How I Sharpen #6: Knives with Power Sharpener

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This is part 6 in a 6 part series: How I Sharpen

Haven't had a chance to get back to carving tools but I had a couple pocket knives that needed a refresh this weekend so I thought it would be worth throwing in here.  I hesitated because once again, I'll be using a powered sharpener.  But I have LOTS of knives and use stones on many of them so I'll do another entry for knives with diamonds or oil stones next time I get those out.

For this entry, I'll be using my Work Sharp Ken Onion Knife & Tool Sharpener with the Blade Grinder Attachment.  The tool itself is okay but adding the blade grinder attachment makes it awesome.  It's just a small belt grinder with adjustable guides to hold the knife at a consistent angle.  On the tool itself, I always found the guides hard to use and didn't get great results without spending a lot of time.  But when I attached the blade grinder, my results were MUCH quicker and more consistent.

Here she is:


One thing that makes it less than idiot-proof is how you maintain the angle.  You change the tilt of the belt then you lay the knife on the little platform on the left and use "muscle memory" to keep it flat as you lift it up and sharpen between the two top rollers. 

I found a design for a sliding support online and 3D printed it and decided to give it a try during this session.


But it was too flexible and didn't last long:


And honestly, it isn't necessary IMO.  I have no problem using the tool as intended and maintaining a consistent angle.  I just lay the knife on the platform,

Lock both wrists in the right position and lift it up and do a few passes.

Then I go back to the platform and reset my wrists and repeat.

The sharpener also has variable speed which is very nice.  You can control the speed with the trigger when holding it (like for mower blades) or when using it like this, you can lock the trigger engaged and there's a small rotary dial on the bottom of the trigger to adjust the speed.

So that's the tool.  These are the knives I am sharpening.

The black one is my EDC knife that goes everywhere with me assuming I don't have to fly...  It's a Benchmade 537 Bailout with a CPM-3V blade.  It's a tough one to sharpen on oil stones but diamonds work fine.  I have started using this Worksharp though because I like the "appleseed" edge it gives.  My EDC sees a lot of work and a lot of different materials so while I want it shaving-sharp when I sharpen, I also want some heavy durability from it and so far, this belt grinder is the best method I've found for obtaining both.  The red one is a Benchmade 535 Bugout with an S30V blade.  Also tough to hone on oilstones.  It's my backpack knife.  It could well be my EDC except I've fallen in love with the Tanto style blade on the Bailout.  And I don't like the red handle and black blade so much 😉  It's an excellent design though and I love the Axis Lock on both of these knives.  Makes one-handed opening and closing simple and it locks open with no slop whatsover.

The Bailout has been sharpened on this grinder previously.  But the Bugout I've always done with diamonds to keep flat bevels.  I've been so happy with the edge on the black one though, I decided to try it on the red one too.  So off we go.

Since I explained above how the sharpener works, I won't re-hash that part other than to point out a few things that hold true whether using stones or a powered sharpener.  First, is the shape of the Tanto blade.  After sharpening a few times, I noticed that I had rounded off the transition between the long edge and the tip.  So when I started using this powered sharpener on it, I reground it to gain the defined transition.  It's probably not a huge deal to a lot of people but I like to use that transition as a kind of tip for things like cutting paper with a straightedge or cutting packing tape open.  So I like a point there and not much of a radius.

You'll note in the last picture that I have dyed up the bevels on both knives.  This is a habit for me anytime I am grinding or sharpening something small.  My eyes ain't what they once were so I use the dye so I can see exactly how much I'm grinding where and make sure I'm holding the knife at the right angle.  These guys are a big help when sharpening too:

for seeing the condition of the edge on finer grit belts when you can't feel much of a burr.  I can look at the edge and see if I have a consistent edge along the full length before switching to the other side.

For the black knife, I sharpen the edge as though it's two distinct separate edges.  I start with the long one and I sharpen from the heel of the blade up to the transition point and stop there. 

Then I'll flip it and do the other side of the long edge.  Then once I've ground to a sharp point on the long edge, I'll do the short edge in the same manner.

The light makes it kinda hard to see but if you look at the point where the edges meet, you can clearly see a line which is where I stop my grinds on each edge.  You can also see in this pic how the taper grind on the blade from the spine to the edge makes the bevel wider on the tip than at the transition.  Another feature of the design I really like because it keeps me from breaking the tip when I'm using it to cut cable ties loose 😎

From here, I just switch belts and rinse and repeat.  For this knife since I am just resharpening with the existing bevels, I start at 1200 grit,  then 2500 and finally 12000 grit.

For the red knife, I'm making the bevel angle a little shallower so I started at 600 grit and progressed as above.  The procedure is the same for the drop point blade except you have to follow the curve while maintaining the knife at a consistent angle rather than treating it as two separate edges like the Tanto.



You do have to be careful on a blade with a distal taper like this one on a powered sharpener because it can be easy to grind your tip away.  Even with stones you have to be vigilant to maintain your tip.  Also, notice how even though I dropped my angle from previous sharpenings (20 degrees to 17.5 degrees) there is still some dye towards the back of the bevel at the ends of the edge on the red knife?  It's because of the guide I use with stones (Lansky system - you'll see it in a future entry) ends up being a variable angle.  So even though I set it at a 20 degree (ish) angle, in the center of the blade, at points further it was probably a couple degrees shallower. 

Also, my angles aren't precise.  I just throw them out for reference.  The scale on the Worksharp grinder was set to 17.5 degrees but who knows how accurate that is and that also relies on how close to perfectly horizontal I hold the blade and how much pressure I put on the belt with the knife.  The harder I push down on the belt, the steeper the effective angle becomes.  So my point is, I don't really care about the actual numbers.  I just know that if the scale is right and I was perfect and consistent in my orientation and method I have a 17.5 degree bevel on these blades.  That might be 16 degrees if I actually measured it or it might be 19 degrees.  I don't care.  All I care about is if I find this edge is too fragile, next time I'll bump the scale up a couple degrees or if this edge doesn't turn out as sharp as I want, I'll bump it down a bit.  The nice thing about having a scale, regardless of its accuracy, is that if I want to keep the same geometry next time I sharpen, I know where to set it.

So after working both edges up through the 12000 grit belt, I always hone the final edge on a leather strop.  I usually do that by hand but I bought myself a leather belt for this grinder a while back so this time I'm gonna try it out.

The belt seems really nice.  It's thick and has a good smooth texture and runs true on the wheels with no "thumps" at the seam.  The white compound that came with it was crap though.  I couldn't even get it to charge the belt.  So I pulled out my green compound which is what I have on all my strops and the belt charged up nice and evenly.  I ran the leather belt at the slowest speed and fortunately this grinder spins in the right direction so that it is turning away from the edge so I just used the same settings and method as I did with sharpening.

It was a winner!  I got nice polished appleseed edges on both knives that performed admirably at leaving bald patches on my arm and at slicing up a piece of notebook paper 😎

So there you have it.  That's how I sharpen knives that I prefer a convex edge on.  This thing lets me drop my angle from a flat bevel grind to get them a little sharper but the rounded bevel seems to make up for the durability in the limited testing I've done so far on the black knife.  I'll see how the red one holds up but it doesn't see as much use or get sharpened as often as the black one.

Here's a little tidbit on how I maintain my knives too:

I start by blowing them out with compressed air to get all the lint and dust out.  That's extremely easy with these open frame scales on these two knives.  But occasionally something will get into the pivot area.  If that's the case, I'll take the knife completely apart.

The oil and the little microfiber things are from a company called Knife Pivot Lube.  I love their oil.  I've always used light machine oil or gun oil on my knives but I liked the look of their swabs so I bought the kit.  The oil is super lightweight and gets easily into the pivots and leaves practically no residue.  

I use a swab and clean out any remaining dirt or lint around the pivot or lock.  Especially on the edge of the blade.  Then I take the oil (the needle dispenser it comes in is great too) and oil my pivot joints and the lock mechanisms.  Just a drop in each spot then I work the blade and the lock back and forth a dozen or so times and done.  Then I wipe a light coat of the oil on the blades.

Then check ALL my screws.  If any are loose, I remove it and put a dab of threadlocker on it before putting it back in.  Just make sure the threadlocker can't get to the pivot or lock mechanism on your knife.

Then I take one of the microfiber swabs and clean out all of the recesses on the Torx screw heads.  I don't want dirt to build up and get compacted in there and then have to scrape it out and scratch the screws.  Why?  I'm a little anal I guess.

And that's all she wrote for these knives.  For carbon steel or cheaper stainless blades or closed frame knives I'll do a little extra as far as cleaning them out, removing any rust, and corrosion protection.  But the coatings on these Benchmade knives and the "Grivory" scales remove nearly all corrosion issues so they are simple to maintain.

FWIW, I will heartily recommend Benchmade knives.  I have these two and a fixed blade Tanto and they have all become favorites since I got them.  In case you are wondering if they are worth the pricetag, I wholeheartedly think so.  They are well made, thoughtful designs and most are made in the US.  They also offer lifetime free sharpening.  So if you just hate sharpening, you can pay the cost of shipping at any time as long as you own the knife and they will do it for you.  And their PM steels are outstanding at taking and holding an edge and the coatings they use kicks would-be rust square in the butt.

Would I recommend the Work Sharp Ken Onion sharpener?  Maybe.  But honestly, not without the blade grinding attachment.  And it's by no means a necessity.  You can get great results with stones.  The biggest advantages are speed and the convex edge it gives.  But that's both a blessing and a curse because there are a lot of knives I have that I don't want that edge on.  If anyone has questions about it or want to discuss it further, feel free to post in the comments or shoot me a PM.  I bought mine with the attachment at Charles Neil's estate sale for a very nice price.  Otherwise, I probably wouldn't own one and if this one dies, I can't say for certain that I'd buy a replacement.  I will say it excels for most kitchen knives.  Everybody in my family periodically brings me kitchen knives to sharpen and while the convex edge isn't ideal for all of them, it is great for choppers and large slicers which seem to be the ones that dull most frequently.  So if you are the designated sharpener in your family, it might be worth your time!

As I said at the beginning, this is just one way I sharpen knives but there are other ways and I'll post an entry on those methods as they come up for me.  Thanks for reading and comments and questions are welcomed as always!


16 Comments

Great writeup, Kenny.  I have the same Ken Onion edition WorkSharp and the grinder attachment.  It's what I use on all of my knives.  I generally take it to 2000 grit and then finish on the buffer ala unicorn method.  I have the leather strop, but find the buffer does a great job.

Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

Thanks Rich.  I've studied the unicorn method but haven't ever actually tried it out.  I need to though, a lot of folks swear by it.
I use the Ken Onion knife sharpener for my edc. Its just the knife sharpener model not knife and tool. Its simple and effective. My knife gets used all the time while working. 
Friend of mine has Bench Made knives. The Bench Made knives don't seem to hold the edge very long or he just abuses them. My little Klein seems to hold the edge a lot longer.  
With Benchmade, you really have to select the right blade and steel for what you use it for.  If I was banging mine around on steel, it would chip.  The steel is too hard and brittle.  But it holds an edge for a long time.  My BIL turned me onto them when the Navy started using them as standard issue.  There’s also a lot of knockoff Benchmades out there.  A LOT.  And really good ones right down to tbe packaging.  So it’s possible your buddy thinks he has a Benchmade but doesn’t.  Especially if he bought it on Ebay or FBM.  China’s getting really good at that stuff…
He got it from bench made I think. He has a few of them. One weighs as hardly anything. Blade hasn't chipped. Letting it get to butter knife sharpness doesn't help either
Yeah the ones with the plastic scales are super light.  Even with a blade the size of my black one, I have knives half the size that are just as heavy.
The first time I picked it up I couldn't believe a piece of steel could weigh next to nothing. 
I believe they offer free sharpening for life in the price of the knives. I've seen them before, they are awesome knives, kinda rich for my blood though, and I don't carry a knife much, quickest way for me to lose one. I'm terrible with keeping a knife safe. 
That’s okay George I carry one for you😉  I carry both of these religiously.

The pricetag on the Benchmades isn’t that bad if you shop around for high end folders.  Like you, I don’t trust myself with a $600 knife.  But the weight, feel and Axis Lock on the Benchmades sold me.  I also have a couple of Kershaw Ken Onion knives that are excellent in a smaller package and pricetag.  

This is my little Kershaw that’s my EDC. It’s the only one I’ve found that I like, since it’s so slim. I’ve got a couple of them that float around in different pants. 

Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".

I like the assisted opening on the Kershaws Ryan and for the price, you can't beat them IMO.  Even the chinesium steels hold an edge pretty well.  My last EDC before the Benchmade was a Ken Onion Scallion with CF scales and Damascus blade.  It's a beautiful knife.
I don’t threat mine very kindly, so I enjoy the price. I love that they’re so slim and I don’t even notice them in my pocket. I do reverse the clip so that I’m pulling it out of my pocket in the working configuration. It’s a little dangerous when they’re new since they open up so easily. I’ve caught my pocket on the opening blade. Once they get a little dirty that stops and then they work perfectly. 

Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".

Ryan, I love Kershaw...fairly affordable and tough....they are my EDC
I was given an automatic Benchmade with my badge number and Rank once when I was promoted, that was my EDC on duty.  It looks like crap from carry and use but still functions like it was new.

Mike

I've got a little Gerber that if I have a knife on me, it's that one. Also have a variety of Morakniv's, many in sheaths that I use in the shop, and yard. Nothing if I lose it, will I lay awake at night thinking about where was I when....

I also have a scattering of Opneil's back in the shop. I like that twister to keep them open. Nothing worse than a knife folding closed on your fangers. Plus they are pretty easy to sharpen, hardly will hold an edge, but easy to sharpen.


My bugout could for sure use some of your caring attention.