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Thread: Jet JWP-15CS Blade Apocolypse!!!!

  1. #1

    Jet JWP-15CS Blade Apocolypse!!!!

    Had this happen yesterday:
    IMG_3681[1].jpg
    For those that can't see photo's it's all 3 15" blades warped like a banana. When I bought these Powertecs I complained about the construction over on WWT.
    This was on 4/4 flat sawn oak. I've run a lot of things through that planer that I shouldn't have in the past, but never this happened. I always take 1/16 or less off per pass, never 1/8. This was about 250 feet of 4/4 6" wide red oak. What's going on here? I'm glad I noticed a problem when I did. These blades are a few more passes to a knife ejection. Not doing end or edge grain here, just face.

  2. #2
    Join Date
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    Were they straight when you installed them?

  3. #3
    Join Date
    Nov 2007
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    Columbus, Ohio
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    486
    Just a guess, but I’d suspect you didn’t have your knife locking bar tight enough. If I’m seeing the knives correctly, either just the middle of each blade was loose or, if your cutter-head has set screws on each end of the knives to level each blade, the entire length of each bar may have been loose and the leveling screws may have prevented the ends from pushing in. Unfortunately, I’d suspect those knives are toast as you will likely never get a straight edge on them again.

    Did you recently chance the knives? Did you happen to lubricate everything before putting it back together and not clean the lubricant off the mating surfaces of the blade, cutter-head, locking bar, and locking bolts/screws? Did you happen to forget to fully tighten the middle bolts/screws before closing it back up? If the knives were indeed slipping, I don’t think any knives, regardless less make, would hold up to the forces involved.

  4. #4
    Yes they were straight. Was cutting fine for the last month or so since I had them put in new. Was pushing 4/4 oak yesterday and the wood started burning. Immediately knew the cause (dull blade). Yes I thoroughly clean the entire cutter head and mating surfaces as much as I can reach (as if I was cleaning a gun). Lockbolts thoroughly torqued (but not so much to snap the blade!). I'm pretty safety conscious when it comes to tools with spinning blades, I have a check your self before you wreck your self policy and always triple check everything when ever I tune up a tool or change a blade. What looks like happened is some force, heat, or too thick pass (1/16", seriously?!?!?), or my suspect, defective steel, caused the blade to get pushed in the middle, turning up both ends. This oak does have quite a few knots, some big.

    Well aware the blades are toast, got a another set in today, taken me 4 hours to plane 6 boards at 1/2048" per pass!

    Since I've put the now bent ones in, prob put 500 ft of mostly 4/4 6" wide pine, cherry, and oak thru it.

  5. #5
    Join Date
    Nov 2009
    Location
    Peoria, IL
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    How much blade was out of the cutterhead? Did you use a factory setting gauge to set them?

  6. #6
    Yes to using the guage, to just where you can feel/hear the head of the gauge sliding across the top of the blade.

  7. #7
    Join Date
    Feb 2009
    Location
    LI, NY
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    178
    Just bite the bullet and install a Byrd/shelix head and rubber indeed/outfeed rollers

  8. #8
    Join Date
    Nov 2007
    Location
    Columbus, Ohio
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    Quote Originally Posted by Thomas Colson View Post
    Lockbolts thoroughly torqued (but not so much to snap the blade!)
    I have a 25 year old 15” Jet planer with straight blades. Maybe your cutter head is different, but I can’t see how you could over tighten the lock bolts to the point of snapping the blade. The flat faces of each of my blades is fully supported across its width and they are held in completely buy the force of the locking bar pressed up against the blade. The locking bar is “tightened” buy unscrewing the locking bolts that are threaded into it. The only thing that could break when tightening my setup could be the bolt but I’d suspect the threads would strip before that as the bolt is in compression and not tension. Does this sound similar to how your cutter head is set up?

    What makes you think the steel is defective? Unless something looked obviously out of wack with the blades before install, and if they went into the cutter head strait and they came out like bananas, I’d suspect a problem with setup rather than defective blades.

    I’ve run several thousand board feet of hardwood lumber through my planer, both skip planing rough stock, and finish planing to dimension. I routinely take deep cuts to the point of getting stock stuck by the depth of cut limiter plate on the entry of the machine (i.e. I’m cutting at least 1/8” off). I’ve never had knives overheat or move noticeably from where I set them. If your having to take 1/2048” per pass, something is set up wrong. Were the knives installed in the correct orientation and with the locking bar and locking bolts and blade in the right order?
    Last edited by Andrew Nemeth; 07-04-2020 at 4:07 PM.

  9. #9
    I believe I have the same model. It's circa early 2000's. Yes, the blades are properly installed with the lock nuts tightened, used the factory supplied gauge to set height, the blades went in straight and came out curved. I too routinely take cuts right up to the 1/8" limit, have many times in the past, I could barely detect a sound difference. It's just since I put these powertec in that I've been having problems. I've been at this all day, one suspicion I have is that this is 100+ year old oak taken from an old smoke house (no it's been denailed!). So however old the tree was when it cut, add 100 years. The grain pattern in many cases is tighter then I ever seen in oak milled the last 20 years, occasionally marbleing. I'm suspecting this wood is too hard for 40$ knives, and I'm too broke for carbide or a helix cutter. This is a DIY workshop/home reno, I'm not selling anything....but I'm still buying new tools! Another angle I'm going with is the chip breaker is so tore up and gouged it really no longer functions as a chip breaker, but I can't see how that's leaving so much saw dust in the cutter area that it's going to warp the blades.

    Before I hit the 6 pack tonight I'm gonna hone a set of Frued blades I didn't know I had and are within spec for width and throw them in tomorrow to see if I have the same problem. The freuds aren't "that" much better than the powertec imho.

    Think carbide tipped are the solution for super-hard oak?

  10. #10
    Were the knives dull when you removed them? Are the new knives already dull? If so, the steel is n.g. at least for the oak you are dealing with. I hope 1/2048" (.0005") is a typo. In any case, if you can't take a reasonable cut there is something wrong with the new knives or the setup.

    Hard to believe the knives could deflect that much if properly torqued down. Were the ends working their way out of the head, or were the centers pushed in?

    A set of carbide straight knives is not exorbitant given their performance https://template-services.com/Planer%20Knives.htm

  11. #11
    I feel like i'm taking 1/2048" for as little I'm moving the hand wheel.

    Ends came out a bit, center went in a bit. The old knives weren't dull.....sometime the planer doubles as a "nail finder" despite my two metal detectors, and eventually I get sick of sanding out the ridge, so the new knives went in in May, and came out today....bowed....

  12. #12
    Join Date
    Nov 2007
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    Where the knives ground at the proper angle to allow clearance on cut? I know you can run into problems with bevel down hand-planes if they are not ground at an acute enough angle the non edge side of the beveled surface can contact the wood before the cutting edge. While I’ve never heard of it happening on commercially manufactured blades, it is theoretically possible.

    As for carbide vs. steel for the knives, while I have never run carbide knives, I did look into them. From what I understand, carbide will not get as sharp as the edge of of most steel knives but they are more durable and won’t dull as quick. Initially, the cut should be superior with steel but the steel will dull more quickly. However, carbide is much more brittle than most steel. So, if you are planing very hard materials, and particularly a material that has a great differences in densities (like knots), you are going to be more prone to nicking your knives. When I looked into it 10 or so years ago, carbide seemed like a good solution for production shops that often require sharpening but not ideal for the hobbyist or craftsman who is looking for quality of cut and is not too concerned about the down time of getting knives sharpened. I fall in the hobbyist craftsman category. I think I also came to the conclusion that if I was going to spend money on carbide knives I would want two sets, so that I could have one set sharpened while the other is on the machine. If I was going to spend for two sets of knives, I might as well do a byrd shelix cutterhead (or another helical insert cutterhead) and be done with it. Since I don’t do crazy figured wood too often, and I’ve made it this far without, I’ve always managed to spend my money elsewhere. Now, all that being said, I’d love to hear feedback from someone who has switched from straight steel to straight carbide or vice-versa.

  13. #13
    I use carbide tipped knives in my16" jointer. It's an oddball import with no jackscrews so knife changes are a real pain. The carbide knives last several times as long between sharpening as HSS- the present set has been in use for two years and the front 2/3 is still in decent shape. I haven't had any noticeable problems with chipping milling mostly cherry and hard maple. I probably spent close to $500 for two sets of 4 knives but I saved more than the difference in cost in labor over the past 10 or 12 years (my HSS knife sets needed replacement anyway). I think the cost of a replacement spiral head would be better applied to a planer than a jointer- might be worth it to some.

  14. #14
    So up until now, here's my experience with planer knives:
    Used the 3 sets that came with it when I bought it of CL;
    Had them resharpened, 2 of the 3 came back not wide enough to reach the set screw (lesson learned!);
    Finally, the last of the original got too many nails and staples through it, ordered the powertecs.

    Two other key pieces of evidence that I thought of 4 beers deep into a 6 pack last night:
    The powertecs were unusually loud. Like holy shit my neighbors gonna kill me loud;
    The powertecs had a very high-frequency vibration when they got into the wood;
    When I put my hand on the wood coming out it was unusually hot;
    Eventually the powertecs failed.

    So I honed the Frueds up to 8000 last night, put them in this morning.

    Holy cow what a difference! So quiet I don't even need my ear muffs. In fact, I was like did I lower the cutter enough it's not making contact with the wood that's odd...only to have the smoothest piece of wood ever to come out of that planer in the 8 years I've owned it. I can balance a nickle on top when it's running.

    So here's the outcome I'm gonna go with on this:

    I took factory blades out of the box and threw them in the cutter without checking for sharpness. Up until then I've been using blades that were sharpened and honed by a professional. I never knew honing planer knives was a thing. The powertecs were essentially dull out of the box and needed a honing. The dull edge generated heat, which caused warping, which caused vibration, which caused the banshee noise.

    Lesson learned: hone your darned planer knives when you open the box!

    Now I gotta find me a honing jig. Got carpal tunnel holding those knives at angle for 2 hours.

    And here's my manifest on nails that many of you will agree with: I use two detectors, one when I'm cleaning off the wood with a wire brush to get rid of any rocks that may be embedded. Then there's one that hangs right by the planer that I use before the wood goes in. I bet this never happened to you, sometime my mind gets confused as to "Did I scan that piece of wood already"? I'll scan and plane 9 boards, somehow forget the 10th board, and EVERY SINGLE TIME if I forget to scan, a nail grows inside the 10th board......whereas if I scanned it, the nail would magically be gone.

  15. #15
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    Quote Originally Posted by Thomas Colson View Post
    ...Two other key pieces of evidence that I thought of 4 beers deep into a 6 pack last night:
    The powertecs were unusually loud. Like holy shit my neighbors gonna kill me loud;
    The powertecs had a very high-frequency vibration when they got into the wood;
    When I put my hand on the wood coming out it was unusually hot;
    Eventually the powertecs failed...
    Sounds to me like the knives were in the head backwards, and possibly not in the proper orientation with the gibs.
    Last edited by John Lanciani; 07-05-2020 at 1:17 PM.

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