Community Sharpening Journal, Part 2

[horzuff]

I've been carrying and using the SPY27 stretch 2 xl lw for a couple weeks now and I was always surprised how well it cut absolutely everything despite not being that thin BTE. Yesterday I finally had some free time to sit down with my fixed angle sharpener to finally put my own edge on it (the factory edge was still ok, but after some stropping it was not coming up to hair popping sharpness anymore with stropping alone). That's when I found out what was the magic ingredient - the factory edge was way below 15dps on the straight part, more like 12-13, only going slightly above 15 near the tip.

On a different note, while I had the sharpener set up I put new edges on a couple other knives I've freehanded before and found out my manual edges are consistently about 16 degrees on the lock side and about 18 on the show side, deviating only at the last cm or so near the tip, where they always go up in angle, no matter what I try (at least on knives with prominent bellies). Pretty happy with the consistency, a bit bummed the angles aren't lower, more disconcerted yet by the discrepancy between sides even though I try my darndest to make the angles equal, and then there are the tips...

[Brock O Lee]

End of the factory edge. Reprofiling was quick and easy, and reminded me again how great Cruwear is to sharpen.

[Brock O Lee]

Another two...

I've used the Delica K390 quite a bit in the garage over the last few months. I plan to swap it with the Sage Maxamet to see how that holds up with similar use. I sharpened both to 1000 grit, the Delica @ 15 dps, the Sage @ 18 dps.



This was the first time I sharpened Maxamet, even though I've owned the knife for a long time (I have not used it much). It felt *hard* compared to K390, and took some time to cut a new bevel... I lowered the angle just a touch to even it out on both sides, perhaps 1-2 dps lower than factory. Started with 400 grit and switched to 1000 just as it started to raise a tiny burr in places. Fully apexed on 1000 grit with a very small burr. Deburred with 1 micron diamonds on basswood.

It took a good edge. It cuts cigarette paper cleanly, and pops arm hair effortlessly with and against the growth, but the K390 felt keener.

[Librarian]

For the first time I tried to sharpen CPM REX 121. I used silicon carbide stones. Diamonds or cubic boron nitride are not required to sharpen this steel. To be honest, I expected it to be more difficult

The cutting edge in an optical microscope (10*15=150X) after different stones, as well as the angles and number of passes per side.
F320 SiC - 16.8 dps - 50 pps

F600 SiC - 17.1 dps - 40 pps

F1000 SiC - 17.4 dps - 40 pps

Suehiro G8 (8000 JIS SiC)- 18 dps - 40 pps

[Scandi Grind]

IMG_20251023_161228.jpg
For the first time I tried to sharpen CPM REX 121. I used silicon carbide stones. Diamonds or cubic boron nitride are not required to sharpen this steel. To be honest, I expected it to be more difficult

Nice pics! I am always looking at my knife edges but I don't have a way to take pictures of them to share yet. One day I want to get a USB microscope thing.

[vivi]

getting some things ready for a weekend in some mountain wilderness.



dropped the CS trench hawk down to 15 degrees per side or so on my belt sander. deburred on diamond rods with the sharpmaker 15 degree slots, then got a cleanly shaving edge off my coarse brown rods using the 20 degree slots.

touched up the temp 2 with my fine rods. it's one of the only knives I run that polished. hair whittling sharp, compares favorably against my razor.

excited to head out and enjoy the views and maybe even see some snow.

[cabfrank]

That sounds like a beautiful weekend. Enjoy it!

[barnaclesonaboat]

Finally ditching the factory edge on my S90V M2. Brought up this decent polish at 24 degrees inclusive using a typical progression for me: Jende diamond plates at 120 (stock removal), 220 (shaping), and 600 (burr), followed by Jende resin-diamond stones at 15, 9, and then 3 micron. Skipped the strops for now because the thing is sticky-sticky sharp. Maybe I'll need to strop someday... I really do enjoy S90V immensely.

[JBoone]

IMG_20251023_161228.jpg
For the first time I tried to sharpen CPM REX 121. I used silicon carbide stones. Diamonds or cubic boron nitride are not required to sharpen this steel. To be honest, I expected it to be more difficult

The cutting edge in an optical microscope (10*15=150X) after different stones, as well as the angles and number of passes per side.
F320 SiC - 16.8 dps - 50 pps
320-50.jpg

F600 SiC - 17.1 dps - 40 pps
600-40.jpg

F1000 SiC - 17.4 dps - 40 pps
1000-40.jpg

Suehiro G8 (8000 JIS SiC)- 18 dps - 40 pps
8000-40.jpg

I have not yet sharpened mine. Have not used much but I need to change that.

[barnaclesonaboat]

Cool to see the edge images from your progression @Librarian Thanks for sharing.

This week saw the reprofile and first homemade edge on my PD1 Stretch 2 XL, a knife I have used a huge amount with the factory edge. I didn't even know if I would like the Stretch 2XL, but it has become my lightweight knife of choice since (along with a S2XL in K390). It got a 26 degree inclusive mid-polish edge, here; Jende and TSProf diamond plates from 120-600, then Venev 800 and 1500 diamond matrix stones, 1um GJ stroping.



I also brought out the K294 Mule for a refresh after it has been rocking the same 20 degree inclusive edge for a long, long time (many stropped-back tuneups). I freshened it at ~10.5 degrees/side to eat into some micro-chipped areas a bit more and it came out screaming sharp again... Venev diamond matrix 400, 800, 1500, with 3um and 1um stropping. I really enjoy K294 at steep geometries and I may even like it better than K390 in use and sharpening.

[SpyderEdgeForever]

What is the sharpest any of you got a VG10 blade?

[u.w.]

posted over in the Crazy Good Deals thread also.

HF has the four sided Diamond Sharpening Stone for $7.99 right now.

https://www.harborfreight.com/4-sided-d ... 92867.html

u.w.

[silver & black]

Can you re-profile a knife edge free hand? How do you know the angle? I have extensive experience sharpening woodworking blades, but they are angles I know. I re-grind primary bevels on my grider and then free hand sharpen from there. How do you make a different angle on a knife without a fixed jig?

[vivi]

Can you re-profile a knife edge free hand? How do you know the angle? I have extensive experience sharpening woodworking blades, but they are angles I know. I re-grind primary bevels on my grider and then free hand sharpen from there. How do you make a different angle on a knife without a fixed jig?

absolutely. I've reprofiled over 500 knives, machetes, axes, hatchets, shovels, scissors etc. by hand.

Just pick an angle and go at it. Match the angle to the tool and intended use, then keep your strokes as consistent as possible.

that harbor freight stone mentioned above is a decent starting point for this. even better are the chef knives to go diamond flattening plates, or once you really feel confident - a belt sander.

[Scandi Grind]

Can you re-profile a knife edge free hand? How do you know the angle? I have extensive experience sharpening woodworking blades, but they are angles I know. I re-grind primary bevels on my grider and then free hand sharpen from there. How do you make a different angle on a knife without a fixed jig?

I freehand basically everything and rarely keep a factory angle. What I like is using little angle wedges that I set the knife on to get a feel for my desired angle then I just hold that as I go re-checking my angle against the wedge as often as I feel necessary. If I am being very careful that is typically about every 6 strokes. Bear in mind I typically do multiple strokes per side until I raise a burr, so I am not flipping the knife back and forth every stroke until I get to the final steps which should be just one stroke per side. Doing multiple strokes without changing sides makes it easier to keep the angle, then when I start alternating I check my angle before every stroke.

[silver & black]

Vivi and Scandi... Thank you for the input. I'll try this on a couple of cheap knives I've had for years before attempting it on my "good" knives.

I have Atoma diamond plates in 140 - 400 - 600 and 1200. A Trend diamond plate in 300 - 1000. I have quite a few Shapton glass spritz and go stones also, from 4000 to 16000.... and a collection of all kinds of Arkansas stones. I'm sure I can sharpen aything with this assortment. I'm not planning to purchase any more sharpening stones for this foray into the knife world.

[vivi]

those coarse atomas will surely do the job.

what scandi mentioned about working one side before switching to the other is spot on. reprofiling is different than sharpening. sharpening I switch sides every stroke - reprofiling I finish one side before starting the other.

I wouldn't stress too much about the numbers.

The way I do it, is I keep a couple thick wooden sticks in my garage. New general purpose fixed blade knives, folders & machetes, I try making some thin wood shavings with one of the pieces. I'll touch up the apex a bit first if needed, as I'm trying to test geometry rather than out of box sharpness.

If they carve well, I typically leave the edge angle as is. Very few do though. Some recent ones that did are my winkler belt knife, buck 110's, and spyderco temperance 2. Just about everything else needed some thinning to reach my standards on the wood cutting test.

From there I just bring the edge back a little thinner, apply a shaving sharp apex, then test again.

Over the years I've found my sweet spot for performance and durability, so that's usually the end of it. After I figure out a good angle for the knife I polish up the apex to my desired level, and put it to work.

I don't worry about whether it was an 8 degree per side edge, 10dps, 12dps etc. I just go by feel. The only time I concern myself with numbers is when discussing my edges online, and I have a few low tech ways of estimating the edge angle. I press the knife edge into clay, take a photo of the impression, then measure the angle on my PC.

Some knives like kitchen knives I'll just use for their intended role. If a new gyuto is cracking apples and carrots more than expected, maybe I'll thin out the entire geometry instead of just the edge.

Often times better results can be acheived that way, but it takes more skill and more expensive tools to do efficiently. I have some SRK C fixed blades where I reprofiled the entire blade on my belt sander, and those definitely have some advantages over simply thinning out the very edge. But I wouldn't be comfortable trying that on a $400 winkler or $250 gyuto, and on knives with DLC coatings etc. you can certainly kiss the coating goodbye.

So both types of thinning processes have their place in my eyes. A lot of Spydercos have wonderful overall geometry, but the edge bevel is just a bit thicker than I prefer. Maybe 18 degrees per side instead of around 12 dps. For something like that, using diamond benchstones to apply a thinner bevel is plenty good enough, and a belt sander applied to the full primary grind is likely overkill.

[silver & black]

Thank you so much for your input. I use my knives generally for work... which is cutting poster board templates, cutting wood veneer, cutting plastic straps on rolled veneer and laminate and opening cardboard boxes and then slicing them up for disposal. I think a lower deg. edge would be more suited to what I do with a knife..... say 15 -13 deg.???

[Scandi Grind]

I've never met a knife that couldn't handle 15 dps in my use, but YMMV. The only foolproof way I know to find the ideal edge angle is to thin a bit, test on the roughest task you have for your knife, and if it doesn't take damage repeat. Once some chipping or rolling occurs, you can micro bevel it to bring it back to stable most of the time, then sharpen at a slightly more obtuse angle the next time you re-sharpen.

For me the roughest task I have for a knife is carving hardwood. I redid the entire bevel on a fixed blade using a file last year and zero ground it initially. It cut like a demon but chipped on some hardwood. I repaired the chipping and kept adding a more obtuse bevel until it stabilized. Now instead of a zero grind I have a sabre grind with a very thin secondary bevel run at the minimum angle I know it can take while being stable for my use.

Most of my knives though I take them down until I am happy with whatever task I use them for most and don't go quite so far as to find the limit of their potential. Others get thinned out gradually over several sharpening sessions so long as I don't see any damage. For my Endura I am currently running somewhere between 12-14 dps, but bear in mind freehanding adds some convexity to the edge, so it is a little more stable than something off of a fixed angle system.

[pinchyfisher]

I agree with Scandi regarding using wedges to hold consistent angles.

I also think the best advice you'll hear regarding what apex angle to use for your specific use/knife/steel is go more acute until premature edge failure due to rolling/microchipping, then go a bit more obtuse.

Keep notes (my opinion). Learn to tell apex rolling vs microchipping vs wear (still not a pro).

You have the best tools for the job and a good skill foundation with woodworking tools. Have fun!