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This will be an ongoing thread as usual, I'll carry this knife as much as I can in the upcoming weeks/months and see how it fairs. Unlike my failed Jumpmaster 2 thread (sigh) this should be an easy one to carry everyday aside from a short vacation coming up where it's going to be illegal to have with me but that's only for like 4 days so it shouldn't be a big deal.



So lets get right to initial impressions.



Right out of the box, we have a pretty interesting note from Spyderco about not letting it rust. Also of note is a silica packet inside the baggie, and the whole blade is covered in a grease or oil of some sort. When I first looked at it, some spots of the blade almost looked like they were patinaed already but it's just the grease. You have to consider the potential for knives like this to sit on warehouse shelves for who knows how long and potentially rust, so it's smart that they slather them down before shipping.



Aaaaaand then I noticed the blade is super duper off center:





Ok.....don't panic...


A quick note about knife construction and blade centering, as I understand it.

These knives have what I (respectfully) see as a somewhat obsolete construction method. What I mean is, it uses a "pin and screw" construction holding the whole thing together where one side of the handle has a dome head pin with a screw that threads into it from the opposite side. This was very common 20 or so years ago with Spyderco but has since largely been replaced on a lot of models (especially in Golden it seems) with "screw/pin/screw" style construction where each side of the handle has a screw threading into a center pin much like you see with most pivot pins. What you tend to get with this (again, as I understand it...maybe Sal can verify this) is it's VERY easy to throw the parallel balance of the scales/liners/blade off when assembling the knife and if a very careful torque sequence isn't followed while tightening the screws, everything is basically warped and that causes the blade to not be centered.

Here I've got each side of the blade laid down on a flat cutting board




As far as I can tell the blade is not warped/uneven ground at least as close as my eyeballs can tell.


So here's how you center up the blade. Loosen all the scale screws and in really bad cases even the pivot screw (I didn't need to with this one) and hold the knife in your hand in such a way that you can "flex/bend" the knife and you'll see that depending on which way you flex it, you can move the blade centering around:



Then, while holding/flexing it this way, tighten down all the scale screws. I usually work from the center of the handle outward. There is probably a proper torque sequence for this much like an engine's cylinder head but this worked for me.




If nothing else even if your blade is a wee bit warped, you can do this and center the blade tip up enough to not make yourself crazy over it.


Serration grind comparisons


I'll add to this part of the post as I can with other knives. The problem I have is that almost all of my other SE knives have been reprofiled, so it's hard to give you a fair side by side comparison. Here are some shots next to a factory grind Police OG.


Police 4 on top, Police OG on bottom:




Right out of the gate I can tell you the blade grind is pretty thin, obviously thinner than that low hollow Police OG, but I'll have to see if I can figure out about what the serration grind angle is. You can see that it's a good bit shorter in height which could be due to the thinner behind the edge thickness of the blade grind or due to a much steeper serration angle grind (hopefully not that). We'll see.

What about those grind lines in the serrations though? I really would love to see how these are ground, I don't think they came off a grinding wheel because they are absolutely perfect and insanely uniform in shape. The whole bevel is so even from start to finish, this has to be done by a robot or CNC or something (now that I look closer, I see the Police OG has those line in the serrations too but not as visible...on the P4 you can even feel them with your fingernail). Again, maybe Sal can chime in with a little info here because I've never seen serrations ground like this. They're somewhat short in length, maybe even a bit shorter than the Police OG. Shorter length serrations can be good or bad depending on what you like, shorter length does mean there's more of them in a given blade length.

Police 4 on the top in all of these pics:












Behind The Edge Thickness

Well, I suck with calipers so take this with a healthy spoonful of salt, but I'm seeing around 0.53mm at the top of the points between the scallops and about 0.65mm at the top of the scallops. The Police OG measures in at 0.78mm at the points and 1.40mm atop the scallops. They measured about the same all along the blade, at least as accurately as my shaky hands can manage. And again, I'll dig out some other knives that have factory bevels and see if I can get some more numbers to compare but I don't have much and I think the ones I have are much older models that may not tell us much. Someone with a factory bevel grind Caribbean get us a measurement to compare to this.

I'll leave ya'll with that for now. Time to go cut some stuff

Bevel angle appears to be in the neighborhood of 20 degrees (40 slots on Sharpmaker).


Here's a couple light passes on the 30 inclusive slots (15 degree per side). You can see the rods were hitting right at the top shoulder of the bevel:



Here's a couple passes on the 40 inclusive slots (20 degrees per side). It's hitting more of the whole bevel evenly and if I gave it a bit more pressure it probably would have hit pretty flat on.




I'll use the factory bevel for a while and then see about thinning it out down to 15 degrees.

Thank you for the time, and effort you are putting into this. This is my 1st police, 1st K390 model, and 1st serrated edge Spyderco. Mine should come tomorrow. I'm looking forward to this discussion!

Just FYI, Sal has stated in the past that the serrations are ground on a shaped wheel, which grinds them all at once. The wheels are dressed as they wear, so the edges will vary a bit from piece to piece.

yablanowitz wrote: ↑

Fri Oct 01, 2021 12:48 pm

Just FYI, Sal has stated in the past that the serrations are ground on a shaped wheel, which grinds them all at once. The wheels are dressed as they wear, so the edges will vary a bit from piece to piece.

Yeah that's what my understanding was, these just seem really different compared to all the rest that I have. Maybe this is just the first run off a brand new wheel or something. The grind lines inside the serrations are so strange.

Very interesting! Thanks for putting this together. I'll definitely be watching this thread and seeing how it holds up for you.

Added 8 more comparison shots in the first post, but as I'm taking these I'm wondering what use they'll be to anyone


Suffice to say the blade grind is a good bit thinner behind the bevel than most. Most of the SE knives I've sharpened were closer to the 20 degree (40 Sharpmaker) slots than the 30 slots, with the exception of the ARK which is the thinnest ground SE blade I've seen to date and micro bevels when using the 30 slots, so the bevel is ground somewhere lower than 15 degrees and is very very thin at the apex. If I can someday manage to thin this out to a 15 degree bevel, and assuming the edge doesn't become too fragile at that point, this knife is going to be stupid good.

Oh boy....this is gonna take some work. I thought S30V took forever to grind but geez. This is probably 100 passes on diamond and CBN rods just to see if either one cuts better. I'll do this one a little at a time in stages lol.





But rest assured it's definitely removing steel.




This has me thinking I really don't wanna have to fix a chipped edge in this steel.

The k390 P4 ltwt se is on my list. I have to slow down my purchases for a while though so this thread is nice. Plus I have the pe version and it is pretty great.

yablanowitz wrote: Just FYI, Sal has stated in the past that the serrations are ground on a shaped wheel, which grinds them all at once. The wheels are dressed as they wear, so the edges will vary a bit from piece to piece.

So yeah, but also I think the serration style changes depending on which model it is and what steel it is, and of course what blade shape it is. Older models with vg10 always seem to have that really pointy higher ground serrations. (Enduras, rescue 3, etc)
H1 serrations all seem to be very similar. The serration size changes depending on the size of the knife but h1 serrations of a similar size all seem very similar to me.
Lc200n is all over the map. Caribbean serrations are different from Pacific salt are different from native 5.

VooDooChild wrote: ↑

Fri Oct 01, 2021 3:12 pm

The k390 P4 ltwt se is on my list. I have to slow down my purchases for a while though so this thread is nice. Plus I have the pe version and it is pretty great.

yablanowitz wrote: Just FYI, Sal has stated in the past that the serrations are ground on a shaped wheel, which grinds them all at once. The wheels are dressed as they wear, so the edges will vary a bit from piece to piece.

So yeah, but also I think the serration pattern changes depending on which model it is and what steel it is, and of course what blade shape it is. Older models with vg10 always seem to have that really pointy higher ground serrations. (Enduras, rescue 3, etc)
H1 serrations all seem to be very similar. The serration size changes depending on the size of the knife but h1 serrations of a similar size all seem very similar to me.
Lc200n is all over the map. Caribbean serrations are different from Pacific salt are different from native 5.

I think it's more a regional thing than anything else. The Seki serrations tend to be one way, Golden another, and Taiwan something else.

In general I have found that serrations the Chinese Byrd knives to be by far the most mellow and wavy, as opposed to snaggy and pokey. I wish that all Spyderco SE knives were similarly done.

Will be really interesting to see how it holds up to one of David's torture tests. Chips in K390 are no bueno. Serration patterns may be regional or dependent upon steel selection, but I gotta say that I'm very impressed with the factory teeth on my serrated UKPK Salt.

Is it strange that I’m reeeeally glad this thread has commenced? No doubt it’ll be the deciding factor whether I take the plunge on this behemoth of a blade or not..

Major hard use test last night at the county fair



^^ that was a pumpkin spice funnel cake and it was absolutely incredible.


The blade is starting to patina. I did my best to clean the blade off after cutting it and I managed to get some sugar and sauce into the pivot even despite how long the blade is, which is yet another reason I don't like to use short blades. I did put some Tuf-Glide into the pivot when I first got it so we'll see how that goes.

this thread is evidence of why we need to be able to "like" threads and comments.

pumpkin spice funnel cake sound amazing, btw.

skeeg11 wrote: ↑

Fri Oct 01, 2021 3:30 pm

Will be really interesting to see how it holds up to one of David's torture tests. Chips in K390 are no bueno. Serration patterns may be regional or dependent upon steel selection, but I gotta say that I'm very impressed with the factory teeth on my serrated UKPK Salt.

I am honestly concerned about chipping. This is also my first experience with K390 so it's all around new ground, and judging by how slowly it grinds I have a feeling it'll be a nightmare to fix chips. I don't know if I have the courage to cut up that coax cable with this one


I'm also convinced there's something different about the serrations on this knife and I think it has everything to do with the steel. Even though that Police OG I compared it to is an "old model" it IS a current production knife, it's not old stock from 20 years ago, it was bought just last year and can't be older than a couple years since it was made, so the serrations pattern is just as up to date as anything else Seki is making, and the patterns on the two knives are definitely different. It may just be that a more coarse grinding wheel had to be made to cut this steel or something, but the CNC-ish looking lines in on the bevel have me wondering if it was really ground by a wheel or if they've started using a robotic arm to cut the bevel like they do with plain edge, because I've seen similar grind marks on plain edge bevels.

wouldn't those grind lines add to the toothiness of the edge? seems like micro serrations.

ladybug93 wrote: ↑

Sat Oct 02, 2021 7:19 am

wouldn't those grind lines add to the toothiness of the edge? seems like micro serrations.

You are correct. Which means potentially this knife may perform better with the factory edge than any time after sharpening it, if those micro serrations add to cutting performance.







Even the plain edge at the tip has some of those same grind lines.



Also moving right along with reprofiling it. Diamond rods are doing just fine. I also found that a micro fiber towel does a great job of cleaning out the metal dust from diamond/CBN rods as you work. They load up fast. I'm taking it extra slow, I don't even wanna see what a nightmare a burr can turn into with this steel and serrations.

I also plan to stop reprofiling before I make it all the way to the apex, I still wanna see how that factory edge performs and get an idea of what edge retention is like and even how prone it may be to chips.


Also, I was initially not super impressed with how sharp this knife was. It won't push cut phone book paper, but it feels really sharp to the touch. I'm thinking that probably has something to do with those micro serrations. I'll get some boxes and stuff together and cut some stuff up today and see how it goes.

I think it would also be reasonable to assume the serration grinding wheel would be of different materials for different steels. VG10 is considerably easier to grind that K390, and the wheel required for K390 would be much more expensive. I’d love to see how the wheels are made. Is it a disk or wide cylinder? A monolithic piece, or a series of thin diamond faced discs stacked to yield the serration pattern? That construction would give the grind striations in the serrations.

Not to take away from the glory of this knife but I had to compare it to my Caribbean, and it just makes me that much more impressed with the Caribbean design and I fear I'll forever be a Caribbean fanboy. I've had it in my head this whole time that the Police 4 would be the reigning King of SE folders because it seemed so huge but the cutting edge is only about 3/8 shorter than the Caribbean and most of that difference is in the plain edge tip, there's pretty much the same amount of serrations, though there are more individual serrations on the P4 due to the scallops being shorter in length.





The Caribbean also packs all that edge into a more compact package while still having a roomy handle. It's really an amazing design. I think the only knife that will eventually dethrone the Caribbean may be the Cliff Jumper/Sequoia.