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Spyderco Persistence - An Experiment in "Cheap" Steel

Posted by Steel_Drake 
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Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 01:25PM


So recently, while once again bemoaning the relative dearth of production folders in fine grained steels (where I would trust the heat treat), I stumbled across some posts by both Cliff and me2 about Spyderco's 8Cr13Mov being relatively fine-grained and run with a decent heat treat.

Given the relatively inexpensive prices on Spyderco's made using this blade steel, I decided, what the hell, I'll give it a shot. In any case I wanted a knife to practice significantly thinning out the geometry on before I started tackling my Aogami Super sprint runs (yes, yes, I'm a weaboo).

I looked at both this knife and the Tenacious, and I felt that the handle on the Persistence was a much better size for my hands than the larger Tenacious model. Fit and finish was pretty impressive for a "budget" line, with blade centering quite good and the grind fairly even. It was at least as good as most Spyderco models, regardless of price.

Since my earlier posts on this forum asking for sharpening advice, I've moved on a fair bit. I now use bench stones for edge bevels and use the Sharpmaker only for micro-bevels.

I took the Persistence to my DMT Extra Course and got to work convexing the primary grind down to the edge. It took me a while as I simply don't have the confidence to go at the kind of speeds someone more experienced would, but in the end the task was accomplished without too much frustration.

I then proceeded through the DMT Fine, Spyderco Medium, Fine, and Ultrafine benchstones, ultimately using my loaded balsa strop (which I've stopped using to actually strop) to polish the lower part of the bevel to something reasonably approximating a mirror finish. As the spine is about 3mm above the benchstone for the edge bevel, some simple math says the edge bevel is ~6 dps and 1mm broad, and the primary bevel behind it is now ~4.5 dps.

Finally, I micro-bevelled at 15dps with 5 pps on the sharpmaker using the medium, fine, ultra-fine, and oiled ultra-fine rods (I use a thin coat of mineral oil on the UFs to cut their effective grit).

The resulting edge was, by some margin, the sharpest I've ever produced on any knife I own. It would trivially pushcut newsprint against the grain at 90 degrees, tree-top hair, and will sink into any relatively soft material with less than the weight of the knife.

I found that impressive, but not nearly as impressive as I found the cutting performance with the thinned out geometry. Frankly, I was stunned at the leap in cutting performance compared to any other folding knife I've used. It's one thing to read Cliff and others contend that geometry dominates steel choice in cutting performance, it's quite another to experience how large a difference geometry makes.

I've been carrying the knife for a few days and have been fairly happy with it so far. The edge retention was not very good on the first apexing after the re-grind (either through overstressing when I reprofiled, or from the factory grind, who knows) but after the second sharpening the high-sharpness edge retention has been quite decent in my EDC uses (mainly cardboard, packaging, and kitchen prep). I also found that, as reprofiled, sharpening was both quick and easy to produce similarly sharp edges.

In terms of ergonomics, the handle fits me perfectly and the fairly high-traction G10, combined with the thumb-ramp, gimping, and downward curve of the front of the handle before the blade gave me a very secure feeling grip in my uses so far.

My main complaint about this knife would be the excessive strength of the closed detent using the ball bearing on the liner-lock. Having looked into it, it seems that I will have to find a way to round off the indent on the blade for the ball-bearing to ease it coming out of the closed position. Unfortunately I don't currently have access to any option better than the corner of a Spyderco diamond rod to accomplish this with, so I've been dallying on getting to it.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 03:57PM
To add a little to the above:

In kitchen use the knife performed very well as a paring knife. I found the ergonomics excellent both in a saber grip and a reverse grip, and really liked the larger curve to the tip on this knife compared to a paring knife for tasks like cubing garlic and finely slicing a hot pepper. In a reverse grip my index finger rests comfortably on the thumb-ramp giving my thumb easy access to push towards the flat of the blade. Additionally, the very high sharpness made light work out of any task I've put it to in the kitchen so far.

Also, I disassembled the knife to round the address the closed detent and found that a few minutes using the corner of a Syderco diamond rod to slightly round the edge of the detent hole in the blade in the area where the ball bearing meets it in the closed position was enough to ease the transition from closed to opening enough for my liking. I was concerned it would take a lot more rounding than I actually did to achieve this, so I was quite happy about that.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 04:09PM
I have often wondered could Spyderco make even a sprint run with that kind of geometry. The problem that looms of course is what happens when someone moves beyond the geometry hence why it is likely to stay in the regrind area.

However as more kitchen knife manufacturers are willing to make these blades then companies like Spyderco have to step up. It simply looks odd when a $5 kitchen knife has a thinner and lower angle edge than a $50 kitchen knife from Spyderco.

If people then try to use those $5 paring knives for utility work then real problems arise in regards to relative performance questions.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 05:48PM
Quote
Steel Drake
Frankly, I was stunned at the leap in cutting performance compared to any other folding knife I've used. It's one thing to read Cliff and others contend that geometry dominates steel choice in cutting performance, it's quite another toexperience how large a difference geometry makes. 

I couldn't agree more. This is how I felt after using the Herder paring knife for the first time, which is what prompted me to start thinning out some of my other knives. My $7 Kuhn Rikon paring knife now outperforms any of my Spyderco folders and my BK-15 cuts better than my South Fork, d'oh!

-Nate
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 05:55PM
Quote
CliffStamp
I have often wondered could Spyderco make even a sprint run with that kind of geometry. The problem that looms of course is what happens when someone moves beyond the geometry hence why it is likely to stay in the regrind area.

However as more kitchen knife manufacturers are willing to make these blades then companies like Spyderco have to step up. It simply looks odd when a $5 kitchen knife has a thinner and lower angle edge than a $50 kitchen knife from Spyderco.

If people then try to use those $5 paring knives for utility work then real problems arise in regards to relative performance questions.

Well, considering the problems with the early Nilakkas, wouldn't there be a high risk of over heating the steel by machine grinding? That alone would give rise to all sorts of warranty issues as most customers are likely to assume the knife is crap rather than sharpening it enough to get under the damaged steel.

Hell, the micro-bevel failed almost immediately after the first sharpening after I thinned down the geometry and that's with a DMT XC by hand, of course, as I frequent this place, I was aware it was probably my fault and that I would have to distress and re-apex to get under steel weakened by not being light enough on the DMT XC.

And that's even before getting into the potential issues that could result from people using a folder in a way they'd never use a kitchen knife. While you, specifically, can use a kitchen knife for hard cutting tasks, I assume there's a fair measure of skill and technique involved to avoid damage on thin geometries.

I also think your comment about kitchen knife makers ties into the comment I made about the effects of edge-bevel geometry on "cutting ability retention" that I mentioned in the carpet testing thread. Debating which steel is better in folding knives for edge retention while those blades are in ridiculously thick geometries is like debating what kind of tires to put on an armored personnel carrier before trying to use it as a race car: It totally misses the point.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 10:02PM
Nice work. You have me wanting to attempt this with a Tenacious when I get some more experience and stones. About how long would you say the major steps took with the DMTs?
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
October 31, 2014 10:40PM
Spyderco could offer the entire budget line with a ffg at a low angle (ie. +/- 6dps), jack up the price and give it a nifty name...

Spyderco Tenacious ULTRA-SHARP

They'd probably make more off of something like that than they would off of sprint runs. If you are willing to pay $45.00 for a Spyderco, you are probably willing to pay $55.00 for the "Ultra-Sharp" version.


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 01:05AM
Interesting thought, Chum. I had a somewhat similar idea. Spyderco sells knives from their factory outlet at full msrp. It might be cool if all the knives they sold direct had extra thin grinds and higher QC on the bevels... I have many more than I need at this point anyway, but if that option existed I would have paid the extra cash for a couple "extra high performance" models.

Steel Drake, can you estimate how mch force you use on your xc dmt plate? Just the weight of the blade? I haven't been happy with mine for grinding and ended up flipping it over and putting a sheet of wet 100 grit sandpaper on it. I thought this ground the 1095cv on my Becker much faster. I think a big part of this was that I was no longer afraid of using too much pressure.

-Nate
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 01:48AM
Quote
geometry
Nice work. You have me wanting to attempt this with a Tenacious when I get some more experience and stones. About how long would you say the major steps took with the DMTs?

I would say it took me a couple of hours on the extra course DMT. Keep in mind I don't go nearly as fast as someone more experienced, and I'm frequently stopping to check that I'm keeping the grind reasonably consistent. I'd say another hour to progress through the rest of the bench stones, but keep in mind that polishing the lower part of the thinned primary is an aesthetic choice, I could have gone through the rest of the stones in about 10 minutes if I'd only cared about the 1mm broad edge-bevel and apex before micro-beveling.

Quote
Apophis
Steel Drake, can you estimate how mch force you use on your xc dmt plate? Just the weight of the blade? I haven't been happy with mine for grinding and ended up flipping it over and putting a sheet of wet 100 grit sandpaper on it. I thought this ground the 1095cv on my Becker much faster. I think a big part of this was that I was no longer afraid of using too much pressure.

Basically, I'm trying to use about the weight of the knife. Once you start pressing down into the plate with more force than that, it really starts to dig into the blade. This makes keeping a consistent angle difficult, and leaves deep scratches that are time consuming to polish out later. I have no idea if it would be okay to use more pressure, you'd have to ask someone with more experience with DMT plates that, but for me I'd rather go slow and steady to get the results I want.

The nice thing is that on subsequent sharpenings where I'm re-apexing, it takes less than 10 minutes to work through the bench stones because the edge bevel is only about 1mm broad.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 02:29AM
Quote
Chum
Spyderco could offer the entire budget line with a ffg at a low angle (ie. +/- 6dps), jack up the price and give it a nifty name...

Spyderco Tenacious ULTRA-SHARP

They'd probably make more off of something like that than they would off of sprint runs. If you are willing to pay $45.00 for a Spyderco, you are probably willing to pay $55.00 for the "Ultra-Sharp" version.
That would be a highly interesting experiment. With a clear policy on them and next to no warranty against breakage it might not be an unmanagable PITA for Spyderco, especially on the low cost models. Though if they cut better than the rest of the company's line up it could present some dilemmas for the "super steel" fanatics and possibly an undesirable position for Spyderco.

There seem to be quite a few people paying a much higher premium for regrinds. I'd be happy to pay extra for better edges over high cost materials for the most part.

Quote
Steel_Drake
I would say it took me a couple of hours on the extra course DMT. Keep in mind I don't go nearly as fast as someone more experienced, and I'm frequently stopping to check that I'm keeping the grind reasonably consistent. I'd say another hour to progress through the rest of the bench stones, but keep in mind that polishing the lower part of the thinned primary is an aesthetic choice, I could have gone through the rest of the stones in about 10 minutes if I'd only cared about the 1mm broad edge-bevel and apex before micro-beveling.
Thanks, that sounds reasonable especially since you were using only the weight of the knife.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 03:26AM
Its good to know the time you spent on it. My experience on the XC sounds similar, didn't have the patience for it. I've been grinding pretty flat and don't care about the finish, wanted something faster.

The Persistence is a nice little knife. The blue one started me down the Spyderco rabbit hole. Steels aside, I'm still amazed the variety in their lineup. The Chaparral is the only one of mine that I've mangled the finish on so far. It's the one I use and carry the most. Still have more work to do it.

-Nate
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 03:34PM
Quote
Apophis
Its good to know the time you spent on it. My experience on the XC sounds similar, didn't have the patience for it. I've been grinding pretty flat and don't care about the finish, wanted something faster.

To be honest, I probably could have gotten through it quite a bit faster, but I was really taking my time to try and minimize the chance of screwing up. The last thing I wanted to deal with was an uneven grind (i.e. uneven across the same side) or a rising tip.

One thing that I feel is key with thinning out the geometry is to start with your finger pressure on the shoulder of the transition from the primary bevel to the edge-bevel and work from there. Some other experience with re-profiling indicates that the most inefficient way of doing it is to lay the primary flat onto the stone and work down to the edge. Instead, I started on the shoulder and convexed up to the primary and down to the edge. This means it's not a FFG down to to the edge bevel yet, but that can be addressed in smaller bites on subsequent sharpening.

Quote

The Persistence is a nice little knife. The blue one started me down the Spyderco rabbit hole. Steels aside, I'm still amazed the variety in their lineup. The Chaparral is the only one of mine that I've mangled the finish on so far. It's the one I use and carry the most. Still have more work to do it.

I'm really impressed with the ergonomics of the knife. Frankly I like the ergos quite a bit better than my Delica SB, and on par with my Caly 3 SB. Now, I still expect the Delica to end up the best performer of the bunch when I get to reprofiling it (higher hardness, finer and more even grain on the SB, thinner blade stock, less height in the blade), but as far as ergos go, the Persistence is right up there.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 04:16PM
Quote
Steel_Drake
To be honest, I probably could have gotten through it quite a bit faster, but I was really taking my time to try and minimize the chance of screwing up. The last thing I wanted to deal with was an uneven grind (i.e. uneven across the same side) or a rising tip.

One thing that I feel is key with thinning out the geometry is to start with your finger pressure on the shoulder of the transition from the primary bevel to the edge-bevel and work from there. Some other experience with re-profiling indicates that the most inefficient way of doing it is to lay the primary flat onto the stone and work down to the edge. Instead, I started on the shoulder and convexed up to the primary and down to the edge. This means it's not a FFG down to to the edge bevel yet, but that can be addressed in smaller bites on subsequent sharpening.

Yes, this is all in-line with how I started. On the Chaparral I put in roughly 500pps on the XC going slow and trying to stay right on the shoulder. But I just lost patience with it that way and eventually started grinding at a much higher speed (multiple passes per second). I drop my angle when I speed up to try and compensate for the extra slop so I don't gouge or round the actual edge. I am still mainly working on the shoulder/transition area and leaving a light convex though.

I need to give my Persistence some time in the rotation. I just happened to find a good deal on the Chaparral a few weeks after I got it and hasn't gotten a fair shake since.

-Nate



Edited 1 time(s). Last edit at 11/01/2014 04:20PM by Apophis.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 01, 2014 06:09PM
Steel Drake... I like the design of the of the Persistense (and all the budget Spydercos) quite a bit. The one thing I don't "think" I care for is the possibility of guillotining my finger if the lock fails. On my Delica there is that flat choil area that will hit my finger if the blade closes on it.

With the knife as sharp as you have made it, is that a concern with you?





Quote
geometry
That would be a highly interesting experiment

Spyderco could also give them a specific color for the handle slabs. Give the Ultra-Sharp series deep-red handle slabs (or something like that.)






Quote
Apophis
Spyderco sells knives from their factory outlet at full msrp. It might be cool if all the knives they sold direct had extra thin grinds and higher QC on the bevels

I like this idea as well.


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 02, 2014 02:27PM
Chum, it's not apparent when open but the Persistence has an unsharpened area which I really like for safety when closing.





Edited 1 time(s). Last edit at 11/02/2014 02:28PM by jumbo.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 02, 2014 03:16PM
Quote
jumbo
Chum, it's not apparent when open but the Persistence has an unsharpened area which I really like for safety when closing.


I really like how they managed to keep the unsharpened like the Delica, without it placing the blade farther from the end of the handle actually. I think it's a neat solution where there isn't a finger choil.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 02, 2014 08:40PM
Thanks jumbo, I didn't realize that's how the Tenacious/Persistence was designed. Very nice!


Chumgeyser on Youtube
E-nep throwing Brotherhood. Charter Member
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 03, 2014 08:43PM
The Tenacious is one of my most used folders in the last year or so...from electrical work to the kitchen...
I will do a cast blade for mine when I get the time and money...just for a look-see how it does...
The handle is quite comfortable for me too...
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 04, 2014 10:55PM
Just a little update:

I bought a set of calipers today and measured my Persistence at the transition to the edge-bevel and at 1mm from the edge. It averaged ~0.010" at 1mm from the edge, and ~0.007" at the transition to the edge-bevel. It also had no trouble slicing through the clam-shell packaging the calipers came in.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 05, 2014 10:56PM
I wonder if the same results could be obtained with an Enlan knife?
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 06, 2014 02:17AM
Sure you could, there's no reason it couldn't be done. I've brought an Enlan down to 10 dps and thinned the primary a bit. There's no reason why I couldn't have just brought it to a true zero.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 06, 2014 06:58PM
I would think the relevant question is whether the heat treating and quality control thereof would be of a sufficient standard for the 8Cr13Mov to be able to handle being run in a similar geometry. I have no basis to know, personally, but hell, at those prices it's certainly worth a shot.

After doing quite a bit of mucking around with sharpening trying to confirm what Cliff suggested was the reason I was getting finer push-cutting edges by micro-beveling with a M/F/UF progression rather than UF alone, I have also noted that while the 8Cr13Mov in this knife will take a very fine push-cutting edge (smoothly push cutting an entire page of newsprint across the grain at 90 degrees, etc.), it requires a fair bit more care and attention to achieve such an edge than it does with my Aogami Super Spydercos.

At some point I'll have to do some fairly unscientific testing to see whether high sharpness edge retention differs perceptibly.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 07, 2014 12:09AM
Quote
jwolf83
Sure you could, there's no reason it couldn't be done. I've brought an Enlan down to 10 dps and thinned the primary a bit. There's no reason why I couldn't have just brought it to a true zero.

Are you sure about the Enlans? Cos I have 3 of them in 8Cr13MoV ( EL-02,EL-04 and L05-1 ) with a progressive relief of 5 - 7,5 - 10 - 12,5 and 15 DPS with micro bevel at 20 DPS; the edge doesn't support a fine edge like my Byrd Cara-Cara ( China Spyderco ) with 15 DPS micro bevel.

The edge feels exactly like a D-2 steel ou a CPM-S30V with little usage; and this is right after the spyderco fine stone. Is a toothy edge, although no further microchips are found in tasks like cardboard or wood.

The 9Cr13MoV in EL-08 edge is quite better, although the blade is optimized for heavy tasks.

A photo of EL-04 converted in FFG ( same was done on EL-02 ):

Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 07, 2014 01:28AM
If you are having edge retention issues on one knife and you have another knife that is in the same steel then I would suspect that either the heat treat was bad OR (and more likely) they burnt the edge at the factory final sharpening. You will have to remove the damaged steel to get to the true 'good' steel beneath. Looking back, I realize this happened to me with a Manix XL I had in s30v. It would begin blunting after cutting one simple thing after sharpening!! this is not normal behavior and s30v is a good steel with good edge retention characteristics.

anyway, keep us posted. Nice regrind btw!
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 07, 2014 02:54AM
I'm not claiming that it would hold that geometry well or that Enlan is heat treated to the standards of Spyderco but I do know my El 01 in what's claimed to be 8cr13mov can hold 10 + or - 1. Nice regrinds on those Enlan's Cabraljr.
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 07, 2014 10:59AM
Thanks guys!

Clarifying the Enlans edges: they were sharpened several times after the regrind, that was carefully done with constantly water cooling and never to the apex itself ( I use de 20 DPS microvebel as visual guide, cos I always make a relief and microbel in my stock blades ). And the L05-1 that is from factory FFG ( but have plenty of room for a relief before microbeveled and both are always made in bench stones and sharpmaker ) has the same edge behavior ( toothy ).

And yes, I follow the Cliff 3 steps in sharpening, cutting the edge perpendicular to the stone to eliminate stressed steel.

It doesn't seems to be a grain growth issue do the blades shown a decent toughness. Perhaps insufficient temperature soaking and large primary chromium carbides left behind, I don't know.

Definitely not the same behavior as the Spyderco/Byrd 8Cr13MoV that I have.

Please, forgive my terrible english. I can read quite well but my grammar and writing are awful!
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 07, 2014 08:24PM
No need to say sorry...
You are perfectly clear...drinking smiley
DK
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
November 28, 2014 01:54AM
i love that reground enlan

"knives save lives" on youtube
all i want for christmas is more arm hair -DK-
Re: Spyderco Persistence - An Experiment in "Cheap" Steel
December 02, 2014 06:35PM
I found out the same thing with the Benchmade 940, it was the sharpest out of the box knife I have ever had, and I bought it at a pawn shop, and still haven't touched up the edge, many years (10+) and it still cuts like crazy. Go figure!