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Thread: Anybody have success with a "magnetic knife setting jig" for a jointer?

  1. #1
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    Anybody have success with a "magnetic knife setting jig" for a jointer?

    I bought a used 6" Jet jointer some time ago, and it's the 40th anniversary addition, so it's was made sometime around the late 90s. The jointer is actually in like new shape, doesn't appear to have much use. Anyway, it came with a patented "Magnetic knife setting jig" for Jet 6" and 8" jointers. It's in my shop, but I pulled up a picture off the internet of what it looks like:
    image.jpg

    On the box it says that this jig is accurate to .001". I never changed blades yet or even use the jointer, so I've never tried it. From some research, and from the Robert Vaughn (or whatever his name is) knife setting video, I heard these jigs don't work, because the blade rises when you tighten the screws. I question this though, because like I said, this is a Jet patented product (no longer produced) and claims to be accurate within .001". Anyone have experience with these?

  2. #2
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    I use one. The blades do sometimes want to shift up. I use a feeler gauge between the outfeed table and the jig to spot this problem, then re-align the blade and carefully snug the screws again.

  3. #3
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    I have one like that and tried to use it on more than one occasion. Unfortunately, I had too much trouble with it, so I got one of these:
    http://www.amazon.com/Oneway-2289-Mu.../dp/B0002SA98I

    No comparison.
    I am never wrong.

    Well...I thought I was wrong once...but I was mistaken.

  4. #4
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    "this is a Jet patented product (no longer produced) and claims to be accurate within .001"."

    "No longer produced" is a user comment all by itself.
    - Beachside Hank
    Improvise, adapt, overcome; the essence of true craftsmanship.

  5. #5
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    I never got good results with it. But to be perfectly honest, I never got good results with any method before getting segmented carbide knives.

  6. #6
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    image.jpg

    This is is the specific jig

  7. #7
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    Just use a small, straight strip of hard wood. I use Boxwood, or Hard Maple about a quarter by three quarters. Put a knife in just tight enough with the end screws to hold it in place, but allow it to move with some pressure. Start with a knife just a little high, and push it down with the wooden strip. Swing the head back and forth until you can just barely feel the knife brushing the strip of wood over the end screws. Tighten and try with the feeler strip once you think it's right. Once the end screws are tightened, hit the middle screws. This goes really quickly once you get a feel for it.

    A lot of instructions call for setting the blades a few thousandths high, so you get more wear between sharpenings. To me, that's what an adjustable outfeed table is for.

    Once you do this a few times, it goes so quickly that it's no issue at all. I'll take the blades out, and either sharpen them, or swap them when starting on a new job.

    I have one of those magnet things somewhere, but haven't used it since the first time some decades ago.

  8. #8
    Powermatic used to sell a jig similar to the one Harold linked to. It did not have a dial indicator on it, just a lever with a small dial, but it sat on the outfeed table, and you just used an allen wrench to move the blade up or down, and tightened the set screws. Setting blades on the old Powermatic jointers with that gauge was a breeze.

  9. #9
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    I have that Powermatic dial indicator too. It taught me the trick to using a strip of wood. You still have to swing the head back and forth to find top dead center. It's faster to do it by feel only, than to use the dial, and the wood won't leave a dull spot on a blade. The strip of wood also is what you need to push the blade in, right there in place. I took the jack screws out of all my jointer heads. They were a good indicator if you put the same blade back in the same spot, but when changing to new blades, they were just an extra bother.
    Last edited by Tom M King; 08-18-2014 at 7:30 PM.

  10. #10
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    +1 to what Tom said.

    I was using the strip off wood method, but thought I oughta go high-tech so did the dial thing - very frustrating - went back to the wood strip... Peach's n cake. And this was for a 16" jointer.
    I got cash in my pocket. I got desire in my heart....

  11. #11
    I've found the magnet jigs for planers and jointer work best if gibs and knives are both cleaned and then coated with oil.
    Then I can adjust a gib bolt on each end to where knife will move but not have any rocking. I like to make a reusable jig
    to freeze head at TDC. Piece of tape on magnet prevents any damage to knives. Leaving the knives a bit too high is often
    reccommended but makes the jointer cut a convex rather than straight edge. Many of us pick and choose knife setting tips
    until finding a combination we like. If the mfg of magnet jigs didn't overstate ease of use ...nobody would buy them.

  12. #12
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    I guess the strip of wood eliminates the need for a dial indicator... If I really need one Ill buy it, but even the cheap ones aren't cheap. The "cheap imported" one that Robert Vaughn uses he said he got for $25, and I looked up that exact one and now it's around $100 with the base. I believe the video was made in 1984, so I guess that's inflation

  13. #13
    Wood Whisperer did a review of several knife setting jigs a while back. I've had good results with a dial indicator with a jig like this: http://www.woodmagazine.com/woodwork...djustment-jig/ BTW, I've found a great source for rare earth magnets are worn out Sonicare toothbrush heads.

  14. #14
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    I've used those jigs, glass with magnets, dial indicator, but the only way I have success is with a ruler.
    I adjust the knives to move the ruler 1/8", call it a day, and adjust the out-feed table up a tad.
    Never, under any circumstances, consume a laxative and sleeping pill, on the same night

  15. #15
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    With the strip of wood, as you swing the head back and forth, you can see where the TDC is as it lifts the strip off the outfeed table. Use the wood to push it down to level at TDC until a rock of the cutter head allows you to feel the knife brush the wood without lifting the strip, tighten the end screw it's over just enough to hold it in place, but still allow the other end to move as you did the first end. A lot of this is feel, but it comes very quickly. I keep the wrench in my right hand, which also moves the cutterhead. I'll bet money I can set a knife in 15 seconds without getting in a hurry.

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