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Thread: How to determine when blades should be changed or sharpened?

  1. #1
    Join Date
    Dec 2006
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    Quad Cities, Iowa
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    323

    How to determine when blades should be changed or sharpened?

    I am aware this question makes me sound like I started WW last week but that really isn't so. You could easily answer this question with "Well it depends", which is obviously true. I stopped doing much WW a few years ago and jumping back in. I don't remember when some blades were last changed or sharpened. When I buy new blades I buy good ones because cheap cutting tools steel is false economy IMO. Overly cheap anyway. Here is where I am assessing my blades.

    Tablesaw- A Forrest WW2 and a Lietz that came with my Craftsman Hybrid. I think they have a few months left in them. They have been resharpened once. They don't look damaged and cut about as well as I remember.

    Bandsaw- Rikon 14"- This one is a big mystery to me. I have blades that appear completely OK to me, but they do not track that well during resaw and they used to for sure. It's possible saw is not adjusted correctly but it's not for lack of trying. I am fairly convinced they need to hit the trash.

    Planer- I have a 15" Grizzly. It has original blades and I have no idea how to tell if they need replaced.

    Jointer- I have a 6" Craftsman Professional. It is highly likely the blades are shot thought they appear physically OK to my eye, and finger tips. I am going to put some work into setup. I have been watching some Vids and it appears I need a quality straight edge for this task. MAchine performance is poor IMO.


    Miter saw- I have a Dewalt 12" and believe I can tell it is cutting fine. Even with fairly economical blades.

    If you have further questions ask away. I didn't want to write a novel in my O.P. And thanks in advance. I'll buy what I need to, but don't have funds to waste anymore.
    Last edited by Dewayne Reding; 01-12-2018 at 2:11 PM.

  2. #2
    Join Date
    Feb 2009
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    On my 14" Grizzly bandsaw, a wandering cutline is how I tell when the blade needs to be replaced. I pretty much exclusively use 1/2" Woodslicers. Initially the blade will start wandering during resaw, and maybe only slightly, but by the time it REALLY needs to go, it will cut wavy even when cutting 3/4" thick hardwood. The fact that the waviness can be somewhat mitigated by slowing down the feed rate proves further that the issue is a blade that's not as sharp as it used to be.

  3. #3
    Round saw blades: When they start to burn. I'm sure you - like me - have pushed enough through your saws to know by FEEL when the blade's little long in the tooth, though. I always use them longer than I should.

    Planer/Jointer: Nicks in the blade cause ridges. I'll even let these go without much concern because they come off with a block plane. When straight knives are truly dull, I get more tear-out than typical.

    Bandsaw: I am most active about replacing my blades here, because letting them go too long means a bowed cut or unnecessary force during a resaw. If your blades have a high tpi count (>3) then your problem may be the type of blade. Bandsaws are the finnickiest of my machines because you're supposed to get the tension and guides set just so. But a new, proper blade will tolerate a less than perfect set up on those fronts.

    I replace my bandsaw blades when they start to require effort to push through.

  4. #4
    Join Date
    Dec 2006
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    Quad Cities, Iowa
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    Quote Originally Posted by Victor Robinson View Post
    On my 14" Grizzly bandsaw, a wandering cutline is how I tell when the blade needs to be replaced. I pretty much exclusively use 1/2" Woodslicers. Initially the blade will start wandering during resaw, and maybe only slightly, but by the time it REALLY needs to go, it will cut wavy even when cutting 3/4" thick hardwood. The fact that the waviness can be somewhat mitigated by slowing down the feed rate proves further that the issue is a blade that's not as sharp as it used to be.
    Thanks. That is the BS blade I have now. I will order a new one. I put a 3/4 Timberwolf on and it cuts straight, but it is very wasteful with the wide kerf.

  5. #5
    Join Date
    Dec 2006
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    Quote Originally Posted by Prashun Patel View Post
    Round saw blades: When they start to burn. I'm sure you - like me - have pushed enough through your saws to know by FEEL when the blade's little long in the tooth, though. I always use them longer than I should.

    Planer/Jointer: Nicks in the blade cause ridges. I'll even let these go without much concern because they come off with a block plane. When straight knives are truly dull, I get more tear-out than typical.

    Bandsaw: I am most active about replacing my blades here, because letting them go too long means a bowed cut or unnecessary force during a resaw. If your blades have a high tpi count (>3) then your problem may be the type of blade. Bandsaws are the finnickiest of my machines because you're supposed to get the tension and guides set just so. But a new, proper blade will tolerate a less than perfect set up on those fronts.

    I replace my bandsaw blades when they start to require effort to push through.
    Thanks Prashun. That was helpful. The round blades seem easier. When they stop making ultra thin veneer the time is near. I've not seen much burning so I am probably sharpening them in time. My bandsaw blade is noticeably worse by all measures mentioned in this thread. It must be time to discard.

  6. #6
    Join Date
    May 2014
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    Alberta
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    I read an article somewhere once where the guy who wrote it used a 6x loupe to look at the tips of his blade teeth on carbide tablesaw blades. I just go by feel of effort required to push thru saw and cut quality.When it gets harder to push and the cut begins to show signs of burn marks it is time for me. Jointer and planer are the same ,sort of ,ridges show up and feed effort is harder,cut quality diminishes.Time to swap in the next set of blades. With my planer I can tell by the sound,it "grunts" a bit louder. Bandsaw agree with everyone else above when the cut gets wonky and it is harder to push ,time for a new blade. Now that I reread some of the other posts just go with what Prashun said . He basically nailed it.

  7. #7
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    I also tell by feel of a cut when a blades is getting dull and generally my first step is to clean the blade, usually that significantly improves performance. I work mostly with red oak, maple, yellow poplar and cherry. Very little softwood crosses my saw table so I don't get a lot of pitch buildup. Even so there is some build up cutting hard woods. My blades are predominantly Freud blades.
    Lee Schierer
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  8. #8
    Dull tools are a lot LOUDER than sharp ones.

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