Edge damage from feather sticking with a UF2, tips for improving technique?

I did have an FK2 in hard thin edge get stuck in a nasty burl of a tree limb that I was batoning (after several beers at the campfire). Long story short I had to baton the edgeside to back it out of the wood (not recommended) while enduring a few chuckles from my buddies. It did roll the edge but a few swipes on a stone and it was like new. I was amazed at its ease in recovery.
 
Naftoor said:
Thank you for all of your responses Nathan! It’s definitely a relief to know the knife can handle more then what I threw at it. I’ll sharpen it out and am looking forward to years of good work with it =D The only thing that surpasses the amount of knowledge you share with other knifemakers on the forums and the build quality of this knife is your customer support, can’t wait to own many more CPKs!
Click to expand...

I think Nathan wants your knife for testing to see if something was wrong with it. He wants to replace it as what you experienced is not typical for a CPK. If you've seen the hard use tests he puts the UF2 through, that is very, very light use for a UF2.

If you said you were feathersticking some rebar, maybe what you experienced is more typical. I think Nathan actually shaves metal in one of the vids to show the edge stability of his 3V protocol. Seriously, consider that Nathan is very interested to know if you have a very rare defect. As a previous Quality Assurance professional, getting the actual sample exhibiting "odd" results is important. But it's up to you if you keep it instead, of course.

My 1st thought would be wire edge so you're more than likely going to fix the problem with a resharpening. But I wouldn't pass on Nathan's offer either.
 
Rollercoaster said:
Thanks for that video.

I live in the greater NYC area and if I ever heard cicadas that loud I would shit.
Click to expand...

They were louder than me. You can literally barely hear me over the cicada.

It's so hot and humid here, you can hear it in the video.
 
Naftoor said:
Hey all! Sorry, didn’t expect this to blow up this way.

I should clarify I’m not saying anything about the knife or the steel, I believe both are exceptional and was assuming it was me being an idiot with poor technique! I have no reason to suspect the heat treat, I know these guys get batch processed so I figure if something had happened to a furnace during the heat treat it would be seen on other knives, obviously this seems to be highly unusual thus why I suspect it’s just me messing something up.

I definitely agree that a 2x4 isn’t exactly prime featherstick material, I was frankly excited to test the knife and had been watching a few too many bush crafters so so I grabbed what was on hand. Took one cut and when it occurred so easily I got carried away and continued for a dozen or two more.

Regarding the edge rolling, good to know it’s normal, thank you Tim! My background is mostly in kitchen knives where edge rolling is normally followed by chipping since they use much more brittle steels and heat treats in many chefs knives that can’t handle the plastic deformation long term. I used a hunk of jade ( a pretty slow stone to begin with) finished to sharpen at probably about 1-2k grit equivalent. I said stropping but I should probably clarify it was maybe 30% edge leading and 70% edge trailing strokes to try and realign the edge.

I was able to remove about 75% of the area that’s reflecting light, and it no longer can be felt under the thumb pad. I’ll try to attach a picture of the remaining area and the offending wood. In the side profile of the knife, my index finger is located at the rolled section. The lumber is pretty clean stuff, it’s been sitting in the basement for 5-6 years at least, worst it’s been exposed to is me (failing) to use it as a test for a reseated drill press chuck.

Not sure if I can upload pics without gold so here’s an imgur upload in the interim.(
https://imgur.com/a/cq9Q6rA
)

It was purchased new unwisefool, I’ve realized I am far, far, far too slow to grab CPKs on the secondary 😅
Click to expand...
that is not the picture of a 2x4 I had in my head 🤣
there is definitely something funky going on
 
Tim the Wizard said:
with great respect, a rounding and a rolling of the edge isn’t really edge damage if it did not chip. That’s just use. And, if it did not chip (you describe it as deflected - I’m assuming there’s a rolled edge and a little burr) then you should be able to knock off the burr or wire edge in 30 seconds or less with any grit stone or strop. Stropping on a stone that long could also round an edge. You might try marking the edge with a sharpie permanent marker and making sure you are applying the work where you need to mold the steel. Marker will then come off with isopropyl alcohol if needed. This is my experience and not a comment on yours. I’m sure you and CPK will sort it out. Good people and good product. can we get some feather stick photos?
Click to expand...
With respect, the edge damage might mean different things to different people. I would consider edge roll as a damage. To me, anything that can not be restored with a strop is edge damage and rolls (depending on the size) is even more difficult to fix than a chip using a strop.

Anyway, 60.5 HRC steel grounded with water cooling should not get an edge roll after feather sticking. Even O1 zero scandi will not get an edge roll when feather sticking 2x4 pine.
 
Last edited:
Nathan the Machinist said:
Click to expand...



Holy ****. 😳 The force in those first cuts made my stomach drop, and that was before the chopping started. I should probably stop treating it like it’s made of porcelain. That was amazing to watch!

Figured I owed ya’ll a follow up with another test here showing how it originally occurred, and testing another section of the blade.

Also a few images following the chopping. Definitely some edge deviation, but not enough to feel to the touch and I think that’s expected after a few good whacks!

I did a similar test with the last inch or so of the blade, and seemed to have no issues

https://imgur.com/a/TZH7AH2
 
I took the very tip off my fk about a month ago. ☹️

Must've been a buried nail or screw in the fence post I was taking apart. Other than that tiny instance (oh, and hitting a long staple with the edge, whoops) that knife has held up to all the use and what some might consider mild abuse I've thrown at it.
 
Nathan the Machinist Nathan the Machinist , yeah Im aware the knife could have hit a stone, or even the steel broadhead and blades themselves while digging it out of that log, I know full well what I can do to a knife when I’m out in the woods haha. The couple spots on my edge looked just like the ones in the pics shown by the other guys here, barely enough to snag my fingernail and they were super easy to take off with some passes on the Sharpmaker.

Here‘s a pic from back then that shows the one out near the tip. As I said though, I’ve used it plenty since then and I haven’t seen anything come up.

NDqI5FT.jpg
 
Naftoor said:
Holy ****. 😳 The force in those first cuts made my stomach drop, and that was before the chopping started. I should probably stop treating it like it’s made of porcelain. That was amazing to watch!

Figured I owed ya’ll a follow up with another test here showing how it originally occurred, and testing another section of the blade.

Also a few images following the chopping. Definitely some edge deviation, but not enough to feel to the touch and I think that’s expected after a few good whacks!

I did a similar test with the last inch or so of the blade, and seemed to have no issues

https://imgur.com/a/TZH7AH2
Click to expand...

You should not have that bright spot on that edge with that type of work. If it was my knife, I would not be happy with this. As you can see from Nathan video, the knife can take way more than what you were doing and would take no damage. By the way, use the edge of your nail to check for the damage, this way you can feel the damage that you can not see.

Try to light up the edge using a flashlight from top. Hold the flashlight from 1 o'clock and 11 o'clock direction perpendicular to the spine of the blade and check to see if you can see anything reflecting the light back apart from the damaged areas. If there is it means that there is a burr (wire edge?) left on the edge but still if you need a flashlight to check for the burr and if it is not something you can feel, then it means that the burr is very small and will not cause what you are experiencing with your edge. If it was any other maker, I would say sharpen the knife and give it an another go since most makers/manufacturers burn the edges and the edges becomes too fragile. But Nathan uses coolant when grinding and sharpening (as far as I am aware), so it is definitely not a burned edge.

I would seriously consider sending it back to Nathan. I think it would be beneficial for all the parties involved (including us) to know what's the problem with this knife.
 
murat1983 said:
You should not have that bright spot on that edge with that type of work. If it was my knife, I would not be happy with this. As you can see from Nathan video, the knife can take way more than what you were doing and would take no damage. By the way, use the edge of your nail to check for the damage, this way you can feel the damage that you can not see.

Try to light up the edge using a flashlight from top. Hold the flashlight from 1 o'clock and 11 o'clock direction perpendicular to the spine of the blade and check to see if you can see anything reflecting the light back apart from the damaged areas. If there is it means that there is a burr (wire edge?) left on the edge but still if you need a flashlight to check for the burr and if it is not something you can feel, then it means that the burr is very small and will not cause what you are experiencing with your edge. If it was any other maker, I would say sharpen the knife and give it an another go since most makers/manufacturers burn the edges and the edges becomes too fragile. But Nathan uses coolant when grinding and sharpening (as far as I am aware), so it is definitely not a burned edge.

I would seriously consider sending it back to Nathan. I think it would be beneficial for all the parties involved (including us) to know what's the problem with this knife.
Click to expand...

This. N Naftoor it is incorrect that some edge deviation would occur after a few good whacks into wood. I'm not joking or exaggerating. That's not common in other knives and especially in a CPK. And I wouldn't consider those good whacks. Seriously, you're still in light use territory for that knife.

I've done far more with my CPK Kephart, and it's a lighter duty knife. I've managed similar damage because I was using a railroad tie as a back stop to chop some wood on and failed to notice a spike in the tie until afterwards. The steel or iron I chopped into is far harder than what you are chopping.

Nathan designed that knife to dig into concrete, no joke, exaggeration, or funny business. It was a requirement for the UF2 for military clients, if I'm not mistaken from his video.
 
You must log in or register to reply here.
Back
Top