Battle of the Navy Seals : Part I

[Cliff Stamp]

Blade geometry and NIB sharpness :

The SOG SEAL is 1/4" thick 440A at 56-58 RC, 1.25" wide and 345 g. It has a sabre-flat primary grind ground at ten degrees per side. The tip has a distal taper of 2.8 degrees per side and the dual grind nature presents a slim profile. The edge ranges from 0.047" to 0.55" thick behind the bevel which is ground at 26 +/- 1 degrees. The serrations are chisel ground at about 20 degrees included.

NIB primary edge :

On thread => 275 +/- 34 g
1/4" poly 1000 g load => can't make a cut
1/4" poly 1500 g load => 1.62 +/- 0.09 cm

The blade only shaves smoothly near the tip. Using just blade weight the primary edge just scores the poly after 50 passes back and forth. The serrations are more aggressive and cut through the poly only needing 10 passes. The serrations are very rough showing multiple 0.1-0.2 mm areas of damage under magnification, they look ground by not polished, they just bust the thread (650 - 750 g).

The MPK-TI is also 1/4" but being TI is much lighter at only 250 g. The primary grind is full flat and only 3.5 +/- 0.3 degrees per side . The edge ranges from 0.030" to 0.032" thick behind the bevel which is ground at 20 +/- 1 degrees per side. The serrations are chisel ground at approximately 15 degrees included.

NIB primary edge :

Thread => 200 +/- 14 g
1/4" poly 1000 g load => 2.15 +/- 0.27 cm

Serrations :

Thread => 305 +/- 6

The serrations are much less finished than the plain edge and under magnification irregularities are visible similar to what is seen on the SOG, however they are larger, from 0.2 to 0.3 mm deep. The serrations can't be pulled across the poly when it is under 1000 g of tension. If I attempt to pull the blade it just digs in and then violently rips the cord suddenly.

In short, NIB, the MPK-Ti is much sharper. The SOG-SEAL looks to be over buffed the same condition as the Recondo I had in BG-42.

http://www.physics.mun.ca/~sstamp/knives/recondo.html

Cutting ability :

Push cutting on 3/8" hard poly, rocking cut :

SOG SEAL = 77 +/- 6 lbs
MPK-TI = 51 +/- 3

THe SOG require a much larger force showing its lower cutting ability. With the MPK given a rank of 100, the SOG would be 65 +/- 3. This greater performance of the MPK is mainly due to both a higher primary grind (full flat vs partial height flat), and a thinner and more acutely ground edge bevel, plus a more enhanced belly.

Chopping ability (two fingered snap) :

MPK-Ti / SOG Seal : 85 +/- 9

Neither blade chops well as both are close to neutral balanced. Chopping has to be done by snap cutting with a partial grip around the end of the handle. The performance of the knives is very close, the difference that I saw was just noticeable. More chopping would I am sure have refined the relative performance of the SOG, it is under the MPK, but just barely so. However, considering the MPK-TI is 260 g and the SOG 345, the chopping performance to weight ratio is horrible for the SOG SEAL. You are carrying around a lot more weight, but it offers no significant advantage for chopping ability because the performance is gutted due to the thick grinds. If the weight ratio is normalized the performance ratio becomes :

MPK-Ti / SOG Seal : 64 +/- 7

The MPK-TI is shown to be a much more efficient chopper per weight (about 50%), which you would expect given the higher performance cutting profile. This rank also reflects well the rope cutting performance which you would expect when the mass difference has been removed as they are both just push cuts through semi-elastic material.

Edge retention :

Primary edge :

Both blades were ran through cutting trials on 3/8" hemp rope . The cuts were slices made over 2 inches of edge. Four trials were ran with each blade, including a fresh sharpening which ended with a 600 grit DMT rod. The results of the four trials were them combined. In short, after fourteen cuts of the rope both edges had degraded to the point where they would not slice paper (more details will be in the respective reviews). However it should be noted that due to the much higher cutting ability of the MPK you ocld cut more rope at a specific leve of force. The MPK started needing 32-34 lbs and finished at 41-42 lbs. The SOG started at 41-42 lbs and at the end needed more than 50 lbs. Both sharpened with equal speed, the Ti blade tended however to gum up the hones.

Serrations :

The MPK has 2" of waved serrations and started off only needing 16-18 lbs to cut through the 3/8" hemp. After 254 cuts the performance had only decreased to the point that the blade now took 18-21 lbs to cut through the hemp. This is just at the point where I could tell that it had increased. I then did another 256 cuts through used and dirty 3/8" poly. This finally blunted the blade so it took 31-33 lbs to cut through the hemp. Checking the edge under magnification, only the tops of the serrations are worn and folded over. They protected the scalloped edges which do most of the cutting from grinding through the dirt left behind on the cutting block from the used poly. A few passes on a grooved steel and the serrations are back to cutting the hemp with 21-23 lbs.

Testing the serration pattern of the SOG revealed another matter. It has 1.5" of serrations which are pointier and more shallow. With over 55 lbs of force applied I could not get a clean cut through the 3/8" hemp, it is simply too difficult to pull the serrations through the rope, you basically have to bust it apart. The biggest problem is the cutting block under the rope, you have to drive the points in far too deep to allow the scallops to contact the rope. Walking on the rope and cutting it under tension, the MPK would outperform the SOG about four times to one in regards to the number of passes required under heavy force. The MPK would constantly cut through the poly in less than 1" or serrations while the SOG would require ~4 complete passes.

I then tested the serrations on many types of fabric, old jackets, jeans, sweat shirts, as well as various belts and webbing. The MPK would constantly outperform the SOG many times to one. The only material that I found that the SOG would cut well was something that weak that it would be readily torn apart. Cutting up some rubber tubing the SOG had an advantage over the MPK, about 25%. On wood, the SOG bites in a little deeper, but the MPK requires less force to be pushed through, neither had a
significant advantage as a wood saw.

Edge durability :

Both primary edges were durable enough to split 1-2 year old knotty seasoned pine and spruce. The force of the impacts was that large that the baton (a 2" piece of spruce) would be destroyed every few pieces of wood split.

Point penetration and durability :

Phone book, vertical stab :

MPK_TI = 656 +/- 27 pages
SOG SEAL = 707 +/- 7 pages

The SEAL was comfortable in the stab and penetrated well. The MPK had penetration very close to the SOG but suffered from a too square upper guard. Without enough radius, the pressure was high and thus not comfortable causing me to back off a little on the power of the stabs which skewed the performance. I was actually holding the SOG handle completely inside my grip for maximum power. Thus SEAL outperformed the MPK in this aspect both in regards to raw penetration (~10%) and comfort (significantly). However if you look at the penetration from a mass point of view, the MPK again easily jumps ahead of the SOG. The results scaled by mass :

MPK-TI = 2.6 pages per gram
SOG SEAL = 1.9 pages per gram

This has the SEAL at 71% of the performance of the MPK-Ti.

Doing some light prying it is obvious that the SOG is stiffer than the MPK-Ti, the critical question is what is the behavior under high loads? To investigate this, as well look at some other aspects I dug holes in 2x4's large enough to fit my index and middle finger through. The board would be dug half way through, flipped over and completed. The stabs would be hard getting 1/2"+ penetration, and the prying to the side at done with maximum force. Both the time it took to make the cuts as well as the number of stabs needed was recorded. The results :

MPK-TI = 39 +/- 13 stabs over 4.1 +/- 1.6 minutes
SOG SEAL = 46 +/- 5 stabs over 3.8 +/- 0.7 minutes

Three trials were run with the MPK, only two with the SOG, both tips had suffered visible damage. The tip of the SOG suffered a bend of about 5 degrees running back 1.2 cm. In addition the very last mm of tip was bent over 45 degrees to the side. The MPK suffered a smaller bend, under 3 degrees running back about 2 cm. Both major bends were corrected with prying in the reverse direction. The large bend in the extreme of the SOG tip had to be filed off.

In regards to the results, it is hard to judge digging performance off of them because so little work was done and the wood can vary tremendously. However from the feel of the stabs, I can say that the MPK's point gave better leverage as the SOG's tended to pop out more because of its diamond-like cross section. The MPK proved more durable taking less damage over more work.

Handle ergonomics and security :

The SOG is square, slippery where smooth and aggressive when checkered. Nothing great in the ergonomics or security department, however I had no real problems with the above work. The MPK has a nice texture, not slippery but not abrasive, the grooves help as well. The shape is a huge improvement over the SOG. The only problems are the lack of a radius in a few key areas.

Left to do :

-Handle security and ergonomics when wet/soaped
-handle durability
-edge durability under hard impacts
-corrosion testing
-edge testing which a re-profiled edge
-prying
-misc

Suggestions welcomed.

A picture :

http://www.physics.mun.ca/~sstamp/images/seal_2000_MPK_Ti.jpg

Note the SOG's serrations are ground on the wrong side for a right handed person.

-Cliff

 

[bensano]

Cliff

You are SO NEGATIVE.

The SOG's serrations are on the right side for a left handed person.

(Like me)

Ben

 

[Leemah1]

Cliff,

Thanks for an excellent review. Lots of great info.
For us poor schmoes, how about a price versus performance ratio.

Mission MPK = $350.00
SOG Seal 2000 = $108.00

Cheers,
Gord

 

[Cliff Stamp]

Ben, they still make left handed people ?

By the way, as an interesting note, I did see the effect formation of the Ti oxide layer after sharpening. I could get it to the level of blistering sharpness where it pops hairs (1200 DMT + fine ceramic), but it would degrade down to a shaving level almost immediately. Note that the oxidation rate is *not* linear, what forms in seconds is the practical limit.

Both blades could also be sharpened on a file, and both would cut much more 3/8" hemp when left with this edge. For example the MPK-Ti starts off requiring 30-32 lbs on the hemp with the filed edge (bastard cut), is 36-38 after 14 cuts, 38-42 after 30 cuts and only 45-57 lbs after 62 cuts.

Gord, on a price based performance the cheaper knife always wins, because you can't expect a linear relationship between cost and performance. The cheaper the knife the more it will dominate. For example a $2 Spyderco knock-off on a performance vs price perspective is a better knife than the Sebenza (or any custom folder if you prefer).

The question of worth has to be answered by the consumer, the performance can be quantified by someone else to a certain degree, but it is based on the monetary freedom of the reader as to if the performance increase is worth the money.

-Cliff

 

[RH]

Cliff, how do you torque rate a knife as it's cutting rope?

 

[Cliff Stamp]

When I cut the 3/8" rope I do three tests of sharpness; cut light thread and measure the amount of force required; slice 1/4" poly under 1000 g of tension and measure the blade length required, and finally measure the amount of force required to cut the hemp as all the slicing is done on a scale.

The thread and poly cutting are done throughout the cutting. I cut so much hemp, take the last two readings for its force measurement and then do the thread and poly cutting for a sharpness test. I also do a shaving test and slice and push cut on a sheet of photocopy paper.

I stop the cutting once the poly cut takes 4+ cm of edge, at this point the thread is taking 400 +/- 25 g, and the force to cut the hemp is highly dependent on the blade geometry. At this stage the blade will not slice the photo copy paper nor do any manner of precise work.

The number of slices of the hemp inbetween the edge testing are taken as powers of two as blunting is logarithmic. So I do two slices and then test the edge, then 4, then 8, then 16 etc. .

The thread and poly sharpness tests are quite stable. However the amount of force required to cut the hemp is not quite as accurate and far less precise as it depends on the methods used so it scatters a little more. It is also easy to throw it off by pressing down with your off hand so some care needs to be taken.

More details on the edge retention will be given in the respective reviews including a full description of the rate at which the blades blunt.

-Cliff

 

[bandaidman]

Usually I skip over Cliff's reviews as they run the gamut from overearnest to just plain fanciful. However I must comment on this one.

Cliff attempts to provide a "scientific" review by his generous use of numbers, ratings, data ranges to impress the reader with the validity of his findings when quite frankly his methods and analysis have no statistical merit.

Any scientific study must start with a question and to his credit Cliff has done that with the title "the battle of the seal knives" which implies two different knives will be tested.(we will ignore the null hypothesis etc for knife reviews for simplicity sake)

The materials and methods must be explained and be reproducible. The study should also be relevant to the item at hand. He has fortunately avoided chopping concrete or digging holes in this study and at least in two parts of his "study" has tested something relevant to knives: cutting rope and chopping wood. I am unsure of the utility of poking holes in phone books or stabbing premade holes in wood but will leave that to the reader's discretion.

Cliff states that he used 1000g load in his rope test(sounds scientific doesn't it?) but his explanation on how he does this on a consistant and reproducible basis is lacking. The use of a scale might give a rough estimation but does not control for the variability of angle, force or the consistancy of the force. There are cleary machines that can do this but their expense would preclude their use by a hobbyist. If anyone thinks they can apply an exact 1kg load in exacty the same way over and over again they are kidding themselves. The same criticism can be made for all the tests (is it the same exact swing, stab, etc? For the test to be valid each should be the same)

A proper study should also include more than a single subject (ie more than 1 of each knife to be tested) but again that is probably beyond the average enthusiast but it still lessens the value of the results.

Don't get me wrong, it is just fine to try such tests and report them, just don't analyze the data in a way that implies they have any statistical meaning (ie 275 +/- 14 g, or this knife has 71% of the performance of the other).

One must also look at the author's bias. Cliff has had public battles with SOG on this very board and that should always be considered when he reviews a SOG product. Cliff also seems to be a Busse fanatic now and that should be considered if he reviews one of their blades.

So why am I writing all this? I hate junk science, I get enough of it in the medical literature and don't want people to think this is good "science"

I welcome reviews but do not want to see a company sullied by a seemingly "scientific" review when in fact it is not. Especially when the author has publically battled the company in the past




I will now reveal my biases

1. never owned a SOG or mission knife, don't plan on getting any
2. once owned a Busse knife, but traded it away as I did not have a use for it but it seemed to be well made
3. I like customs: especially by Mayo, Simonich, and Blackwood
4. Cliff's posts make me laugh

 

[Mike990]

You have a bunch of movie reviewers. You find one you like, and whose take on movies seems to match yours. Then you read his reviews to determine what to see. I like Cliff's reviews. We all know where Cliff is coming from. He likes to break stuff. We might not agree with his methods, but its better than saying " it cut like crap" or "it cut great" At least Cliff tries to perform the same test the same each time. Cliff does as good a job as anyone else is doing sitting on their duff, writing in their impressions from doing nothing with the knife but looking at it. But in this comparison its apples and oranges, because the MPK-Ti can out pry the Seal knife by a great amount. In fact the MPK-Ti's ability to never have its edge rust off under any condition and pry
without breaking, put it in a class by itself for a very narrow range of uses. Mostly Saltwater diving. You should have seen what it took to break both Cliff. I understand nobody has broken a MPK-ti bare handed. Prying is what it does.

 

[Crayola]

My thoughs on the Stampinator:

Forst of all, bandaidman, I have never heard what equipment Cliff uses to test his knives, but I suspect that he uses soem gizmos that offer more reliability/repeatability than a locked hand and elbow grease. By a 1000g load, I bet Cliff means he clamps 1kg on the knife and pulls the knife across the medium to cut without adding top the load on the blade. Yes, load placement would make a difference in the experiemtn, but I suspect Cliff has some idea/formula worked out to eliminate variation as much as possible. Goddard has built some simple machines as well to test knives. Mike Turber used to clamp knives to a tool (I forget... a square? A miter gauge? Something liek that) so that he could keep the same angle on all knives used, and the same spot on all knive sused while doing cardboard cutting tests. With the blade clamped in, the gauge is laid on the cardboard and Mike pulls the knife. The same spot is used over and over again, so this is a good way to test edge holding.

About the numbers: I'm not sure if it is accurate to call Cliff's testing Pseudo-Science at all (which, Mr. bandaidman, you never did), but you ahev to take the numbers with a grain of salt. By that, I mean this. You have to keep in mind that Cliff's tests use one knife as a sample, so don't take the numbers as concrete, you know? Also, what the numbers BEST do for us the reader is offer comaprisons as far as ranking goes. Never mind that knife x chops to 71% the effectiveness of knife y. If you look at the numbers, though, you can say that under a certain load, you can take less swings with a Busse battle mistress than you will need to do with a Strider WB. A thinned out Lynn Criffith will outcut a Battle Mistress on light stuff (ignoring edge length differences), and so on. You get an idea of the relative performance of each knife, and that is all.

I bet there is LOTS left out of Cliff's tests that he can't write on. How many of us know how much force they are using on their blades? I dunno. Also, performance may be affected on the blades by sharpening ability. For example, I bet a knife made of S30V would severely outperform a knife made of AUS-8 or 440-C in a Stampinato test. But, suppose I can't sharpen S30V but 440-C poses no difficulty for me. The 40-C would probably be a better buy for me.

I think what Mr. bandaidman is telling us (please correct me if I am wrong) is that we musn't take the numbers as concrete proof that knife x is better than knife y. They give us a good gauge of relative performance, as long as you know the limitations of the tests (like my sharpening ability example.)

Even with "real world" examples of qualified users you have to take things with a grain of salt. For example, Jeff Randall my say wilderness knife X is AWESOME, and I shouldn't take his words lightly given his experiences, but knife X may still not be right FOR ME, as Jeff Randall and I are different. That is why some use hatchets, some machetes, some bowies and some khukuris for camping chores!


By the way, Mr. bandaidman, are you one of them cloth bandaids, or a G.I. Joe bandaid? Just curious.

 

[bandaidman]

Well I am not satisfied with purely subjective results either, but do not assume that Cliff's are really objective. To me there is often an agenda behind his tests, if you look closely you will see what I mean.

He grossly overstates the significance of his results and to me that is worse than saying "this knife sucks."

Any decent study must be able to be duplicated by other individuals, I doubt Cliff's "gizmo" qualifies.

Crayola: as far as what kind of bandaid I am, I am neither cloth or GI Joe. I alternate between Bugs Bunny and the Tazmanian Devil!!!!!!!!

 

[Will Kwan]

Cliff,

Great knife comparison. I have not had a chance to get out and do much with my MPK-Ti. It makes a great kitchen knife though the blade is a bit thick for this application.

How did the non-serrated sections of the two knives compare NIB? Was the MPK-Ti able to shave NIB?

You mentioned that the Ti gummed up to abrasive more. Do you think this is due to more metal being metal being removed? Perhaps, Ti particles are just finer and penetrate the pores quicker? Perhaps, the Ti blade burred or folded quicker than the steel and the burr is removed. I have noticed the same thing.

I found your comments about the oxide layer growth interesting. The MPF I had was sharpened so that it was shaving sharp and left for two weeks. It still had the same level of sharpness after two weeks. As was not able to test the blade seconds after sharpening since I had to hand it over to my reluctant friend for the shaving test.

While off topic, could you comment on how Ti compares to Talonite?



Will

 

[Gator97]

Originally posted by bandaidman

Usually I skip over Cliff's reviews as they run the gamut from overearnest to just plain fanciful.
So you don't read those reviews, but you know he does wrong things there...

Cliff attempts to provide a "scientific" review by his generous use of numbers, ratings, data ranges to impress the reader with the validity of his findings when quite frankly his methods and analysis have no statistical merit.
If he wouldn't provide the numbers I'm sure you and few others would immediatelly note that Cliff's reviews have no value as there are no numbers, too vague etc. IMHO it's easier with numbers. At least to understand what was happening during his tests. What's better
50, 150 and 450 g force to cut a thread, or scary sharp, very sharp and not that sharp knife?

The study should also be relevant to the item at hand. He has fortunately avoided chopping concrete or digging holes in this study and at least in two parts of his "study" has tested something relevant to knives: cutting rope and chopping wood. I am unsure of the utility of poking holes in phone books or stabbing premade holes in wood but will leave that to the reader's discretion.
As of the poking, considering that both knives are intended for Seals... I'd assume that given the situation operator may have to poke a hole or two, and the medium will varry. What do you suggest, next time for stabbing tests we get the enemy sentry to stab him, or something else relevant from the battlefield? What'd be the relevant test for the titanium Mission knife? To disarm a magnetic mine in UR bathtub?

There are cleary machines that can do this but their expense would preclude their use by a hobbyist.
I don't think machinery results apply to our real world. You can't replicate the machine, more likely you'll replicate another human than a machine.

...just don't analyze the data in a way that implies they have any statistical meaning (ie 275 +/- 14 g, or this knife has 71% of the performance of the other).
For that person, those 2 knives produced specific data. Your results may varry Mine too.
Make your own conclusions and if you want use his data as a reference. Positive or negative it's your business. And that's what he says always, even better, do your own testing.

 

[OwenM]

I thought this was supposed to be about a couple of knives, but it's starting to look like a review of Cliff's reviews

Dan,
I have to say that I have never seen Cliff battle a company. I have seen him post a negative review of a product that was not well-received, though. I have never seen him try to impress anyone with how great his reviews are, either, and he always seems open to criticism and input.
btw, Cliff is not a Busse fanatic. He is Jerry Busse, in case you didn't know, and sometimes Will York, as well. I thought everybody knew that

 

[Andrew Lynch]

Originally posted by bandaidman
I will now reveal my biases...
.........
4. Cliff's posts make me laugh

Well then, by your own rule, we should take that into account when reading your impressions of Cliff's reviews.

 

[Cliff Stamp]

bandaidman

The materials and methods must be explained and be reproducible.

Yes, this is why awhile ago I wrote up a description of the methods used for most of the things I do :

http://www.physics.mun.ca/~sstamp/knives/blade_testing.html

including problems that can happen and how to avoid them and get a stable result. The methods are far from final, and get refined as time passes some get radically altered. For awhile I was doing wood cutting on a specific type of hardwood dowel, for a specific length of cut and using the number of slices necessary as an indication of cutting performance. Over about two months I gathered data on more than a dozen knives. The first thing I verified was that the dowels were consistent. I bought several batches and used the same knife. It always tested the same to within a tight tolerance (<5%). As I continued I bought more dowels and would cut drawing from a random sample. The results came out consistent and I was getting some solid information on how geometry effected cutting performance and was able to do some rough modeling. However I ran into problems when I took it up after a three month break. I found that my strength increase meant that I could not compare new results to the old and there was a huge influenced on technique. Some knives could allow a very different method that would really skew the results out of proportion to the geometry. I am still trying to work all the bugs out. For example an Opinel can do the dowel cutting in 1.5 +/- 0.3 cuts. Now compare that to the results in the table. The Opinel can use a torquing technique that some of the other blades can't because the induced wrist strain causes too high a fatigue rate. It is interesting then to still compare the numbers, but they don't correlate to geometry as well as they once did because now the methods change. However it does represent the raw performance difference well, it is the cutting ability when both are used at their maximum for a short period of time.

The study should also be relevant to the item at hand.

I would as stated above include this as a portion of the reviews, but companies simply won't provide the design intentions. I would of course explore other aspects besides this because knowing why something doesn't work is just as valuable as why something does. For example I use a fillet blade as a light machete. It does poorly, however it does let me understand how a neutral balance effects the performance. You have to take a wider view. I have friends who are avid trout fisherman who like quality fillet blades - but at the same time they must be able to handle the other type of utility work which can include cutting light poles etc. . For them this is part of a "good" fillet blade. It comes back to the point you made about stating a purpose. As I have clarified in the past, I don't do this specifically as I want the reader to do it. I have no desire to become promotional, buy this or don't buy that. I do work (the vast majority of which is what I am interested in) and the reader has to pick out what is important to them. Now my reviews do contain specific well defined goals, but the total picture (how the sub-classes are weighted) has to be performed by the reader. I was playing around earlier with some java-script which would allow someone to enter a weighting system and it would then compare the two knives. Assign for example a rating (1-10) for each sub-section and then a total weighted performance could be given. Something that I might spend more time on in the future.

He has fortunately avoided chopping concrete or digging holes

I didn't do the above simply because it can induce edge damage which would cause me to reprofile the blade and thus change the cutting performance, thus I do all cutting work first, then durability testing later. Specifically, the Mission MPK-Ti is promoted as being a solid choice over steel because of its ability to handle digging even in very sandy ground and to handle hard contacts (metals) which can damage steel knives especially in cold climates. There are specific references to this on Missions web pages.

... the utility of poking holes in phone books or stabbing premade holes in wood

Two of the requirements of the SOG SEAL 2000 design are "tip breaking strength", and "penetration performance".

the variability of angle, force or the consistancy of the force

Yes, there is random error in all experimental results however random error (or systematic) can be determined by doing repeated trials. For example, in regards to the rocking cuts through poly, while the speed and direction of force (as well of the makeup of the poly) all change from cut to cut, the mean is robust. For all of the above I do the standard tests of significance to see if the medians posted are actually different, with IQR / (1.075 * sqrt(n)) as the standard error of the medians if you are curious. I don't post up a lot of the statistical testing as I don't see a lot of demand for it. The raw data is available. I use median based statistics as they are more capable of handling outliers and are thus more robust.

Mike990 :

You should have seen what it took to break both Cliff. I understand nobody has broken a MPK-ti bare handed. Prying is what
it does.

It is interesting, I expected the MPK-Ti to be weak because of the RC, steel knives of that hardness are not overly durable. While it did take a set on the 2x4 digging, it did better than many steel knives of greater cross section. The points on the MPK's are very thin for hard use knives, I would be curious to see if a steel knife of that geometry could handle it any better.

Crayola :

... one knife as a sample

Yes, the results described in the above can vary perhaps even a lot if you get one of the knives which is significantly different from the one I had, however that doesn't speak well for the QC of that manufacturer. As I had only one blade I can't produce an independent estimate of the variation and thus estimate what is to be expected. However this is far from an insurmountable problem. Ask Mission or SOG about the QC procedures they have in place and thus a confidence estimate can be obtained. If they state that the knife I used was significantly different than the norm, as I have done in the past I would look at another sample if the one I had was deemed a reject.

performance may be affected on the blades by sharpening ability.

I had never considered that, but it is a valid point. Consider for example that the angle on the SEAL is greater than the largest angle on the Sharpmaker, whereas on the MPK is less. Anyone using the Sharpmaker would have problems getting the SEAL sharp, however the MPK would be with problem. I found both to respond well to both waterstones, ceramic and diamond hones. No real difference was seen besides the loading.

Will Kwan :

[MPK-Ti]

It makes a great kitchen knife though the blade is a bit thick for this application.

Yes, I have done comparisons of both in the kitchen, I didn't put it in the above as it wasn't a "SEAL" type use, which was what I was aiming for as sort of an entertaining distraction from some of the other more rigid work I have been doing lately. It is a refreshing change not to be concerned about a blade and to be able to leave it unattended even after cutting up acidic fruits.

How did the non-serrated sections of the two knives compare NIB? Was the MPK-Ti able to shave NIB?

The MPK-Ti was significantly sharper. The edge was lightly rolled NIB and thus would shave only on one side. It would slice photocopy paper held 1/4" from my grip but could not do a push cut. The edge was also rough showing irregularities from .05 to .025 mm deep, with a frequency of about 1 per mm. Stropping the Ti blade on CrO loaded leather (30 passes per side) caused a performance jump on the poly jumped down to 1.2 +/- 0.1 cm, a huge improvement. The thread level stayed the same. The shaving ability went up slightly, but the burr was still present. Based on some comments you made in the Mission forum on stropping I am going to spend some time seeing how the blade reacts in detail to this work.

[gumming]

Do you think this is due to more metal being metal being removed? Perhaps, Ti particles are just finer and penetrate the pores quicker? Perhaps, the Ti blade burred or folded quicker than the steel and the burr is removed.

I don't think it is the grain size because it doesn't happen with very fine steels like 52100. I think it is the actual structure which causes a smearing action.

The MPF I had was sharpened so that it was shaving sharp and left for two weeks. It still had the same level of sharpness after two weeks.

The difference takes place very quickly. From what I have read, the oxide layer forms "immediately", which I take to mean is a matter of seconds. The performance loss is not a constant rate, it goes from blistering popping sharp to shaving sharp and basically stays there. Specifically after 70 days the oxide layer is only 5 times as thick as it is immediately after the fresh Ti is exposed to the air.

While off topic, could you comment on how Ti compares to Talonite?

Similar in how they sharpen, they are both "gummy", both are of similar hardness and strength, I have found however that Ti is significantly more durable. If you are interested I have a Talonite blade that you can have a look at, it is out on loan to either Cougar Allen or Brian Thornburg. Just drop them an email and ask to have a look at it when they are finished with it. I'll cover shipping costs to you.

OwenM :

I have to say that I have never seen Cliff battle a company.

Damm man that was on pay per view last month for only $29.95! Cold Steel fought Busse Combat on the undercard.


-Cliff

 

[bruce]

1. Cliff's reviews are not all that scientific, but who cares? Most readers would have to have the science explained to them anyway.

2. We can always think of some test Cliff forgot, or another way to do something he did; but Cliff gives us a lot of performance to think about and compare to what we know as individuals.

3. Cliff has his preferrences, and "non-preferrences"; and so do I, and so do you. There isn't one completely objective person out there. ...and the scientific, objective world is quite boring to most people.

4. If you think you can do better than Cliff, have at it. I'll be glad to read what you come up with, and I bet Cliff will too. ...but I bet none of us will take the time!

Bruce Woodbury

 

[Jeff Clark]

I've been a certified knife-knut for over 40 years. I have owned and experimented with hundreds of knives. I've got a degree in physics and I've been an engineer for over 25 years. I am in awe of the sophistication and usefulness of Cliff's testing techniques.

Most experiments that I have tried or seen cover a narrow range of the uses of the knife and are low on quantitave data. Cliff tells you how the knife works new, how it wears, how it handles, how it sharpens and often how it breaks. I find that I can easily translate his numbers back into the practical and subjective arena. I learn something every time I read one of his tests.

 

[GREENJACKET]

Happy new year Cliff,
I've always liked the look of the SOGs; though I don't want one as I'm happy with what I'm using. (At one time the SOG Para Tool was the mulitool.) However, the comparison is most interesting and about what I would have expected. Nice to see it in print not just my flawed opinion (read wild guess). Price does make a difference and for the price the SOG is probably not such a bad buy. No knife is perfect and these results are not exactly earth shattering. Certainly nothing reported could be considered detrimental. Findings gave a few parameters. Both knives seemed reasonably high; well high enough to have no real bearing on the usefullness of the tool for use. Room for improvement; when isn't there. Cliff's comparison only shows differences as points of interest. Points that I find interesting.

 

[bandaidman]

Well, it has commented on that this post has become a review of Cliff's review and that was indeed my point.

Again, my post was made to point out the weaknesses of his study. Many here can pick up on them on their own. You can do what you want to with his posts, that is the reader's perogative, just recognize the limitations of his results and statistics.

It was asked of me why I would be critical of Cliff Stamp as he seems to be an earnest, well meaning fellow who simply wants to test some knives. Well, the answer to that is complex. Cliff was "difficult" to deal with for many people here in the past (one of the reasons he was removed as a moderator here as I recall, please correct me if I am in error) and to his credit he has toned down his rhetoric quite a bit. His primary interests appear to me to be destructive testing and blade angles. A small part of the total picture of knife performance but valid things to be interested in.

What prompted me to post in this thread were actually his posts in another thread (see S30V and Phil Wilson) where he posts at least 10 times about a steel he apparently has never held in his hand. He argues with people who are recognized knife authorities based on hearsay (his conversation with Mr. Wilson), reading crucible data sheets and I assume his prior experience with other steels.

This like me arguing about how a certain cereal tastes based on my reading of the ingredients with someone who has actually tried the stuff. The corollary would be "I have tasted other cereals, of course I know how this one will taste just by reading the box!"

Cliff (like another Cliff from "Cheers") comes off as a know it all, someone who is long on opinions and sometimes short on the facts.

While I do think Cliff does have worthwhile information to share the overall utilty of it all is limited by him overstating his results (and their significance) and forming strong opinions based on limited information. I applaud him for at least trying, my criticism is directed at his often over-enthusiastic opinions and results.

Caveat Emptor

 

[bandaidman]

before someone else says it (like my wife), I too am a "know it all", just on different stuff.....