UKPK thinned out just a tad

[vivi]

Just took my UKPK to 8-10 degrees inclusive judging by eye.







Still working on it. The microbevel isn't so micro right now either, was trying to take out some of the edge damage. This geometry + a hair whittling sharp edge is truly for the cut connoisseur.

[Fred Sanford]

Vivi,

Nice pics. Please forgive me but I don't understand what that helps. I honestly don't, so maybe you could tell me. If I should make a seperate thread outside of this thread just let me know.

Does that just make for less resistance with what you are cutting? How much different does it feel from the factory edge?

Thanks.

[vivi]

Vivi,

Nice pics. Please forgive me but I don't understand what that helps. I honestly don't, so maybe you could tell me. If I should make a seperate thread outside of this thread just let me know.

Does that just make for less resistance with what you are cutting? How much different does it feel from the factory edge?

Thanks.

It is to improve cutting performance. The thinner the blade is, the less resistance there will be in a cut. It takes very little mass to perform all my usual cutting tasks. Something like an Opinel or SAK is robust enough for the cutting I do 95% of the time. I wouldn't recommend something like this for a knife that sees rough use, but most knives in my experience can safely be taken to 16-20 degrees inclusive with a microbevel and stand up to anything you'd expect a knife to take.

How different it feels depends on the knife. On my Cara Cara that I reground flat to the stone, the difference was dramatic. On some knives, like a Caly 3 that was ground pretty acute from factory, the difference won't be as extreme. It's worth it to me though, much less force is needed to cut things. Take a cheap Byrd like the FRN Robin and reprofile it flat to the stone and apply a microbevel, then go cut some cardboard and you'll see what all the fuss is about.

[mrappraisit]

That's wild Vivi - Once you've got the edge back it will truly be a super slicer.

[Fred Sanford]

Thanks Vivi for the explanation. That's exactly what I wanted to know.

I just may try that out as I've never owned a Byrd knife anyway. I have a Coarse DMT stone, think that will do fine?

Thanks man.

[MAT888]

VIVI,

Chips and dings can be taken out with a 90 degree angle cutting in the stone on a coarse diamond benchstone. About 20 passes should do on a XXC DMT...

I would have left the stock at 15. Microbevel does the cutting and back bevel stock doesn't make much difference unless it has a 4/5mm thick spine. :cool:

[vivi]

VIVI,

Chips and dings can be taken out with a 90 degree angle cutting in the stone on a coarse diamond benchstone. About 20 passes should do on a XXC DMT...

I would have left the stock at 15. Microbevel does the cutting and back bevel stock doesn't make much difference unless it has a 4/5mm thick spine. :cool:

It's mainly just an experiment to see how thin I can take S30V before it's too weak to be an EDC. I'm going to keep grinding until there is no microbevel and try cutting a few things with it like that to see what happens under magnification at the edge. Then I'll put on my usual edge.

I've already tried it on some carrots and it's different than before. On certain materials you can really notice the thinness as you cut.

[Spydiman]

Do you carry around another knife in case you DO run into something harder to cut?

[vivi]

Do you carry around another knife in case you DO run into something harder to cut?

No. I usually have a SAK or LM Squirt on my keychain if it came down to it, but I've never encountered anything I've had to cut that the UKPK couldn't handle with it's last edge (~8 deg. per side or so). My usual EDC tasks aren't too rough, just cardboard, food prep, wood, vegetation, mail, opening boxes and packages etc.

[LowTEC]

at 40 degree , my military edge gets dull after cutting on those regular plastic cutting board for a day or 2, your UKPK might get dull in couple slices on the cutting board with that kind of an angle (<20?). Wow :D

[vivi]

at 40 degree , my military edge gets dull after cutting on those regular plastic cutting board for a day or 2, your UKPK might get dull in couple slices on the cutting board with that kind of an angle (<20?). Wow :D

I've had a different experience. I've tested out thin edges (6-10 deg per side + microbevel) chopping wood, batoning wood, cutting thick plastic, cutting knotty wood, batoning through power cables cat5 cable and coax cable etc. along with my usual EDC tasks. The only thing that's visibly damaged it was the coax cable, everything else it handled without harm.

http://www.youtube.com/watch?v=1SFG9-6Bmp0 - Very light chopping, cutting a PC power cable. Here is a link to what the knife looked like at the time. http://img141.imageshack.us/img141/4568/ukpk1bq1.jpg

http://www.youtube.com/watch?v=Fl6vNtnOEwE Here it is cutting a box.

Still shaves. http://www.youtube.com/watch?v=ryfslOiA9eY

[Left Hand Path]

That looks like a high-performance edge, Vivi. Thanks for posting the pictures. I thin the edge (re-bevel) on every knife I get, but I haven't taken any quite that far.

I am curious - what caused those chips in the edge?

[vivi]

That looks like a high-performance edge, Vivi. Thanks for posting the pictures. I thin the edge (re-bevel) on every knife I get, but I haven't taken any quite that far.

I am curious - what caused those chips in the edge?

I decided to go this thin because I haven't found the point that's too thin to stand up to EDC use. Once I do, I'll edge my knives right above that point, to get the best cutting perfomance I can while keeping it strong enough to not baby.

http://www.bladeforums.com/forums/showt ... p?t=561980

Here is the post, since you have to register to read that forum I think.

I was looking for things to test the thin edge of my UKPK on, to see what would damage it and how much. It had handled chopping and batoning wood and cutting through power cables fine, so I didn't expect this much damage from coaxial cable. I tried out other knives, each with a much thicker edge and most with a tougher steel. Many of the knives received roughly the same amount of damage, but the Spyderco Mule hardly looked touched. The knives were hammered through the cable with a wooden baton. The large chip in the UKPK is from the first attempt where no baton was used and I tried to use normal cutting technique. Edge geometry didn't seem to influence the results as much as I expected.


UK Pen Knife (S30V)


Kabar TDI (AUS8)



Tenacious (8Cr13MoV)



Mule (51200)



CRKT (AUS6)

[vivi]

Worked on my UKPK tonight along with a few others. Here's the setup I was using. 100 grit sanding belt glued to a dvd case, DMT fine and a strop. I've been using edge leading strokes for the microbevel ever since I tried sharpening that way. I get a cleaner edge more quickly than edge trailing.



http://www.youtube.com/watch?v=3kT5zIAptbc

[Left Hand Path]

That looks really good. I bet that is quite the cutter. Looks like the edge damaged was removed or at least reduced.

Do you know the approximate edge angles on that one for primary and micro bevel? Do you use calipers or anything to measure thickness at the shoulder?

Do you have any videos of you sharpening? I always apply the primary bevel freehand, but I usually use the Sharpmaker for the micro. Yesterday I sharpened a Victorinox kitchen knife totally freehand using DMT diamonds and then the Spyderco Profiles. It was a great feeling to get a shaving sharp edge freehand. I am curious how you orient the stone while finishing on the finer grits? Do you alternate sides with each stroke?

How much width (if any) have you lost during all the reprofiling/rebeveling and removing the chips? I have never handled a UKPK, but I am familiar with the Caly 3 and on the 2 that I have seen the edge/tip was not covered all that much by the handle when closed. It just seemed to me that it wouldn't be able to lose much blade width before the tip would be exposed when the knife was closed.

[vivi]

That looks really good. I bet that is quite the cutter. Looks like the edge damaged was removed or at least reduced.

Do you know the approximate edge angles on that one for primary and micro bevel? Do you use calipers or anything to measure thickness at the shoulder?

Do you have any videos of you sharpening? I always apply the primary bevel freehand, but I usually use the Sharpmaker for the micro. Yesterday I sharpened a Victorinox kitchen knife totally freehand using DMT diamonds and then the Spyderco Profiles. It was a great feeling to get a shaving sharp edge freehand. I am curious how you orient the stone while finishing on the finer grits? Do you alternate sides with each stroke?

How much width (if any) have you lost during all the reprofiling/rebeveling and removing the chips? I have never handled a UKPK, but I am familiar with the Caly 3 and on the 2 that I have seen the edge/tip was not covered all that much by the handle when closed. It just seemed to me that it wouldn't be able to lose much blade width before the tip would be exposed when the knife was closed.

Edge damage is mostly gone, slices much more smoothly now.

I don't know what angles I used. I put the main bevel on keeping the spine within 1 mm of the stone. I go pretty obtuse on my microbevels, so I'd guess 30 degrees inclusive for it.

I have a video of my sharpening method I'll link to at the end of this post. I need to shoot a new one because you can't see what I'm doing realy well. When putting on the microbevel I use edge leading strokes on a DMT fine stone, using light pressure, gradual getting lighter and shortening my strokes as well, so that each stroke towards the end of sharpening I'm barely touching the blade. I alternate on every stroke. When I think I'm done, I wipe off the blade, check for burrs, then feel the edge and see if it pops arm hair. Sometimes I check under 100x magnification too. Then I just strop using very light strokes at the same angle I used for the microbevel.

I haven't lost much of the blade profile yet. If what you talk about becomes an issue I might try modifying the blade length. I've always wanted a UKPK with a slightly shorter blade as a companion to my Military, but then saw the Urban and decided that would do it just as well.

http://www.youtube.com/watch?v=wT0MLZvEDHc

[Left Hand Path]

Thanks for the info and the video, Vivi. That is a really thin primary bevel! What do you think of the 100 grit belt compared to one of the coarser DMT stones? I also use a pretty obtuse microbevel - it is easier to apply and I think it is the primary bevel that makes a big difference in performance, not the micro.

As far as modifying blade length, I hope I never have to, but if I do - do you think a XX-coarse DMT diamond stone would work to grind down the spine and shorten the tip by a few mm?

[vivi]

I don't own a coarse DMT so I can't say. I plan to order some in the future, I'm happy with the fine stone I have.

[vivi]

Here are some video links. In the first video where the edge is catching that's from a poor push cut attempt and / or the damage that was already there. The knife didn't sustain any new damage, it only lost a bit of sharpness from cutting the can. Still took hairs off my arm and obviously could slice paper.

http://www.youtube.com/watch?v=yDdk0IJYXyQ
http://www.youtube.com/watch?v=2io7hAL0mcc

[rlw1979777]

Well its definatly different. At least you got a one of a kind.