Sharpening bandsaw blades

[Derek Cohen]

I was asked to explain how I go about sharpening my bandsaw blades, and finally got around to putting together a couple of photos.


Let me say first that I did not invent this method. It is widely used. I learned it on YouTube, that font of all important wisdom


The fixture is new, and really thrown together in about 20 minutes. Before this, for a number of years, I would simply freehand this process. That worked well. Eventually .. recently .. I decided a fixture would offer more reliable results and less hand fatigue. Well, I think that this is so.


The main tool is a Dremel with a small diamond disk (the disks are available for pennies on eBay).


The blade here is bimetal 3 tpi 10mm wide. These are easy to sharpen. I use these blades for most everything except re-sawing wide boards.


I have also very successfully sharpened a 1.3 tpi 1" Lenox Woodmaster CT, which is a carbide tipped resaw blade.


The set up ...





This is made of two pieces of ply, at 90 degrees, the Dremel is wedged between the brackets at the desired angle, and held on with velcro straps ..





The method ...


Simply "touch" the back of the tooth and grind a teensy weensy flat. Damn these technical terms - not too complex I hope? The angle I choose is in line with the back, but it is not critical. What I believe that the fixture does (better than freehanding) is keep the height of the teeth the same. That ensures that all teeth are cutting.




Step 1. Mark the start of the blade (blue tape).


Step 2. Set the fixture against the bandsaw fence to keep it tracking square.


Step 3. Simply push the wheel into the tooth.


Below you can see (not too well, I'm afraid - the shiny spot looks the length of the tooth, which it is not) a tiny silver shine on the back of the teeth sharpened, and the absence of this on those unsharpened ... a better picture would resemble the sharpening of a backsaw ..





The result ...


The wood here is hard, dry Jarrah. The two sides are the result of cutting with a freshly sharpened blade.





Regards from Perth


Derek

[Doug Garson]

Looks good, not sure the jig as is would keep the height of all teeth the same, it would keep the angle consistent and put less stress on your hand. If you added a stop, it would keep all the teeth the same height. I've just sharpened my bandsaw blade once, might follow your example next time. Thanks for sharing.

[Derek Cohen]

Good suggestion, Doug. Easy enough to add a stop to the fixture.

Regards from Perth

Derek

[Melvin Feng]

Thanks for posting your setup!

Right now the blade I primarily use is the 1.25" Laguna Resaw King, and I've just been sending it out to them to get sharpened. I think the blade is expensive enough that this still makes sense. The sharpening would also need to be different, as I believe they sharpen the face of the carbide tooth, not the back.

For my other blades though, this setup could make sense for sure. I have a mix of timberwolf blades and lenox dimaster 2 bimetal blades, but I don't use them all that often, so they last a long time (I primarily keep the resaw king on the bandsaw). When these blades are dull, I'll keep this thread bookmarked for ideas on sharpening.

What I had originally thought about was cutting a block of wood to hold a diamond credit card sharpener at the correct angle for the tooth of the particular blade I was using, and then sharpening the 'front' of the tooth. I think it would only need a couple swipes per tooth. What are your thoughts on something like that?

[John TenEyck]

Thanks very much Derek. I think I'll try it, with the addition of a stop to better assure all teeth are sharpened equally.

As for sharpening the face or the back of the tooth I don't think it makes a huge difference; the most important thing is the tip of the tooth. Technically, yes, sharpening the face would be best, but from a practical standpoint it's probably not a big deal. Maybe the cut quality won't be quite as good?

John

[Derek Cohen]

Melvin and John, I have been thinking about matters such as indexing (which was a query raised on another forum) and sharpening the face vs back.

I do not index - this method is as basic as it can be without doing it freehand. It is better than freehand, as the angle is consistent.

How long can it be done? I have used the freehand method for several years, and sharpened the 10mm bimetal blades about 5 times. Then I toss them. I would say that I have had my monies worth. The cut can get slightly smoother each time since there is fractionally less set with each sharpening.

What limits how long you can re-sharpen is, firstly, the size of the gullet - too small and it cannot carry away sawdust, and then it loads up and affects tracking. The second factor is the stiffness of the blade. Carbide blades are stiffer as they are thicker. They eventually fracture, and this is more common among bandsaws with smaller wheels, such as 14” (more bending). My Hammer has a roughly 18” wheel, and my last 1” Lenox Woodmaster CT, a carbide re-saw blade, disintegrated. It had been sharpened about 5 times.

Back vs front? Not much difference - both leave the bevel edge sharp by removing the wear bevel.

Here is a method for sharpening the front. But there is some risk that one may alter the cutting angle by sharpening the front if you do this freehand ...

https://m.youtube.com/watch?lc=z12rv...&v=vKnlQ6ANNO0

The number of teeth come into the equation. Too many and it will take hours. The 10mm 3tpi bimetal blades take about 20-30 minutes. The 1.3 tpi 1” blades take about 10-15 minutes.

I leave the blade on the bandsaw - some like to do this task freehand on a bench grinder, and remove the blade to do so. Leaving the blade on the bandsaw makes it easier to keep the angle consistent ... and yet the bench grinder method still works well, which says that the sharpening is quite accomodating to angles. I do release some of the tension from the bandsaw, and work with the blade moving down. This is less tiring.

Regards from Perth

Derek

[Melvin Feng]

That's a good reminder about the grinder, I had forgotten about that method. I think that would be fairly easy with the 1" timberwolf blade I have, but I'm not sure about the lenox dimaster 2 blades that I have, I have 1/4, 3/8, and 1/2. When I need to sharpen one of them, I'll see if I can get the angle right to be able to sharpen an individual tooth on the more narrow blades with a higher TPI on the grinder with the CBN wheel - I have the mega squares, so I can use the side of the wheel as long as I can maneuver the blade around the rest of the grinder.

[Myles Moran]

Is your jig sharpening all the teeth in the setup you show, or are you flipping it for half of the teeth? I guess to put it in tablesaw blade descriptions I get, is it a FTG grind or an ATB?

[Bruce King]

Anyone did it this way?

[Mark Gibney]

Good old Dremel tool. Seems every household has one, every shop, but it is a support tool, and flies under the radar. I always feel a bit like a dentist when I use it.
Thanks for posting the sharpening method, I will use it.

[Derek Cohen]

Is your jig sharpening all the teeth in the setup you show, or are you flipping it for half of the teeth? I guess to put it in tablesaw blade descriptions I get, is it a FTG grind or an ATB?

I grind/sharpen every tooth.

Regards from Perth

Derek

[John K Jordan]

Looks good, not sure the jig as is would keep the height of all teeth the same, it would keep the angle consistent and put less stress on your hand. If you added a stop, it would keep all the teeth the same height. I've just sharpened my bandsaw blade once, might follow your example next time. Thanks for sharing.

If adding a stop and sharpening on the bandsaw, it might also be helpful to constrain the blade from moving away from the grinder - some smaller blades may be flexible. Perhaps either temporarily adjust the thrust bearings to touch the blade or add something rigid to the jig or table, perhaps with a slot for the blade to reduce chatter if using a relatively coarse wheel on a flexible blade.

However, I do wonder about the value of a horizontal stop without a way to index the teeth - for the angled cutter to grind away a consistent amount would rely on vertically positioning each tooth consistently.

If I built an indexer, it might look like the one on my chainsaw sharpening machine, but in reverse - move the blade up to move a spring loaded contact over the tooth then move it down a tad to secure it in the gullet. Or maybe an indexing device could be added to the leading edge of the jig.

BTW, I don't have much trouble keeping the angle consistent when sharpening by hand. I rest my hand on the table and hold the Dremel such that angle can't change much. I watch the shiny spot on the first few teeth to get the angle I want. I've been sharpening this way for over a decade. For me, the key to sharpening by hand with consistency and without strain on hand/arm, back, and neck is a comfortable stool at the right height for my bandsaw table. Good lighting helps too.

One thing I may have mentioned in another thread on this topic - it may be difficult to tell when a blade is getting dull. If I run my finger up over the teeth even a dull blade feels sharp. However, if I slide my fingernail upwards over the teeth the degree of sharpness is immediately obvious. Sort of like testing a knife edge with the fingernail.

Years ago well-known professional woodturner and writer Steven Russell wrote an excellent article on sharpening bandsaw blades, one of the many classical gems of his experience on his web site. I don't know when I wrote it but I see it has a 2006 copyright. Sadly, Stephen quit updating and removed the site years ago but fortunately still available on the wayback machine, the internet archive:
https://web.archive.org/web/20170930...aw-blades.html

JKJ