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sharpening bandsaw blades

john lucas

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I don't normally sharpen my blades. I buy really cheap ones from my local saw sharpening service so it's kind of a waste of time. I buy 163" 1/2" blades for $12 so I usually just toss them. However I dulled the blade badly cutting a log of green walnut and it was late Friday and I needed to cut some more before Monday. so I tried a couple of things. First I simply jointed the tips of the teeth. I simply ran the saw backwards by hand and held a diamond hone against the teeth. to test it I resawed an 8" piece of 2x8 pine. It seemed to cut fairly straight now but left a rippled surface.
Then I went in and used a diamond chainsaw sharpening cutter in my dremel and sharpened the gullet of each tool. That's 460 teeth so it took a few minutes. I put a piece of tape of the blade so I new where i started and sharpened all the gullets of teeth that were angled right. Then went back and did the left facing teeth and then the center teeth. Don't know if it would have been easier to simply cock the dremel and sharpen each tooth as i go instead of doing all the ones pointing in the same direction. Anyway, when I did the resaw test it cut very aggresively but still stayed straight. It left a very noticeable ripple pattern that would not be good for resawing veneed but the speed of the cut would be good for cutting green wood.
I went back and jointed the teeth again this time using an old oil stone and spinning the wheels quite a few times. The cut was very slow when I did the test but left a very clean even surface. So it seems to me if you just want to cut green wood sharpen the gullets. Don't mess with jointing the blade. If you want a better quality cut for resawing veneer then you probably need to do both.
Anyone else sharpen and if so what technique did you use. Ideally of course just buying a good quality resaw blade is the way to go but then I would not use that for cutting green wood. Too easy to get a catch and bend that good blade which is why I use the really cheap ones.
 
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Having limited time in the shop, I always try to have sharp blades in reserve. That sounds like a lot of work on a $12 blade John!! That being said, thanks for sharing as a reminder for me to get a new 1/2” carbide tipped blade for back up!!
 

john lucas

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I just checked the teeth with a 10x power magnifier. The front of the teth are flat from excessive pointing. You probably only need light pressure and maybe just 1 or 2 rotations of the blade. So I decided to sharpen the gullet again to shorten this flat area a d to see if my idea of sharpening the gullet only produces a more aggressive cut. So I sat down and tried the technique ot sharpening every tooth on one rotation. I cleaned the blade with a wire brush and then put a piece of white paper behind the blade. 5his made it much easier to see what direction the teeth were set. The I would simply set the router right then left then straight, move the blade and repeat. Only took about 5 minutes to.donall 460.teeth. it did not leave as smooth of a cut as before but cut more aggressively. Much better for cutting green wood. When it gets dull again I will try it without jointing the blade and see if it gets more aggressive which I think would be better for green wood if the blade doesnt wander.
You can see on the left the ridges left when I ground the gullet without jointing. The photo on the right was filed and then jointed. A much smoother cut but very slow cutting.
 

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I only sharpen my low tooth count blades - typically these are 1/2 or 5/8" blades with a 3/4 tooth count. Simply use a dremel in each gullet. Have not tried jointing teeth or even changing angle on the dremel, it is always at 90 degrees to the band. Rather than tape, I indicate the starting point with a sharpie, same as I do on chainsaws.

It only takes a few minutes to sharpen all the teeth on the 114" blades my old 16" WT saw uses. Find that the cut quality and speed are noticeably improved after sharpening, but I'm sure that there is room to be more scientific in my approach and get even better results.
 
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Well, I have a local shop to do it for me. I had tried the 'run it backwards with a diamond hone on the teeth' method and didn't notice any difference at all. If I was going to use a dremel, I would want a small diamond bit, about the same size as the gullet on the teeth, and some what slower speed rather than full on. I would also want to make some thing to hold the dremel level because I would expect my hand work to be pretty unsteady, and that would make a huge difference. I know set is important, especially if you are cutting green wood.

How do you 'joint' the teeth? Familiar with that term for flat work, but not for saw blades. Tops of teeth? sides?

I have noticed, years ago, that black walnut, especially when green, was really hard on sharp edges, on all of my tools from bandsaw to chainsaw to gouges and scrapers. No clue as to exactly why. I am guessing that part of it is the acidity of the wood. Another reason why I like the bimetal blades from Lennox.

robo hippy
 

hockenbery

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I don’t often sharpen blades. unless I forget to order new ones.
with the blade off the saw I hit the top of each tooth against the edge of the grinding wheel (120-180 git) with the platform on level.
if the teeth have a set I do the teeth pointing down then turn the blade inside out and do the other teeth which will now point down..

i don’t do anything to the gullets.
this gets a 3tpi blade blade sharp enough to cut green wood.
 

john lucas

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Reed. Jointing the teeth is a hand saw sharpening term. You run a file or stone over the top of the teeth leveling them so they all.cut at the same time. After that you file each tooth until its sharp.
 
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I basically use my 14" bandsaw for cutting smaller bowl blanks, not for fine woodworking, so I use a 3 TPI 1/2" blade for wet wood cutting, wide set on it, and I have sharpened a band or two if it gets dull.

I use my Dremel to sharpen, start at the weld and work my way around by just touching the top of every tooth and at 90 degrees, works just fine for me.

Sharpen bandsaw blade.jpg
 

john lucas

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That's how my friend John K Jordan does it. That's sort of what got this started. I wanted to see if there was a better way. When I dull this blade again I'm going to do exactly what you just wrote and see if it's any better or at least the pros and cons.
 
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Lennart ......That is totally cool. What an idea and what a neat tool.

What I have found is that about the time my band saw blade gets really dull, it is just time to put on a new blade.
I have sharpened them using a Dremel tool and it works........but I find that the weld on the blade is getting weak about the same time the blade becomes dull. About three cuts after I have spent 15 minutes sharpening the blade.....the blade breaks. So, I always try and keep a new one hanging on the wall to just replace the dull one.
 
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I used to sharpen them by hand a a Dremel like Leo Van Der Loo, but after a couple of sharpenings the teeth became uneven, so I made a simple automatic blade sharpener. https://lennartdelin.smugmug.com/Woodworking/Workshop/Blade-sharpener/i-QGHq7HK

A lot like the industrial band sharpener but only touching the top tip of the tooth rather than grinding the whole tooth, very simple device Lennard, though I find that my bands get fatigue after maybe 2 sharpening and it is time for a new band, also my saw has a much shorter band and coarse 3 TPI making for a lot les teeth to sharpen :))
 

Emiliano Achaval

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Reed. Jointing the teeth is a hand saw sharpening term. You run a file or stone over the top of the teeth leveling them so they all.cut at the same time. After that you file each tooth until its sharp.
I had the same question, thank you John. So, overall, was worth it right, in a pinch?
 
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Lennart ......That is totally cool. What an idea and what a neat tool.

What I have found is that about the time my band saw blade gets really dull, it is just time to put on a new blade.
I have sharpened them using a Dremel tool and it works........but I find that the weld on the blade is getting weak about the same time the blade becomes dull. About three cuts after I have spent 15 minutes sharpening the blade.....the blade breaks. So, I always try and keep a new one hanging on the wall to just replace the dull one.
First I think you should sharpen a blade or gouge or whatever when it is not longer sharp and not wait until it is dull. Second, if the blade breaks I suggest you get a better quality blade. In the last 40 years I think one blade broke due to a poor weld.
 
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John, That’s seems like a lot of effort for a a blade that won’t be as good as new after sharpening. I tried manually sharpening but the results were never that good. I’d rather spend a few minutes brazing a new blade for less than $8 using reel stock purchased on eBay. Always thought of you as an industrious type so I’m a bit surprised that you aren’t already doing this. Wonder if your big bandsaw would stress a brazed joint too much since it would have higher tension?
 

Roger Wiegand

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Anyone know of a commercial sharpening service? Specifically for carbide resaw blades. They cost about $350 so would seem to be well worth re-sharpening. Seems like there's plenty of carbide there. I called my local shops and they don't do it and couldn't (or wouldn't) refer me to anyone) I'm leery of messing it up doing it freehand with a dremel.
 
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I had one of the Lennox carbide tipped blades. The saw shop where I had my blades resharpened wouldn't touch it because the tips were so small, it was impossible. So, I guess it depends on your blade. If you bought it locally, you may be able to get it done there. My saw shop told me when I first started getting blades there that the carbide tipped blades were for sawing veneers. I tried one out anyway for my bowl blanks. Yup, they were right...

robo hippy
 
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