Police 4 K390 SE Testing Log

[Craiger12]

I definitely think I would want to reprofile to 15*. I'm currently working my way through reprofiling my Salt 2 SE to 15* and it's quite a chore. This is my biggest hang-up with going to K390 in SE, as well as edge durability of course. I know LC200N is much tougher and less prone to chipping, but I like the idea of improved edge retention and also prefer the more solid feeling of the liners in the Endura compared to the linerless Salt 2 and Pac Salt 2. I'm sure durability isn't an issue with the Salts, but there's just something about that heavier solid feeling like I get when I handle my new Stretch 2 SS K390 - very confidence inspiring.

[The Meat man]

David, you're reprofiling that to 15 degrees, correct?

[Evil D]

David, you're reprofiling that to 15 degrees, correct?

Correct. The initial angle was something between 15 and 20 degrees, probably closer to 20 degrees.

I'm heading to bed now (12 hour day from ****) but I'm sure I'll be up and at it early as always and I plan on starting this other thread in the morning. I don't wanna detail this thread. Sorry to leave you guys on a cliffhanger

[The Meat man]

David, you're reprofiling that to 15 degrees, correct?

Correct. The initial angle was something between 15 and 20 degrees, probably closer to 20 degrees.

I'm heading to bed now (12 hour day from ****) but I'm sure I'll be up and at it early as always and I plan on starting this other thread in the morning. I don't wanna detail this thread. Sorry to leave you guys on a cliffhanger

That looks pretty thin for 15 degrees. Very nice.
Hope your day goes better tomorrow!

[Evil D]

OK so unfortunately the reprofile has taken a turn for the worst.

As in, I've just about sharpened off the first section of serrations





If you go back and look at previous posts you'll see where I mention that the heel of the edge was going much faster than the rest of the blade, I've had this happen on pretty much all my knives but it has never been a problem until this knife. If you look at some of those other pics you can even see that the points started rounding off, and while that's usually not a big deal and something that I actually prefer, I didn't expect it to progress to this point.

You can see in this pic, I'm not quite there on the front of the blade, but I suspect that eventually once the whole blade is reprofiled, this thing is going to essentially be a "micro Kris".




This is where I'm at with 7200 passes.



And while that looks to be getting close, there are surely a few thousand more passes required to get the rest of that marker removed from the edge.

So. What to do now? Why did this happen? Did I get carried away with the diamond/CBN rods? Why haven't I seen this on other knives? Is it the geometry of these serrations? Is it somehow related to the steel itself? Is it just user error?

I'll keep plugging away at it, no sense in "wasting" an otherwise perfectly good knife. I'll be able to put an edge on this thing one way or another, regardless of how much it resembles a serrated edge in the end. If all else fails my Edge Pro can make this into a chisel grind plain edge quite easily.

[Evil D]

Oh, and it's a bit of a burr nightmare. I can't say how easily it is to remove and clean up just yet, but it's pretty bad. It chips and breaks off just from touching it. Sal said something in a post about taking this very slow and doing it through touch up sharpening and I think he's right with this steel. The combined time it takes to reprofile it and the potential for either grinding off the teeth or ruining your Sharpmaker rods is pretty high all around. It probably shouldn't need to be said but this steel and serrations is quite an AFI combo.



What I'm hoping is that once I have the whole edge reprofiled, as I sharpen and do micro bevels the shape of the serrations comes back out. I saw this happen on my Autonomy after chipping off several of the teeth, I expected the points to just be gone and never really come back but if you never knew they had been chipped you wouldn't know it. We'll see how it goes I guess.

I do believe there is some user error happening here because I have a similar issue happening with my Caribbean, the serrations have gotten really mellowed out on it lately. It may just be that as I do this more and more I'm getting more comfortable with it and rushing through it more. I don't feel like I'm going any faster but the more you do it the quicker you get without even trying. The bad news is, with as many passes as this takes, if you actually do take it SLOW, it's going to take an eternity to get this steel reprofiled.

[Craiger12]

If I do end up grabbing the Endura SE in K390 it looks like I'll be sticking with a 20* egde.

[yablanowitz]

Just a suggestion from someone who has screwed up his fair share of serrations, but it looks to me like you've had your blade "pitch" wrong. It looks like the tip has been too high, so the centerline of the scallops has not been parallel to the Sharpmaker rods. I've been working on mine for a while, and the heel and tip have been lagging a bit behind the center.

Not having the pitch held correctly is how I rounded off the teeth on my user C44 Dyad.

[Evil D]

Just a suggestion from someone who has screwed up his fair share of serrations, but it looks to me like you've had your blade "pitch" wrong. It looks like the tip has been too high, so the centerline of the scallops has not been parallel to the Sharpmaker rods. I've been working on mine for a while, and the heel and tip have been lagging a bit behind the center.

Not having the pitch held correctly is how I rounded off the teeth on my user C44 Dyad.

Thanks, I'll most likely get another knife in this steel eventually and I'll keep this in mind when I do.

[Brock O Lee]

Interesting observations about K390 and SE Evil D...

As a point of reference on the steel, I managed to chip my straight spine Stretch by hitting a staple in double-walled cardboard. It is reprofiled to 12 dps with a 15 dps micro bevel. I did not experience huge issues with the burr.





Not a train smash, it will sharpen out.

Looking forward to see where this SE adventure takes you! 6000-8000+ passes, man that is a mountain to climb.

[Evil D]

Looking forward to see where this SE adventure takes you! 6000-8000+ passes, man that is a mountain to climb.

It's pretty stupid if I'm honest, and now that I think about it yablanowitz is absolutely right, I haven't been paying attention to the angle of the blade at all, and this is my first Police 4 so I'm certain I've been holding it wrong and I'm certain that has added a lot of unnecessary passes to the process. As crazy as it sounds I may even bail on this knife and start fresh with another one, I've been thinking about that chisel grind PE idea and I kinda want to try that, or I may only grind off the serrations on the heel, we've been talking about a combo edge with the serrations towards the front of the blade and this could be a way to try that out.

[Doc Dan]

I think a combo edge is a good answer. I like combo edges in general if they are done well. They are very useful.

[yablanowitz]

David, if you look at the scratch pattern in your close-up edge pictures, you can see your scratches are a much different angle than the original grind marks. Part of that is from the blade pitch and part of it may be from the way you do your strokes. If you are going strictly heel to tip and running the whole length of the blade on each stroke, that's the scratch pattern I would expect to see. I've learned the hard way to alternate heel to tip and tip to heel, and to use multiple stokes to go the length of the blade so I'm going more down the rod than across the rod (if that makes any sense to you). I'll see if I can get a macro shot of mine after my next diamond session.

[Evil D]

David, if you look at the scratch pattern in your close-up edge pictures, you can see your scratches are a much different angle than the original grind marks. Part of that is from the blade pitch and part of it may be from the way you do your strokes. If you are going strictly heel to tip and running the whole length of the blade on each stroke, that's the scratch pattern I would expect to see. I've learned the hard way to alternate heel to tip and tip to heel, and to use multiple stokes to go the length of the blade so I'm going more down the rod than across the rod (if that makes any sense to you). I'll see if I can get a macro shot of mine after my next diamond session.

I think part of it may be that I was trying to get the whole blade across each stroke and it's a lot of edge length to do that. I've tried alternating passes heel/tip and tip/heel in the past but didn't do it on this knife.

[TheGiant80]

So is this model a must-buy? Would you suggest sticking to PE?

[Evil D]

So is this model a must-buy? Would you suggest sticking to PE?

I definitely think it depends a lot on how you plan to use the knife and how dedicated you are to the reprofiling process and all that. I think I'll be looking for this steel/edge combo in something a tad smaller, I'm really hoping for a Rock Jumper but I may also get a Stretch. I do really like the Police 4 though. If this steel opens up to Golden models I would instantly buy a Native Chief in SE K390.

[yablanowitz]

I've almost got mine down to 15° (probably 18° to 20° total included angle), and it is quite a demolition tool. I don't know if it is a "must buy", but I like it. I like it a lot.

[Wartstein]

It's pretty stupid if I'm honest, and now that I think about it yablanowitz is absolutely right, I haven't been paying attention to the angle of the blade at all, and this is my first Police 4 so I'm certain I've been holding it wrong and I'm certain that has added a lot of unnecessary passes to the process. As crazy as it sounds I may even bail on this knife and start fresh with another one, I've been thinking about that chisel grind PE idea and I kinda want to try that, or I may only grind off the serrations on the heel, we've been talking about a combo edge with the serrations towards the front of the blade and this could be a way to try that out.

I am certainly sorry for you that this happened, but at the same time really thankful that you write about the reprofiling process in such detail and especially that you share that mistake (thanks also to Yablanowitz of course for pointing it out!).

I´d never considered myself that a consistent angle of the blade is of real importance when reprofiling SE!
Clearly one of those things one does not think of at all, but which seem totally logical when someone tells you about it.

[VooDooChild]

So is this model a must-buy? Would you suggest sticking to PE?

Do you have a police 4 yet? My reccomendation is still the police 4 lightweight in plain old vg10.

Ive got a police 4 lightweight vg10, police 4 lightweight k390 pe, and police 4 hap40.

I wanted this knife but this thread has actually kind of turned me off from it. I want serrations but I dont want tool steel serrations, if that makes any sense.

If Im honest I would prefer a police 4 with a vg10 serrated edge.

[Evil D]

So is this model a must-buy? Would you suggest sticking to PE?

Do you have a police 4 yet? My reccomendation is still the police 4 lightweight in plain old vg10.

Ive got a police 4 lightweight vg10, police 4 lightweight k390 pe, and police 4 hap40.

I wanted this knife but this thread has actually kind of turned me off from it. I want serrations but I dont want tool steel serrations, if that makes any sense.

If Im honest I would prefer a police 4 with a vg10 serrated edge.

Most people would probably have a better relationship with VG10, but I think there's a lot of potential here for crazy edge retention. I haven't closed the book on this just yet, I just haven't figured out what to do next.