big draw for me. Now... hmmm...

  15. #15
    Quote Originally Posted by Michael Schuch View Post
    This thread has been an eye opener for me too. I have often contemplated changing the heads on my 15" planer and 8" jointer to a Byrd type head. The ease of rotating a single carbide cutter when there is a chip in the cutting surface was a big draw for me. Now... hmmm...
    Helical heads are said to deal with figured wood better, but the potential for misalignment is off-putting. I have noticed the wiggle factor on my shaper chiclet cutter, though haven't had a problem. Tersa is pretty much idiotproof. Maybe carbide Tersa knives coupled with a supersurfacer?
    Last edited by Kevin Jenness; 01-06-2022 at 4:37 PM.

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