Sharpening bandsaw blades in the shop

[John K Jordan]

I'm sure this has been discussed before, but those who don't know might be interested.

Since bandsaw blades are expensive, I usually sharpen them once or twice to extend the life. I use a Dremel with a thin metal-cutting disk and sharpen while the blade is on the saw. I've been using this method for many years.

I don't worry about sharpening the "normal" way by grinding the gullets - that would be a lot harder to do by hand and take way too long anyway (my 18" saw has over 400 teeth on a 3tpi blade). I simply touch the flat of the disk briefly to the front of each tooth, angled to match the shape at the tip. Move the blade by hand to the next tooth and repeat.

bandsaw_sharpen.jpg

I touch for only a fraction of a second which is enough, less than 1/4 second for each tooth. It is important to not overheat and "blue" the tip since most blades have hardened teeth and heat would destroy that.

The last few days I've been cutting a lot of 10"-12" green sugar maple (hard maple) log sections into spindle turning blanks. I use 1/2" Lenox 3 tpi blades, my favorite blade for turning wood processing, green or dry. Sharpening as described above made the blade cut like new again. In fact, I almost think it felt sharper than new.

If you haven't tried sharpening your own blades and want to save some money, or simply need a sharp blade on a weekend evening when your last blade is dull, you might try this. It does take a bit of time for a long blade but if you already have a Dremel and the little abrasive cutting disk, it's like getting a blade for free.

JKJ

[Ira Matheny]

I, too, sharpen most of my bandsaw blades. I created a special angled 'stand' to which I attached the Dremel. I advance the blade, move the Dremel forward to hit the blade for less than a second, back off the dremel, re-index the blade, and repeat this process. I currently only sharpen my 7/8 inch pitch rough sawing blades.

After sharpening in this manner just a couple of times, I found my results were excellent.
The blade on my 36" Yates has been re-sharpened 5 or 6 time. It is cutting fast and accurate.

The 250" blade with 285 teeth takes only about 11 or 12 minutes to resharpen, but $75 to replace!

[Brice Rogers]

Thanks for the suggestion, John.

I need to buy some better blades first. I recently retired a fairly new 3 TPI blade. It still cut green wood very quickly. But the blade had lost virtually all of its set, making it impossible to cut any rounds with less than about a 30 inch radius. I think that it lost its set after about 10 feet of cutting.

What blade manufacturers do you recommend?

[Bob Bouis]

Sometimes it helps to refresh the gullets too. You can do it with a chainsaw file attachment for a dremel -- depending on the tooth size, of course. It doesn't really have to be the perfect diameter, either, just as long as it gets the tips and doesn't roll up.

It doesn't seem to take much in terms of accuracy to get a decent cut (for roughing, anyway).

[Reed Gray]

If I was going to do it myself, I would like to find a small CBN file of some sort and use lapping fluid. I am not sure if the little file for chainsaws will fit into the gullet of the 3 tpi blades. There may be diamond ones available. No idea what the saw shops use. Both sides of the tooth, the gullet and top, need to be touched up.

For blades, I prefer the Lennox Bimetal Diemaster blades. They are a bit more expensive, but they cut straighter and longer than any other blade out there. They resharpen very well.

robo hippy

[John K Jordan]

... I would like to find a small CBN file of some sort and use lapping fluid. ...

Speaking of CBN, have you seen that Rizza is selling CBN honing plates? Both sides, you can specify the grit, nice and big: 2-3/4x8". I got a couple to try, 320-1200. They work well, but I don't know if there is any advantage to using CBN over diamond on a hand-held hone since there is not a lot of heat involved.


JKJ

[allen thunem]

ok I'll bite, who or what is Rizza

[John K Jordan]

ok I'll bite, who or what is Rizza

Oh, sorry.

Ken Rizza of Woodturners Wonders sells CBN wheels, lights, sanding supplies, etc.

http://woodturnerswonders.com/

JKJ

[Dave Fritz]

I sharpen mine basically the same way only I do it off the saw while seated at a grinding wheel. Cut like new. I use blades from Ellis which is close to me so I can pick them up. They last a long time roughing out blanks and spindle stock.

[Craig Parks]

I wonder if anyone has ever tried to adapt a bench type chainsaw sharpener to sharpen bandsaw blades?

[Peter Blair]

I sharpen mine with a chain saw diamond hone on the inside of the gullet and after a few sharpenings I pull the blade and while sitting in the middle use a 'saw set' to re-set the blade. They do last a long long time this way.

[Mike Golka]

This is what I use
http://www.leevalley.com/en/Wood/pag...072,43086&ap=1

[Russell Neyman]

I've tried this with only moderate success. A buddy who prepares and sells bowl blanks professionally says the bandsaw blade problem most woodturners encounter goes beyond the sharpness going away. It's the kerf where things go awry. All the curves needed for bowl blanks knock the set away, which creates heat, and dulls the blade. So sharpen, but also fix the set of alternating teeth.

[John K Jordan]

I've tried this with only moderate success. A buddy who prepares and sells bowl blanks professionally says the bandsaw blade problem most woodturners encounter goes beyond the sharpness going away. It's the kerf where things go awry. All the curves needed for bowl blanks knock the set away, which creates heat, and dulls the blade. So sharpen, but also fix the set of alternating teeth.

As often is the case, the way we each use a tool makes a difference. In my case I only occasionally prepare bowl blanks. Much of my bandsaw use is with big pieces of green log sections I turn into spindle blanks, box blanks, etc. After drying, I use the bandsaw again to trim the sides and ends to see the figure and color and inspect for defects.

Since more of my cuts are straight than curved the kerf issue you mention has not been a problem. I suspect someone preparing bowl blanks for money is a more extreme user than some of us and would simply buy more blades rather than take the time to resharpen. Since I do not reset the teeth, I usually only sharpen 2-3 times since the grinding itself does gradually decrease the set. I think it helps to change the angle of the grinder to match the angle of each tooth. My 3-tpi Lenox blades are all Left-Right-Center.

I wonder if anyone makes a saw set tool for the large teeth found on a 3-4 tpi bandsaw blade. I have an old pistol-grip type made for handsaws but I think it's way too small to set big teeth.

BTW, it's not often mentioned but an old method to prepare a blade for curved cuts is to use an abrasive stone on the back of the blade while running to round the back corners and allow a tighter radius with less friction. I see Amazon even carries a stone made for this: https://www.amazon.com/Olson-AC70013.../dp/B003A07FNM

JKJ

[Bob Bouis]

$16 for a small stone on a stick? I know you're not endorsing the product, but a piece of scrap sandpaper and a wood block will do the same thing.

As far as set goes, one thing that seems to happen with a dull blade is that the blade drifts away from the fence and the wood pushes against the side of the blade like a wedge, forcing the teeth away from the fence. It sort of resembles a lack of set in that you feel like you're not getting a wide enough kerf, but the wandering is really caused by dullness.

Lately I have been using a 1tpi 1.25" band made for sawmills. I am not sure if it would be ideal for a saw with smaller wheels (mine are 24") or a slower blade speed, but it's easy to sharpen and very tough. I kinked something in it a while back, which stopped a 5hp motor dead in its tracks. I pulled it out and was amazed to find the blade ran perfectly straight afterwards. Also you have big teeth which can be sharpened many times, and a fat band so the set seems to hold up just fine. I think I've sharpened it five times since I put it on. I also don't see the need to cut blanks into perfect circles before mounting them on the lathe. Maybe if you're turning really precious, kiln-dried wood or something.

I did get the big saw fairly recently so take my observations with a grain of salt.