How do you sharpen your saw's spine?

[Nix]

As you guys already know...one of the great things about the saw blade is its sharp spine. The spine makes a great little scraper and fire steel (ferrocerium rod) striker. I use mine to scrape off those annoying stickers that seem to come on everything. The 90º spine is usually pretty sharp, with a fine burr on it. This makes it work a bit like a bench scraper. (albeit one with some sharp teeth sticking out of the top....)

However, like awl things that get used, the spine needs to be resharpened. Preferably back to a perfect 90º. I'm curious to know how you guys sharpen the spine of your SAK saws....without damaging the teeth of the saw itself, or your hand, for that matter.

I think I need to up my game here. Right now I just freehand the spine with a mill file and then hone it with a smooth steel designed to roll the burr over. (Same way I do for a bench scraper.) Sometimes I become more ambitious and use a diamond plate. But, I think I could do better and I'm looking for more reliable methods. I have a few ideas, but am interested in what other SAK knights have found helpful.

Please share your saw sharpening technique! 

[MacGyver]

As you guys already know...one of the great things about the saw blade is its sharp spine. The spine makes a great little scraper and fire steel (ferrocerium rod) striker. I use mine to scrape off those annoying stickers that seem to come on everything. The 90º spine is usually pretty sharp, with a fine burr on it. This makes it work a bit like a bench scraper. (albeit one with some sharp teeth sticking out of the top....)

However, like awl things that get used, the spine needs to be resharpened. Preferably back to a perfect 90º. I'm curious to know how you guys sharpen the spine of your SAK saws....without damaging the teeth of the saw itself, or your hand, for that matter.

I think I need to up my game here. Right now I just freehand the spine with a mill file and then hone it with a smooth steel designed to roll the burr over. (Same way I do for a bench scraper.) Sometimes I become more ambitious and use a diamond plate. But, I think I could do better and I'm looking for more reliable methods. I have a few ideas, but am interested in what other SAK knights have found helpful.

Please share your saw sharpening technique!

I never sharpened any of mine...

But, as always, Felix Immler always has great tips 

[Nix]

Nice video!

I've tried my bench vise....with the jaws protected with a bit of leather. This protects the saw teeth as well. The saw teeth are (the kerf is) a bit wider than the spine, which is great for sawing. But that does mean one has to be careful when clamping in a vise.

I don't have a bench grinder, but that seems a tad aggressive and could generate some real heat. I suppose a Dremmel with a drum stone/sander could be mounted in a table at 90º. That might provide a bit of a guide to keep the stone at 90º. Interesting idea, but, again, be careful about generating too much heat or removing too much material.

Good to see Felix demonstrating the utility of the saw's spine as a scraper. I'm going to have to try peeling a carrot or some ginger with a saw spine now!   

[Marcellus]

On a flat surface.  No angle.

Hard sharpening stone.

Wet/dry sandpaper taped to a sheet of glass maybe.

Make sense? 

[enki_ck]

I'd put it in a vice as Nix said, with some padding to protect the teeth, and give the spine a few passes with a wide, fine diamond stone. Should restore the angle just fine without removing too much metal and maintaining the angle. Too much can go wrong on an angle grinder and even more so with a dremel, hard to maintain an angle while pressing it to something that spins so fast and with that much force, and with a dremel, you might end up with lots of different angles on your SAK spine.

[Nix]

 

[Nix]

On a flat surface.  No angle.

Hard sharpening stone.

Wet/dry sandpaper taped to a sheet of glass maybe.

Make sense?

I have a flat....very flat....diamond plate. The challenge is to keep the spine at 90º. Especially when the spine is not 90º to the flat of the blade....because of the wider kerf. But I do have a couple ideas.......


Add: Marcellus, have you sharpened your SAK saws?      I'm not trying to overcomplicate this, and I have had reasonably good results just doing it freehand. But, as with every edge, it's be nice to do the best job possible.

[MacGyver]

Just a very little side track on the OT, but since it's saw related...

This one is great to those that say that "what branch you can cut with the Vic saw you can also break with your hands..."



Let's see them break that one... 

[Marcellus]

Nix
I noticed  Felix files or lightly grinds the back only.
He leaves a burr so he can use the spine more efficiently for all his woodcraft processes.
His method is simple , but looks like you don't  try it with your favorite knife with a grinder the  first time!

I would be very careful with a grinder or dremel ,as one slip could render the saw blade really buggered up.
The file method is a lot safer. More control.

I have used a flat Arkansas stone to  shape  the sides and spine.  Followed by wet/dry sandpaper taped to a wood block.
I check my spine  with a magnifier to see that the 90 degree angle is  maintained.
It works,  but unless saw is damaged,  prefer not to bother.

Going forward I am just going to use the Felix method with a file.
His method is a modification of the factory file with the burrs left on the top of the sides.
The burr can be detected with your finger nail.
My four saw blades from factory are smooth sided so this is a mod of sorts.

Maybe you don't want to modify all your saws into Felix Imler specials? 
Just smooth out the burr created by filing spine.

Marcellus

[Nix]

Maybe you don't want to modify all your saws into Felix Imler specials? 
Just smooth out the burr created by filing spine.

Marcellus

Not at awl... I want that burr!   

The burr is essential for a scraper (in this case saw spine). It's the burr that does the cutting. That's why I used a honing rod after sharpening: to curl the burr over and harden it. As a scraper is used, the burr can become folded back. Often just honing a burr with a slick metal rod or piece of glass can roll the burr back to 90º or better and get the scraper working again. The first step for me when a saw spine (or bench scraper) seems less than aggressive in cutting (while scraping) is to hone the spine with a rod or smooth piece or round glass.

Here is my honing rod and a plain steel rod that seems to work fairly well, too:




Felix doesn't do this final step, but I highly recommend it. 

[Marcellus]

Not at awl... I want that burr!   

The burr is essential for a scraper (in this case saw spine). It's the burr that does the cutting. That's why I used a honing rod after sharpening: to curl the burr over and harden it. As a scraper is used, the burr can become folded back. Often just honing a burr with a slick metal rod or piece of glass can roll the burr back to 90º or better and get the scraper working again. The first step for me when a saw spine (or bench scraper) seems less than aggressive in cutting (while scraping) is to hone the spine with a rod or smooth piece or round glass.

Here is my honing rod and a plain steel rod that seems to work fairly well, too:

(Image removed from quote.)


OK,  seems like you're  all set.

I wasn't  sure all what you wanted your saw to do.

I suspect hand sharpening the saw  spine  with a diamond file  would work well for you.

[Nix]

I suspect hand sharpening the saw  spine  with a diamond file  would work well for you.

Thanks. I'm thinking about way to make a jig. Or to use my vise in a jig-like manner.

I feel pretty confident freehand sharpening a knife edge, but I have found that it can be a bit trickier to precisely sharpen a saw spine or bench scraper to 90º...with a decent burr.

On a knife edge, I don't want a burr....right?  Just a clean cutting edge.

But...as you and Felix note....the burr on the spine is a real asset.

[Marcellus]

Thanks. I'm thinking about way to make a jig. Or to use my vise in a jig-like manner.

I feel pretty confident freehand sharpening a knife edge, but I have found that it can be a bit trickier to precisely sharpen a saw spine or bench scraper to 90º...with a decent burr.

On a knife edge, I don't want a burr....right?  Just a clean cutting edge.

But...as you and Felix note....the burr on the spine is a real asset.

Right,  no burr on the edge.  Burr = dull edge.

Just did the Felix method.
Simply put saw blade in a vise ( padded Jaws)
Checked spine with a level.
Used a small metal file to square off spine.
Raised burr on each side while neatly squaring spine.
Done
Easy peasey.


Happy Holidays

[Nix]

Nice!

[sir_mike]

I have touched mine saw spine up but laying a bench stone down, then like Felix did, wrapped the blade some so it can't bend/close on you.  Then I lay the spine on the stone and just go back and forth, keeping the 90 degree with one hand on the sak handle and one on the saw blade wearing a leather glove to protect from the saw teeth.  :Go back and forth slowly and it works fine.

I have also put my Spyderco triangles in their holder so they lay flat and done the same thing!

This may not work or take a long time if the spine has alot of use on it where it needs alot of attention but for quick touchups it works.

[cody6268]

Am I nuts by saying most of mine will strike a fire steel just fine as-is?

[Nix]

Nope. Most come from the Vic factory with a good 90º spine.   

[Don Pablo]

I've seen knock-off SAKs with polished saws that have round spines and round teeth.