Thread: Sharpening bandsaw blades

That angle seems to shallow to me. I'd be making it almost back to the original angle.

The teeth on that blade appear to have a bit of "glint" on them - if so that would indicate you are going to need to remove a lot of tooth tip to recover a sharp top. A close of the teeth might be useful.

I cant see the logic of removing more metal from the back of the tooth, but if it doesn't work I'll change it.

The glint is probably the TCT which are tiny on these blades.

Originally Posted by pommyphil

I cant see the logic of removing more metal from the back of the tooth, but if it doesn't work I'll change it.

The glint is probably the TCT which are tiny on these blades.

I've sharpened several dozen BS blades using the bandsaw sharpener at the milling yard so while I wouldn't call myself a pro sharpener. However, I have experimented enough to determine that significantly lowering the tip angle will reduce the max penetration of the teeth so it cuts slower - but probably not as slowly as a blunt blade .

Unless the teeth are significantly rounded over very little metal should need to be removed to remake the tips at close to their original angle. However, once the tip angle is reduced significantly much more metal will need to be removed reestablish the tip angle so starting resharpening with an angle closer to the original would seem to make sense.

Still like to see close up photos of the tips.

Originally Posted by pommyphil

IMG_20210309_170749015.jpg

The other component of the jig that I suggest you add is an adjustable stop. Like a piece of wood clamped to the table to limit the forward travel of the slide so that all the teeth are ground to the same height. Perhaps something like that may have been part of your design, but yet to be implemented, Phil.

Measure (I use Verniers) to find the lowest height tooth (excluding any badly damaged teeth, as in chipped) and set the forward travel (lightly tap stop with hammer for fine adjustments) to restore that tooth to a full cutting face right out to the tip and then grind all of the other teeth to match so that they are all working equally in doing the cutting.

I find an inspection loupe, separate small LED torch and a mirror (to look up under the tooth) are invaluable to see progress towards a fresh cutting edge.

Carbide teeth are not prone to forming wire edges when ground. But standard teeth and bi-metal are. I have reground standard teeth with this method and you can get some more life out of them if only very small amounts of tooth are removed. With those I run some softwood scrap through the freshly reground blade to remove any wire edges before using on a job. They can be grabby before any wire edges have been removed.

If you resharpen regularly you only need to grind off a very small amount each time.

I know I'm telling most of you how to suck eggs here, but there may be some new hands who might benefit from some of the above.

And, it's almost time for me to head over to the Men's Shed now to sharpen some more blades, which is about all I seem to do there nowadays. They are pretty hard on anything that cuts...

Yes Neil I thought about a stop but assumed that would entail a spring loaded Pawl to ensure that each tooth was held at the same height.
I thought that by just eyeballing the height I'd avoid wearing a groove in the diamond wheel. But not hard to add a stop and pawl if required. Thanks.

There's no need for a complicated stop/pawl, really. And if the blade 'wanders' back 'n forth on the wheel (many do while still producing an acceptable cut) then there's no guarantee that you will actually be getting a constant tooth height, especially if measuring from the back of the blade.

It's a simple matter to mount a bracket on the slide with a 'finger' that contacts the bottom of an appropriate gullet.

For many years I used a jig that had a dowel (actually, I vaguely remember using a broken drill bit there) set across in front of - and slightly below - the grinding wheel. In use I'd push the slide forward until the wheel was almost cutting then move the blade down slightly so the tooth below the one to be reground 'hooked over' the dowel.

Grind, slide back while lifting the BS blade slightly, rinse, repeat.

Pros:
A) it makes sharpening easily consistent. (ie. Little thought is required once set up. )
B) it's part of the jig, so no fiddly extra parts that need to be stored/found when comes the time.

Cons:
A) it can be damned frustrating getting the Dremel mounted in just the right spot in the jig for the first cut.
B) if the Dremel moves even the slightest bit in it's mount, all bets are off. But that's true for ANY sort of jig, yeah?

Originally Posted by Skew ChiDAMN!!

It's a simple matter to mount a bracket on the slide with a 'finger' that contacts the bottom of an appropriate gullet.

For many years I used a jig that had a dowel (actually, I vaguely remember using a broken drill bit there) set across in front of - and slightly below - the grinding wheel. In use I'd push the slide forward until the wheel was almost cutting then move the blade down slightly so the tooth below the one to be reground 'hooked over' the dowel.

Grind, slide back while lifting the BS blade slightly, rinse, repeat.

Yes, I have done the height positioning in a very similar way to Andy.

I just used an appropriately sized rod to match the gullet size. Initially I made a separate cradle for the rod to sit in with a slot for the blade to pass through, etc., etc., but eventually just let the rod roll backward and forward with a couple of brads to stop it rolling too far away. The rod finds its own correct position in the gullet when I pulled down on the upper wheel with my left hand while the right hand moves the Dremel forward then back. The rod is nudged forward by the back of the next tooth as the blade is lifted to position it to grind that next tooth.

You do need clean gullets to use this method if you want accuracy. I use Citristrip (let it sit on there for a bit) and then a wire brush to remove the glazed on sap/crud, but best done with the blade off the BS, especially if you are precious about the paint job on your BS. And, of course, avoid getting it in your eyes. I don't know what the Citristrip will do your wheel tyres if any of that is left on the blade, so I always scrub it off in warm water before putting back on the BS. There may be better options that Citristrip, but that is what I use and it does a good job, IME.

Andy may have the right touch to get a reasonably even lot of teeth, but I'm hopeless at freehand and need any help I can get to have any chance of success.

I bought one of the following units for our local Men's Shed to try to keep their circular saw blades from being constantly blunt. There seems to be no shortage of diamonds in the wheels used on these units.

Circular Saw Blade Sharpener | Power Tools and Machines

I've been thinking about how to set it up to also sharpen BS blades. Has anyone seen a design for using one of these to do that?

I'll start up a separate thread (so as not to hijack this one) if anyone has seen anything that might point me in the right direction with that. Please don't reply here, but PM and I'll get that separate thread going for this topic.

BTW, the pawl on this and similar level units is totally inadequate to the task, which is a shame given the otherwise substantial build on these units. That problem would also be a drawback if adapting it to also sharpen bandsaws blades.

On the subject of the stop, I don't use one when sharpening. The jig I use has a flat base which I can slide around the table, but in practice I move it up so the wheel is close to the tooth, then hold the jig pretty still, I then flex the blade forward to contact the cutoff wheel to polish the back of the tooth (just the bit of the back in the tip area actually). I release the blade with my right hand to terminate the contact between the blade and the wheel. I then slide the jig away, reposition the blade for the next tooth, slide the jig up "close" then flex the blade and tooth forward to get contact again.

The results I get on a 3/8 4tpi and 1/2" 3tpi blades are at least as good as new, if and only if the blade has been properly cleaned before sharpening. I use a white vinegar bath to clean the blade, wipe clean next day, rinse with water, then spray with WD40. Of course there is nothing to stop you doing a quick touch up on the machine without cleaning, but the blade will not perform as well as one which you cleaned properly before sharpening (in my experience)

Originally Posted by NeilS

I bought one of the following units for our local Men's Shed to try to keep their circular saw blades from being constantly blunt. There seems to be no shortage of diamonds in the wheels used on these units.

Circular Saw Blade Sharpener | Power Tools and Machines

I've been thinking about how to set it up to also sharpen BS blades. Has anyone seen a design for using one of these to do that?

I'll start up a separate thread (so as not to hijack this one) if anyone has seen anything that might point me in the right direction with that. Please don't reply here, but PM and I'll get that separate thread going for this topic.

BTW, the pawl on this and similar level units is totally inadequate to the task, which is a shame given the otherwise substantial build on these units. That problem would also be a drawback if adapting it to also sharpen bandsaws blades.

Neil, here's one,Sharpen Your Bandsaw With Harbor Freight Tool - YouTube A bit basic and I think it needs something ( a roller? ) to hold the blade down.

This one How do we SHARPEN our Blades for our NORWOOD SAWMILL - YouTube is more complex but looks better. Good old Utube

Originally Posted by pommyphil

This one How do we SHARPEN our Blades for our NORWOOD SAWMILL - YouTube is more complex but looks better. Good old Utube

This is the one I use.


This is a 12V system so you can run it off a car battery and it uses an angle grinder size motor with a 4" diamond wheel
Note how it also tilts the grinding wheel from side to side to generate alternating angles on the teeth. It actually creates a "left - centre - right" pattern.

We bought 3 new blades for the mill but it also came with 10 used blades but they were all right - left - right pattern and the grinder/setter all work on the left - centre - right patter so I had to reset the teeth on 2/3 of the teeth - that was painful.
Fortunately the boss decided to buy an bandsaw setter which does up to 350 teeth per minute - athough we nominally operate it at around 120 teeth per minute.
Re-stetting the teeth was sone at about 60 teeth per minute and was not done in a single pass but required about 6 passes to get close to the desired pattern.
I've only converted 3 blades but have managed to not break any teeth.

Originally Posted by BobL

This is the one I use.

This is a 12V system so you can run it off a car battery and it uses an angle grinder size motor with a 4" diamond wheel
Note how it also tilts the grinding wheel from side to side to generate alternating angles on the teeth. It actually creates a "left - centre - right" pattern.

We bought 3 new blades for the mill but it also came with 10 used blades but they were all right - left - right pattern and the grinder/setter all work on the left - centre - right patter so I had to reset the teeth on 2/3 of the teeth - that was painful.
Fortunately the boss decided to buy an bandsaw setter which does up to 350 teeth per minute - although we nominally operate it at around 120 teeth per minute.
Re-stetting the teeth was some at about 60 teeth per minute and was not done in a single pass but required about 6 passes to get close to the desired pattern.
I've only converted 3 blades but have managed to not break any teeth.

Thanks Bob.

That one sure looks like the bees knees and I expect invaluable if you are running a slabbing mill.

From what I can see, all of the premium sharpeners are re-grinding the whole tooth, including the gullet profile, which is going to be important if you are re-sharpening many times. And that would have the added advantage of removing any micro-cracking in the gullets where they say failure starts (besides faulty weld joins, which I've had happen).

A cam seems to be at the heart of the mechanism, which would mean different cams matched to each tooth pitch size. Adapting our current CS blade sharpener to do this is not looking like a Men's Shed project, well not for he crew at my local Shed!

Originally Posted by pommyphil

Neil, here's one,Sharpen Your Bandsaw With Harbor Freight Tool - YouTube A bit basic and I think it needs something ( a roller? ) to hold the blade down.

This one How do we SHARPEN our Blades for our NORWOOD SAWMILL - YouTube is more complex but looks better. Good old Utube

Thanks, Phil.

I started with that first one and it was so flimsy, hard to setup, and inconsistent that it was quickly replaced with the second one I posted.

Your second link looks like a good unit, but I am staring to realise that the cams used in these are matched to particular blade pitch sizes, which becomes an issue if you are having to do many different blade sizes. Oh well, back to the drawing board!

Originally Posted by NeilS

Thanks Bob.

That one sure looks like the bees knees and I expect invaluable if you are running a slabbing mill.

From what I can see, all of the premium sharpeners are re-grinding the whole tooth, including the gullet profile, which is going to be important if you are re-sharpening many times. And that would have the added advantage of removing any micro-cracking in the gullets where they say failure starts (besides faulty weld joins, which I've had happen).

The Dinasaw setter and the sharpener use the same cam mechanism. The stock setter is limited to a max of 1 TPI and several of our blades are 0.75 TPI so I took the cam mechanism apart and machined and repositioned a couple of parts and made a new pawl stop so that the pawl could reach further to be able to grab the next tooth. They are relatively intricate but would not be beyond a good machinist. I wish I had taken some photos while I had it apart.

There are bewildering range of sharpening profile possibilities, deeper/shallower gullets, angles of both the front and back of the teeth, the extent of the left and right offset angles. I managed to get the left/right angles mismatched and unbeknownst to me that often produced a diving cut which I blamed on every thing but and was chasing my tall for more than a month. I even built a fancy blade flattening machine because I thought a "cup" was developing across the blade. It turns out there was a small cup but it was smaller than the kerf.

It's also real easy to not adjust things quite right and then something slips and just when you are not watching it ends up cutting a tooth or even two off. I have managed to cut several - fortunately it was on the practice blade which is what I learned on.

Talking about sharpening I need to go down to the milling yard and sharpen some blades If I get some time I might take the cover off the sharpener and take some pics of teh cams.