Thread: Bandsaw Blade Sharpening

Before looking into it today, I contemplated hand-filing (for a touch-up) ...

5.5m @ 20mm per tooth = 275 teeth - actually not as many as I'd imagined.

P1010322.jpg

There could be a small wedge-shaped chute to incline the file to a different angle.

But ... I really don't know yet what I would be aiming for.

- - - -
This thread mentions a Dremel (which you can find on Youtube) and mentions Leonard Lee's book (which I will look into) saying it is the back of the tooth that should be sharpened.
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https://www.woodworkforums.com/f27/ji...-blades-65171/

and another discussion: Old school bandsaw blade sharpening . . . - Woodworking Talk - Woodworkers Forum

talking about ...



Vs this modern machine adopting a different strategy ...



and the same thing simplified ...

This guy has his technique down ...




and another discussion thread: http://www.practicalmachinist.com/vb...arpener-94175/

More good ideas:

Originally Posted by pmcgee

- - - -
This thread mentions a Dremel (which you can find on Youtube) and mentions Leonard Lee's book (which I will look into) saying it is the back of the tooth that should be sharpened.
.
https://www.woodworkforums.com/f27/ji...-blades-65171/

I don't see how sharpening the back of the blade would work. It is the face and gullet that are important. The gullet is responsible for clearing the sawdust away which is why it also needs treatment.

Regards
Paul

Paul

What size bandsaw blades are we talking about? Like this one perhaps ?

You can find the full story at:

http://www.thisiscarpentry.com/2011/...-oaks-sawmill/

Regards
Paul

Originally Posted by Bushmiller

Paul
What size bandsaw blades are we talking about? Like this one perhaps ?Regards
Paul

Hah. I wish!

There is more to understand here obviously.

Obviously if you only sharpen the face of the tooth, or the back, then the tooth will become thinner and weaker.

At least one of the auto-sharpen videos shows the grind going down the face, along the gullet and over the back.
Then the wear becomes decreasing the total width of the band which makes sense.

But then again - machine sharpening of handsaws ... and chainsaws ... is seen as likely to remove too much material compared to hand sharpening. Maybe bandsaws are the same and a light touch on the front (or back) of the teeth might go a long way without too much wear.

Paul

Originally Posted by pmcgee

Hah. I wish!

There is more to understand here obviously.

Obviously if you only sharpen the face of the tooth, or the back, then the tooth will become thinner and weaker.

At least one of the auto-sharpen videos shows the grind going down the face, along the gullet and over the back.
Then the wear becomes decreasing the total width of the band which makes sense.

But then again - machine sharpening of handsaws ... and chainsaws ... is seen as likely to remove too much material compared to hand sharpening. Maybe bandsaws are the same and a light touch on the front (or back) of the teeth might go a long way without too much wear.

Paul

Just passing on my observations of Bandsaw Blades from chatting to the owner and observing at one of the local sawmills that I do a bit of work for occasionally.

He runs Woodmizer Mills and Resaws and uses 2 different Woodmiser grinders there, but mainly uses just one as he runs most blades at the some hook angle which from memory is 10° and for the tougher really hard stuff I think it's either 4° or 6°, can't remember. The diamond coated grind stones are made to suit the hook angle and grind the full face of the cutting edge. He also sets the teeth on the blades as well.

Anyway, in regards to decreasing the width of the blade due to grinding, it isn't a problem as either metal fatigue sets in before you lose too much width or teeth are so badly bent over from hitting hard or foreign objects that it requires too much work to grind back. Not to mention that the grinders don't remove a lot of metal, heck sometimes the blade has to run through 3 or 4 times to get the edge back if you've really blunted it.

Originally Posted by DJ's Timber

Anyway, in regards to decreasing the width of the blade due to grinding, it isn't a problem as either metal fatigue sets in before you lose too much width or teeth are so badly bent over from hitting hard or foreign objects that it requires too much work to grind back. Not to mention that the grinders don't remove a lot of metal, heck sometimes the blade has to run through 3 or 4 times to get the edge back if you've really blunted it.

Good points.

Blades vary a lot, needless to say, and often the hardened area of the tooth is quite small. It is quite easy to remove that after half a dozen sharpenings. Although at that point setting is required, it becomes academic as the blade is caput.

The barest amount only needs to be taken off the face of the tooth: Just enough to "freshen" the face and leave bright, shiny metal. In fact using a machine profiler I would suggest that less metal is removed than if you were shapening a hand saw with a file. A slightly more aggressive grind of the gullet would normally be employed, but in the case of a machine sharpener, the grinding wheel should lift off before it contacts the back of the tooth. If material is removed from the back of the tooth, the tooth becomes progressively weaker with each subsequent sharpening. All this takes quite a bit of setting up on a sharpening machine.

When I sharpen band blades I clean them first with steel wool, to remove sap and sawdust, and then spray them with WD40 or similar. This is to achieve consistent travel of the blade through the machine. Failure to do this will result in different amounts being taken off each tooth.

I have not tried this next suggestion but if I was looking at sharpening by hand I would try a dremel type tool with a suitably sized cylindrical grinding stone used at 90 deg to the blade. Possibly you could try this for two or three sharpenings and then go back to the professionals to correct any deviation that has occured.

It's clear that this task becomes more difficult as the number of teeth per inch increases.

Regards
Paul

I'm going to have a go at sharpening my bs blade ... so went looking for pictures of tooth profiles to see what I'm trying to achieve.

BTW Leonard Lee's book barely mentions bandsaws - three paragraphs.

I found this from the estimable wood-gears guy ...

Sharpening bandsaw blades

Still looking for the profiles.

Paul.

Two different approaches with a Dremel ... the first one has some discussion in the comments section on the Youtube page.

Only the second guy addresses the gullets.

Here's one for the enthusiast ... VariSharp CNC Band Saw Sharpener

Basic info here: Band Saw Blades 101 : eReplacementParts.com

Eg profiles ... bs woodmaster_ct.jpg Weldupclose.jpg


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Having searched around a bit, and then looked back at my blade, I see I have a positively raked hook tooth - and could probably stand to lose some rake in the sharpening process. So I'll try it and report back.

Incidentally - you can plug in numbers here and get prices: Woodmaster Wood Cutting Band Saw Blades - Custom Order Bandsaw Blades - BandSawBladesDirect.com

For me (5.5m - 1.3tpi - 1" wide) the options came out as -

Woodmaster C (carbon steel) $30

Woodmaster B (bi-metal) $96

Woodmaster CT (carbide tipped) $211

... I'd like to know if people see a benefit out of the B and CT options.

Cheers,
Paul

Originally Posted by pmcgee

- - -

For me (5.5m - 1.3tpi - 1" wide) the options came out as -

Woodmaster C (carbon steel) $30

Woodmaster B (bi-metal) $96

Woodmaster CT (carbide tipped) $211

... I'd like to know if people see a benefit out of the B and CT options.

Cheers,
Paul

Paul,
I have been running Woodmaster B, for a lot of years now, 1st blades I imported from the USA, now have them sent up from Henry Bros. I find they out perform carbon 10 to 1 from years of cutting, the only thing that slows them down is gravel/rocks or bolts in the wood. I spoke to Mark at Henry Bros, and for what I do, mainly wet and dry wood, he advised against TC. I have experimented sharpening my blades with an angle grinder(slowed down with a speed controller) fitted with a Flexovit wheel from a chainsaw sharpener in a modified drop saw frame. It was adjusted to cut down @ 7 deg+, and the only problem I have is getting the tooth advance uniform, to take the finest cut from the front of the tooth, but am still working on it. The freight down and back to have them resharpened is outrageous from up here, so I currently have 7 blunt blades
rgds,
Crocy

I agree with Crocy on the blades, but I have never been able to compare directly. I originally used carbon steel blades and when I returned to milling, in what I describe as my recreational milling era I went to bi-metal also on the recommendation of Mark at Henry Bros.

In my "professional" era I experimented with a tungsten blade. I was spending far too much time sharpening blades instead of cutting timber and this was the primary reason I added a swing saw to my mill.

The tungsten tipped blade was 2" wide as opposed to my normal 11/4" as that was all that was available at the time. It was also almost ten times the cost. I set it up on the machine with the teeth protruding beyond the wheel as per normal (my saw does not have a rubber band and relies on the teeth never contacting the wheel and in that regard is the same as that monster bandsaw I posted on this thread). being the safety conscious little devil I was I clamped the guard down tightly and made my first cut.

Unfortunately for me the clearances were now quite different and the blade contacted the guard cutting straight through the steel. You can see the cut on the left of the picture below. The blade, not surprisingly, had lost its edge.

I was devastated!

I then discovered the next shortcoming. How do you sharpen the blade. I tried those small hand held diamond sharpeners, but it was hopeless so I never was able to evaluate at all.

Regards
Paul

Originally Posted by Bushmiller

Unfortunately for me the clearances were now quite different and the blade contacted the guard cutting straight through the steel. You can see the cut on the left of the picture below. The blade, not surprisingly, had lost its edge.

Ay-chi-wow-ah!! That's gotta hurt!

"Not pleased" wouldn't even start to cover it. I'm glad my "learning experiences" have been on a smaller scale!

- -

I had a go at the sharpening this afternoon - and it was well worth a go.

I started with a 4" angle-grinder with a normal grinding wheel ... tried a couple of teeth and thought "that's a bit energetic"

I got out the Dick Smith dremel tool and used a little cylindrical pink stone for about twenty teeth or so.

I fell into a pattern of following the whole profile, from the back of one tooth, all along the gullet, and into the hook and out.

It was doing something, but I didn't feel it was making a great deal of an impression ... maybe a diamond burr might be different.

I went back to the angle-grinder (+ear muffs) and found I could touch up the blade firmly but lightly (!) - following the same pattern along the whole tooth.

I got into a bit of a rhythm, starting with the disc horizontal and tipping it up a little into the base of the hook and across under the point.

I found I needed to put a bit of wood between the guard and the upper wheel to apply some friction to stop the wheel rolling back when I moved to a new section. I could do about 20 teeth at a time.

The grinder is kinda heavy to hold - definitely took two hands. A few times when trying to start the pattern at the back of a tooth I wobbled and bomped into the point of the tooth ... which isn't the best idea ... so then needed to try to fix it up a bit.

It didn't remove very much material at all, and the result on trying the saw afterwards was a definite improvement. It remains to be seen how long it lasts, but I would certainly do it again. At the rate of material removal I could see it being sharpened many times, not just 2 or 3. And my band could stand to lose some of the set it has.

I was cutting up a lot of big stuff when I was last using the saw - in a bid to clean up the place - and I found the sheoak a lot slower cutting than the jarrah. I have a *big* lump of sheoak that has been sitting on the bandsaw table for six months waiting to be resawn, so it'll be very interesting to whack it through tomorrow and see how well it goes.

I am glad I have had the carbon-steel blade - it has been pretty forgiving to my learning process over the time I have had it and been through some big wood. it'll be interesting at some point to try a bi-metal blade and see how different it is.

Cheers,
Paul