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Thread: Is It The Bandsaw, The Wood, The Blade or...?

  1. #1
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    Is It The Bandsaw, The Wood, The Blade or...?

    You have the patience of a saint if you actually read all this but I thank you profusely for whatever help you can provide.

    I have a Jet JWBS-18 bandsaw with a 1-1/2 HP motor. It's primarily used for resawing boards from 3-9" wide. Most woods are African or South American in origin.

    Blades used are Lenox Woodmaster CT (1", 1.3TPI), Resaw King and the newest addition is Lenox Tri-Master (1-1/4" 3TPI).

    The Woodmaster CT resawed a bunch of 8/4 sapele with pretty good results. When I tried resawing pecky Bolivian walnut, it couldn't handle it. So I bought the Resaw King and was able to resaw up to 9" wide PBW. Maybe 100' linear feet. Since then I have used it occasionally for smaller work.

    Next resaw was zebrawood. For a neighbor. After the Resaw King failed to track, I reluctantly installed the brand new Tri-Master. After painstakingly setting it up, I ran a 48"Lx8"W piece of 8/4 to 1/4" thickness. Perfect! So we set up to resaw two 8/4 zebrawood boards. One was 6-1/2" wide, the other 8-1/2" wide. Both were about 9' long. Both had been jointed on two faces. The cut was set for a final 1/2" thickness.

    It started off fine. Then the 20A breaker tripped. So I told my neighbor to slow the feed rate. I was keeping the wood pressed to the 6" tall fence while he pushed. Twice more the breaker tripped and both times we again slowed the feed rate.

    On the last two cuts, blade drift started up. It got pretty bad so we had to flip the boards to finish up.

    Past experience tells me blade drift is caused by a dull blade, too fast a feed rate, too shallow of a gullet or a poorly aligned fence. I have the Laguna Driftmaster fence, which I have found to be unnecessary, but even incorporating those features of the fence didn't stop the drift.

    BTW, the dust collector drum was filled with a fine dust. The Tri-Master wasn't acting like a rip blade but rather finely removing the wood.

    So I'm wondering why these carbide tipped blades seem to fail so quickly? Is the motor under powered? Are the blades not designed to handle these woods at these thicknesses? Do we have to slow feed rates to a snail's pace? It takes a LOT of pressure to feed the wood as it is.

    Thoughts?
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  2. #2
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    If it takes a lot of pressure for the blade to cut, especially the 1.3 tpi CT, then the blade is dull. Simple as that. 100 ft doesn't seem like much, but if the Resaw King started drifting it must be dull, too.

    The good news is you can easily sharpen the 1.3 tpi CT. I posted here how to do it a couple of months ago. Once you've got a sharp blade you need to put enough tension on it to cut well as long as possible. I recommend 25 ksi assuming your saw can muster it. I you aren't measuring blade tension I recommend you do to verify your saw is capable. If it's not, go with a narrower blade. A 3/4" blade works fine for resawing even 12" stock. I doubt your saw can tension a 1-1/4" blade. If it's robust enough to tension a 1-1/4" blade it most likely would have more than 1.5 HP to drive it.

    As for HP, 1.5 isn't much for resawing, and that may be contributing to what may be premature blade wear. My rule of thumb is you need 1 HP for every 3 - 4 inches of resaw height, so 1.5 HP is good or about 6 - 8". Dense, hard wood is going to take more HP, and so is the aggressive tooth of the 1.3 tpi CT. You are probably best off with the Resaw King, and it sounds like you cut the most square feet with it before it dulled.

    Sharp blade, 25 ksi, and probably 2 or 3 tpi to better match your available HP. Good luck.

    John

  3. #3
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    Julie, you sound like you know what you are doing in the set up, but the blades are new and should not be acting as if dull so quickly. I can get a really excellent resaw off a freshly sharpened 1/2” bimetal blade, but prefer to use a Lenox carbide 1” Woodmaster CT because it is even better. In other words, it really shouldn’t be the blades you are using.

    It shouldn’t be you either, but the presence of dust makes me wonder if the blades are installed the right way around! Only partially kidding

    That leaves the machine. It appears that the blades are each not holding tracking for more that one or two cuts. I wonder if you have enough tension on them? It would make sense that they need the very nth degree if sharpness to track if under-tensioned, but then the woods you use, while abrasive, should not dull a carbide blade for a long, long time. Perhaps there is something going on with the guides? They may be loosening up after a very short time, and each time when you change blades they are reset. That is where I would look. That and ensure the CT, especially, has enough tension.

    Regards from Perth

    Derek

  4. #4
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    I've never used a Resaw Master, but the most common statement is the amazing surface finish. To me that indicates very little set in the tooth. For doing a lot of resawing, I use blades from sawmill supply houses. I use 3/4" wide blade with 3/4 tooth pitch. That's a tooth every 3/4". Lots of set produces a rough surface, but very efficient cutting speed. Exotics can have a lots of properties not found in domestic wood. You can see mica specs, waxy feel, and high oil content. All can make high production and tool life an issue.
    Last edited by Richard Coers; 02-20-2021 at 9:52 PM.

  5. #5
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    I have the same saw, and use mine only with a 1/2" 3 TPI blade. This seems to work fine for resawing cherry and walnut up to 9" wide or so, but I am not trying to resaw 9 foot boards, just pieces long enough to make guitars and such. I resawed some 2" wide zebrawood the other day and it cut very easily, but I was just making banjo fretboards so much less of a load than your situation. I would try a narrower blade that you can get tight and see how that goes.

  6. #6
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    I'd bet it's the wood's wear on the blades that is causing the drift and the difficulty feeding it/ premature wear.
    Ken

  7. #7
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    I’m pretty sure your problems lie with the saw and blade choice.

    That saw is is underpowered for the dense hardwoods you’re resawing. 2nd , you are using waaaaaay too wide of a blade for that machine ; especially at 1- 1/4”. No way that saw can tension a blade that wide. None. Derek is already wondering this. John concurs.

    Sapele is pretty hard, not sure on the pecky walnut, but zebrano is wicked hard. I’m not surprised you threw a breaker on a 9’ x 6” cut.

    I’m guessing 3/4” carbide is about the max youR saw will reliably tension properly. I’d also ditch 3 tpi blades for exotics too.

  8. #8
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    Quote Originally Posted by John TenEyck View Post
    If it takes a lot of pressure for the blade to cut, especially the 1.3 tpi CT, then the blade is dull. Simple as that. 100 ft doesn't seem like much, but if the Resaw King started drifting it must be dull, too.

    The good news is you can easily sharpen the 1.3 tpi CT. I posted here how to do it a couple of months ago. Once you've got a sharp blade you need to put enough tension on it to cut well as long as possible. I recommend 25 ksi assuming your saw can muster it. I you aren't measuring blade tension I recommend you do to verify your saw is capable. If it's not, go with a narrower blade. A 3/4" blade works fine for resawing even 12" stock. I doubt your saw can tension a 1-1/4" blade. If it's robust enough to tension a 1-1/4" blade it most likely would have more than 1.5 HP to drive it.

    As for HP, 1.5 isn't much for resawing, and that may be contributing to what may be premature blade wear. My rule of thumb is you need 1 HP for every 3 - 4 inches of resaw height, so 1.5 HP is good or about 6 - 8". Dense, hard wood is going to take more HP, and so is the aggressive tooth of the 1.3 tpi CT. You are probably best off with the Resaw King, and it sounds like you cut the most square feet with it before it dulled.

    Sharp blade, 25 ksi, and probably 2 or 3 tpi to better match your available HP. Good luck.

    John
    Thank you, John.

    I followed Matthais Wandel's advice on sharpening the Woodmaster CT. Must have done a poor job, though. I'm sending to Dynamic Saw for professional sharpening. The Resaw King, too.

    The manual for the Jet JWBS-18 says it can handle up to 1-1/2" wide blades. I always tension past the gauge on the saw when resawing. Press testing on the side of the Tri-Master, it gave very little. Since that first test cut went so well, I figured the tension must be good. My neighbor has little woodworking experience and can be a bit of a beast (as in, "Muscle overcomes all difficulties") and I had to remind him several times to ease back on the pressure. But even he was beat after we finished resawing the first two boards. And there are two more to go. He now wants to rip the edges on the table saw and let the bandsaw finish the rest. Probably a good idea.

    Not much I can do now about the 1.5HP now. But I thought I ordered 2/3 TPI on the Tri-Master. That 3 TPI blade requires certainly produces a lot of fine dust. Never seen that before.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  9. #9
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    I would be suspect of tension too.

    Maybe you could try a 1/2 3TPI bimetal blade and see how it does? If it works then perhaps a 1/2 3TPI carbide would the long term winner?

    Full disclosure: I don’t have much experience with carbide blades, I bought a used Agazzani that came with a resaw king, I’m pretty sure that blade was toast when I got it because it never cut well. Laguna wasn’t very helpful when I called for advise so if I ever go the carbide route again it’ll be a Lenox wood master CT.

    And I still need to make John’s tension gauge!

  10. #10
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    Quote Originally Posted by Derek Cohen View Post
    Julie, you sound like you know what you are doing in the set up, but the blades are new and should not be acting as if dull so quickly. I can get a really excellent resaw off a freshly sharpened 1/2” bimetal blade, but prefer to use a Lenox carbide 1” Woodmaster CT because it is even better. In other words, it really shouldn’t be the blades you are using.

    It shouldn’t be you either, but the presence of dust makes me wonder if the blades are installed the right way around! Only partially kidding

    That leaves the machine. It appears that the blades are each not holding tracking for more that one or two cuts. I wonder if you have enough tension on them? It would make sense that they need the very nth degree if sharpness to track if under-tensioned, but then the woods you use, while abrasive, should not dull a carbide blade for a long, long time. Perhaps there is something going on with the guides? They may be loosening up after a very short time, and each time when you change blades they are reset. That is where I would look. That and ensure the CT, especially, has enough tension.

    Regards from Perth

    Derek
    Thanks, Derek. As I said in the first post, the Woodmaster CT really performed well on sapele. And that was my go-to resaw blade for the last 7-8 years. But it's probably dull now. The Resaw King hasn't been used all that much. I resawed sipo mahogany for some guitar sides and for a few other projects. And then there was the pecky Bolivian walnut. That stuff has hardened resin in it that can chip off and get caught in the cut. I thought that may have been the culprit, if in fact the blade is dull.

    On to the machine... When I was setting up the Tri-Master, the blade seemed to be tracking properly on the wheels. Of course, what is "properly"? There seems to be some different schools of thought on that. I had for years simply centered the blade on the wheel. But then I saw a video (can't remember his name but he does demonstrations for setting up bandsaws). IIRC, he said to lay the teeth slightly ahead of the crown of the wheel. I haven't tried that so the Tri-Master was set up centered on the wheel.

    After we were done, I opened up everything to clean it out. I found the blade fairly far forward on the wheel, with the teeth almost to the edge of the wheel. Did it fall out of alignment due to over-tension or was it from applying so much pressure in the feed or did I just fail to recheck it after setting it up? I don't know but it concerns me.

    As for the guides, I'm not all that crazy about them. They are the type where the flat side of the wheels press against the side of the blades. There have been times when the top ones have loosened and ended up clamping down on the blade and stopping it cold. That rarely happens now because I've learned to seriously tighten the guides and leave more space than I used to. But that leaves some slop. Maybe it's time to pop for a better guide set.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  11. #11
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    I just checked on the bandsaw again to see if what I wrote above was accurate. It wasn't. The teeth of the blade were actually protruding past the outer edge of the wheel. After fixing that, I checked the tension again. It seemed loose. Could the new blade have stretched a bit? Anyway, I tightened it again and reset the guides. I have a short piece of zebrawood here (my neighbor has the rest for sanding) and I'll see how that goes. It's about 6" wide but probably too short to see if there is drifting. But it will be interesting to see if all I get is fine dust. That shouldn't be.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  12. #12
    As a point of comparison, try a steel tooth blade in the 1/2-3/4” range. My guess is you will see significant improvement in the ability to tension these blades on that saw, which will lead to a completely different resaw experience. In my experience, blade deflection is a huge consumer of power.

    Brute power is only one factor in any machine’s performance. I doubt it’s the weakest link in solving your resaw woes. I would address the blade tension first and this likely means using a narrower blade.

    As I understand it, maximum blade width refers to the wheel and guide capacity rather than the saws ability to tension. A properly tensioned blade with sharp teeth solves a lot of problems.

    I imagine the blades you are using are not failing quickly, but rather exposing the limitations of that particular saw’s ability to tension and power the blade past a point of optimal performance. Meaning, once initial blade sharpness declines slightly there is not enough tension and horsepower to overcome it. Our natural inclination to push harder probably don’t help with blade life either.

  13. #13
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    Only the rear guide bearings have any great impact when resawing, and with enough tension even they aren't needed much. The side guides are there for cutting curves; if you need them to cut straight then something else is wrong and it's usually low tension and/or a dull blade.

    Rather than guessing at the tension buy or build a tension meter and find out what it really is. I'd bet money that saw cannot put 25 ksi on a 1-1/2" blade, and seriously doubt it can do it on a 1-1/4" one. But the only way to know is to measure it.

    Blades don't permanently stretch unless you exceed the elastic limit of the steel which isn't going to happen. If the blade is moving on the wheels, especially forward, then the tracking wasn't set up right or something moved or bent during use.

    You can tell if a blade is dull by visual inspection. Get a magnifying glass and look at the corners of the teeth. You should see a sharp corner. If instead you see a flat spot, it's dull. A sharp blade will catch the back of your fingernail; a dull one won't.

    With the info. available, I would focus on 3/4" or narrower blades like the Resaw King. It's thinner than the other carbide blades which will result in higher tension and also help the 1.5 HP motor do its best.

    John

  14. #14
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    Quote Originally Posted by John TenEyck View Post
    With the info. available, I would focus on 3/4" or narrower blades like the Resaw King. It's thinner than the other carbide blades which will result in higher tension and also help the 1.5 HP motor do its best.

    John
    I have to admit I'm not all that impressed with the Resaw King. That's the blade we started off with on the zebrawood. It hadn't been used all that much prior. As I mentioned before, the only wide boards I resawed with that blade were sipo and pecky walnut. I'd be surprised if I ran more than 100 linear feet of wide boards and not much more of narrower boards.

    I checked the corners of the Resaw King tips and they look pretty square. However, they didn't do so well with the fingernail test. On freshly sharpened edges, I can feel the edge shaving off the nail. This I hardly felt. And there was very little nail shaved off. So I guess it's dull. That's pretty disappointing that it should have dulled so quickly. I think I paid something like $275 for that blade. I only paid around $900 for that saw, brand new. But that was maybe 20 years ago.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  15. #15
    Might there be evidentiary value in resawing some wider poplar and perhaps maple or cherry. The woods shouldn't be too expensive and the experience might shed some light on the issue(s).

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