Sharpening Band Saw Blades

Discussion in 'Tutorials and Tips' started by Brian Hahn, Jun 14, 2006.

  1. Brian Hahn

    Brian Hahn

    Joined:
    May 30, 2005
    Messages:
    278
    Location:
    SW Wisconsin
    This is pretty long, but here's how I sharpen my band saw blades.

    I tried a lot of different methods before settling on my current method. I started with sharpening the blade on the saw with my old Craftsman 12-inch saw back in 1994. I've also tried touching the top of each tooth to a grinding wheel as described by Richard Raffan in his book Turned-Bowl Design. The problem that I had with grinding the top of each tooth, either on the saw or off, was getting a consistent amount of metal removal. Practice would have improved my results but...

    I sharpen my own hand saws and one thing I learned is that uniform teeth are essential to good saw performance. So hand sharpening the band saw blade was a logical step for me. I "lost" a few blades in the learning process, but what the heck, they were on the way to the trash can anyway.

    One thing that is very important is a consistent and light touch, especially when grinding the gullets. My current re-saw blade (in the pictures below) has been sharpened about 70 times and the teeth have been set three times. It still works "like new", but it's just about at the end of its useful life. I do have a new blade on the shelf, ready to step in when this one finally dies.

    First, I remove the blade from the band saw to sharpen it. Sharpening the blade on the saw is too awkward for me and it's too hard to get a consistent angle and amount of metal removal. I use a 10-inch wide traditional-style saw sharpening vise for my bench vise. I'll provide a description and some pictures in the next message. The wide vise lets me work on a lot of teeth before I have to shift the blade - a real time-saver. A couple of blocks of wood at the back of the bench support the other side of the blade to keep it from twisting and getting bent. (Picture 1)

    Basic sharpening:
    I put the blade in the vise with a little bit of the blade below the gullet exposed, maybe a 1/16". I start with the weld at the right end of the vise. The weld is an easy and convenient marker for when I've reached the end. I always sharpen the top of the teeth with a fine diamond hone, 3-5 light back and forth strokes, depending on how new the hone is and how dull the blade is. (Picture 2) The objective is to have the shiny area reach all the way to the tip of the tooth. Do the same number of strokes on each tooth. I like the EZE-Lap fine (red) hones because the entire surface is covered with diamond. They continue to work well even after the diamond abrasive has been knocked down. I probably get thirty or forty sharpenings from one hone.

    I originally tried to match the original angles on the teeth, but was prone to mess up occasionally. I eventually changed to sharpening all the teeth flat across - quicker, no mess-ups and the blade seemed to cut just as good if not better. Maybe there's a reason rip blades are sharpened straight across.

    I sharpen the gullets only if I'm cutting a soft and/or stringy wood - aspen, butternut, American elm, etc. The harder woods (cherry and above) don't seem to need it, but the soft woods clog the gullets and the debris doesn't clear if the gullet edges aren't sharp. I use a 5/32" chain saw stone in the Dremel to sharpen the gullets. Just one light back and forth stroke straight across the blade. (Picture 3) The real challenge here is to maintain a slight hook and not deepen it. Grinding too deep makes the blade too aggressive and it may pull itself forward into the wood. The gullets on the blade in the picture are ground a little too deep. It's OK in a soft wood like aspen, but it likes to grab in oak.

    I tried using a diamond burr for sharpening the gullets, but the diamond seemed to wear/break off rather quickly and then created big burrs on either side of the gullet -- not exactly the desired result. I tried using a chain saw file once - ended up with a very dull file. I haven't tried using a tungsten carbide cutter. I've got one, but it's not cheap and the chain saw stones seem to work just fine. (And they are a lot cheaper!)

    Finally, I brush the filings and sawdust off the blade with an old finger-nail brush "requisitioned" from the kitchen. (Background in Picture 3) Then I shift the blade to the right and do the next batch of teeth. (Since the teeth are facing left, rotating to the right minimizes the chance that the blade will snag something else on the bench.)

    It takes a little practice, but I can normally do a blade in about 11 minutes. Then I pop the blade back into the saw, set the tension and saw. I check the blade guides just to be sure, but since the saw was already set up for that exact blade, I save a couple of more minutes there.

    About every other time I twist the blade inside out to remove any angle biases I might be putting on the blade. It also lets me check on how square I'm holding the hone and Dremel tool.

    Setting the teeth:
    I'm still working on my technique for this. The big problem is the teeth are so hard that it is really easy to break them off. I didn't break any teeth the last two times, so maybe I've got a handle on it. I usually set the teeth when the kerf seems to be getting a little narrow - maybe every 20th time.

    I use a standard saw set that I probably bought it from Garrett-Wade twenty years ago. Putting too much set on the teeth will break them, especially on the expensive blades with the high alloy teeth. The 8 tpi setting on the saw set seems to be the largest set I can do without breaking teeth. I can do a larger set (kerf) with plain carbon-steel blades, but they don't last long enough to be worth the cost savings.

    I lay the blade on top of the table saw (only large clear surface in the shop) with a little hanging over the edge to work on and pull up a stool. I set all of the left (inside facing) teeth (every third tooth on my blades), then turn the blade inside out and set the right (now inside) teeth. Turn the blade back right-side out it's ready to be sharpened. Again, I find it convenient to work from the weld around to the weld.

    My Re-Saw Blade:
    I have a 14-inch Delta with riser blocks. For re-sawing I use a 5/8" - 3 tpi hook tooth blade (Olson from Woodcraft). I've tried other blades, but this is the one that works best for me. The blade has a three-tooth pattern, Left-Right-Center. The first thing I do is remove every other tooth using a mandrel-mounted grinding wheel (1" dia x 1/4" thick) on the Dremel. I start with the first tooth above the weld and work my way around the blade until I get back to the weld. If the blade has an odd number of teeth, the two-tooth gap spans the weld, which is convenient when I sharpen the blade. That makes it a 1.5 tpi blade with a L-C-R pattern. The blade cuts at least twice as fast because there is more room to clear the sawdust. It also seems to cut twice as long before it needs sharpening.

    Hope this is helpful -- Brian
     

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    Last edited: Sep 22, 2007
  2. Brian Hahn

    Brian Hahn

    Joined:
    May 30, 2005
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    278
    Location:
    SW Wisconsin
    Saw sharpening vise

    This vise is a standard design, loosely based on the one in Tage Frid's book Tage Frid Teaches Woodworking, Book I - Joinery. I probably saw design like mine somewhere, but I don't remember where or when.

    The jaws are two pieces of 10" x 4" x 3/4" oak. Any hardwood would work, I just happened to have the oak on hand. The outsides of the jaws are grooved to fit onto the bench vise jaws. The backs are also relieved for the pipe jaws in the vise. The rear pipe jaw is bigger than the front one, so I sized the relief in both jaws for the back so the vise is ambidextrous. The bottom of the jaws is also cut out for the vise's slide and the jaws actually rest on the slide, which keeps them from falling out when the vise is opened too far. The two jaws are joined at the bottom with two flat hinges. The pin side of the hinges is inside to act as a spacer between the jaws. This focuses the clamping force at the top of the jaws, providing a stronger grip on the blade. Finally, the tops of the jaws were beveled to make it easier to work close to the blade (and to avoid scraped knuckles).
     

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    Last edited: Sep 22, 2007
  3. Mr. Don

    Mr. Don

    Joined:
    Jan 31, 2006
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    255
    Location:
    Gaston, Oregon
    Saw sharpening

    Good info...but my time is best spent sawing, not sharpening. I use only Timberwolf blades in the 1" to 1 1/4"x 123" range on my Jet 16" bandsaw. I take the dull ones to my local Woodcraft store. They have a guy that comes by on a weekly basis and picks up all kinds of blades for sharpening. I can get 3 or 4 times out of a blade @ $8 a pop before the set is gone. The sharpened blades are better than when new, and I figure a week turn-around on the service. He does not even waste time on the "throw-aways" (use til dull, then toss 'em) like Olsen and the China and Japan imports. I order my blades direct from factory 10 at a time, and figure they cost about 1/4 to 1/3 of retail, and when I factor in the sharpening fees they are even more reasonable. Don't mean to rain on your parade....I am a high volume user, and gotta be cutting to be earning.
     
  4. Tom Lewis

    Tom Lewis

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    Jul 2, 2005
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    Location:
    Carlsbad NM
    Thanks Brian, very informative, I think I will give it a try.
     
  5. opa1047

    opa1047

    Joined:
    Jan 25, 2007
    Messages:
    4
    I sharpen mine on my Delta 8" grinder

    I use a 100 grit wheel on slow speed and just touch the back of each tooth. I've sharpened at least 20 times this way and they work better than new. I can sharpen my 1/2" 3tpi resaw blade and cut 1/8" veneers with no problem. I have a Jet 14" bandsaw with 1hp motor.
    It only takes about 5 minutes to do a 105" blade. I can tell the teeth are not the same height but I haven't noticed any adverse affect on my resawing so don't worry about it.
     
  6. Ron Sardo

    Ron Sardo Guest

    The gullet is really for chip extraction. No need to "sharpen" it.

    A deeper gullet will help clear the chips better
     
  7. gary webb

    gary webb

    Joined:
    Apr 2, 2007
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    Location:
    Peoria AZ
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    band saw blades

    the best way to sharpen band saw blades is go to sun belt ind web site and order a new one they make eny size and toth con for under 15 buckes don't be so tight it's only money
     

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