ParaMilitary - A Sharpening Tale

[JDEE]

I was down the paddock out at the farm on Saturday before opening the shop when I came across a patch of "Pattersons Curse" (a noxious weed proscribed by the government and if you don't get rid of it a pretty hefty fine) and as I didn't have much time to go back for the hoe I decided to use my ParaMilitary which was in its normal sharp-sharp condition. Our soil is pretty gritty with clay and lots of rocks so it was with some trepidation that I got down on my knees to dig out a patch about 2 metres square. With the "Curse" you have to dig it out not cut it off. Anyway by the end of the session I had an edge "you could have ridden to London and back on" - basically rounded with very little chipping. When I got around to putting the edge back late last night I thought I would be busy for a while - not so. Firstly, I put it on a coarse stone at 30 degrees until I achieved a "burr" and proceeded to the coarse rods on the Sharpmaker at 30 degrees. In less then 20 minutes I had a pristine sharp-sharp edge certainly a testement to the Shapmaker, the ParaMilitary's toughness and blade profile and to the S30V steel. It wouldn't have mattered what steel it was it would have had chipping but there were only a couple of minute ones after my destructive work. I am sure many a lesser blade would have ended up in a lot worser condition than the PM.

[skcusloa]

So you got the chips out of the blade in 20 minutes? I've spent over 2 hrs on my military and I had 2 sets of freshly washed brown stones and the chip was still there. I finally got it out of there today. All I did was run my edge into a staple.

I didn't spend 2 hours straight. That's over time. Probably about 3 hours straight.

[Magic]

It wouldn't have mattered what steel it was it would have had chipping but there were only a couple of minute ones after my destructive work.

Maybe you could find some more of the identical plant, and use a vg-10 knife. It would be interesting to see if it also chips....you can say that it doesn't matter what steel it is, but I'll tell you that you read about chipping of s30v much more than you read about chipping with vg10 on these forums and at bladeforums.

In fact, I don't remember reading about vg-10 chipping at all....although I'm sure it could in the right circumstances...

[JDEE]

Skcusloa I think you will find it was a completely different situation. Your chips I presume are in a sharp edge mine were in a blunt edge and I do mean blunt so blunt I had to resort to the coarse diamond stone to repair the edge before I got out the Sharpmaker. There is no way I would have attempted to restore the edge with only the Sharpmaker. I sympathise with you removing chips from a sharp edge is not easy.

Magic It was not my intention to buy into the S30V chipping arguement which has been dealt with over and over on all forums I was merely saying that a much lesser steel would have been worse off and I can assure you I don't intend doing it again unless it is unavoidable. I only have a Delica in VG10 and I don't intend sticking it in the type of soil I did because it wont stand up to it - it is a different blade all together. I doesn't matter what plant either it was that you had to dig down up to 2" in some instances to remove it and a lesser steel and a lesser knife would not have held up as well as the PM. IMO as far as the worth of a blade goes it is not only the steel used but the heat treatment and the blade profile that determine how good a blade is. Too much emphasis is put on the steel and not enough on the profile of the blade. This is where the PM excells it has about one of the best profiles I've seen on a folder which not only ensures that it has good cutting endurance and slices well but also that you are able to bring the blade back so quickly without having to extensively reprofile the blade.

[skcusloa]

I found out how to get the chip out of there much faster. I found some cheap diamond stones at harbor freight. I rubber banded them to the sharpmaker. Took like 5 minutes to completly regrind the blade. Strange thing is near the rear of the knife it didn't regrind the whole factory bevel, it's like the factory bevel was steeper than 30 degrees or something. Oh well, it's still incredibly sharp there. Shows the sharpmaker without the expensive diamond rods is for maintaining a super sharp edge not creating one.

Now I have to do all of my really dull kitchen knives too :)

I think the sharpmaker should come with diamond and white stones.

[Phalanx7.62]

Then it would cost $150 and people would just buy the edgepro.

I use a Gatco Diamond kit (similar to the Lansky) for all rough reprofiling, then I finish/touch up with the Sharpmaker and a leather strop with Vertias green.

Diamonds do cut super-fast. I can't imagine anyone doing any serious reprofiling with the sharpmaker. Those browns are just not coarse enough to cut that much. Diamonds would be needed there.

[David Lowry]

In fact, I don't remember reading about vg-10 chipping at all....although I'm sure it could in the right circumstances...

I've had the points of the serrations on my VG-10 Delica chip off. This happened with just normal use about 2 weeks after I got it. Wasn't real happy about it but it's a knife. It gets used.....I can live with it :)



Too much emphasis is put on the steel and not enough on the profile of the blade. This is where the PM excells it has about one of the best profiles I've seen on a folder which not only ensures that it has good cutting endurance and slices well but also that you are able to bring the blade back so quickly without having to extensively reprofile the blade.

Very good point that I often forget to think about. ;)

[HoB]

is not only the steel used but the heat treatment and the blade profile that determine how good a blade is. Too much emphasis is put on the steel and not enough on the profile of the blade.

Amen to that.

[mikemck]

Why not just avoid the damage in the first place by digging with the back of the blade? That's what I do, and I don't have a dull or chipped edge when I'm done.
I mean really, it does not take a knife edge to cut dirt, if you see what I mean.

There are many many uses for the back of the blade, as long as it's not chamfered or rounded, like the Caly Jr. or, say, a Sebenza :D

[ghostrider]

IMO as far as the worth of a blade goes it is not only the steel used but the heat treatment and the blade profile that determine how good a blade is.That is so true. One of the reasons I liked the Kershaw Whirlwind (440A) so much is that it took, and held an edge very well. Not as good as VG-10, or possibly some other steels, but definitely as good, or sometimes even better than some of my AUS-8 knives. Another good example it the Buck 110 hunter, which uses 420HC. I once used mine to clean, skin, and butcher 2 ½ deer with before it stopped shaving hair off my arm. I’ve always thought that the grind, heat treat, and tempering of the blade had a significant effect on the performance of the edge.

BTW: Magic,

I had a VG-10 blade with chips in it. I didn’t use it for anything other than cardboard, and once nylon rope. In truth, I didn’t sharpen the thing until it started snagging on the cardboard, so I basically didn’t properly maintain the edge.

I have no experience with S30V, but I didn’t think it seemed to be a problem around this forum. It’s difficult to determine if particular steel has problems with chipping when one doesn’t have the opportunity to view the edge before and after the chipping occurred. Often times, the performance of the edge can be traced to the maintenance of that edge. IMO, there are two ways in which a knife “dulls”. The edge either “rolls” or “chips” (usually microscopic). Rolling can be caused by an overly thin edge. Chipping is often the result of the micro serrations being broken off. As an example: the FRN Caly Jr SE (black) had a reputation of the serrated points breaking off. This happened because the Caly Jr is already a thinly ground blade, and a serrated edge just makes it weaker. Serrations on an edge are just like a sharpened point of a pencil in that; the thinner it gets, the weaker it gets. Likewise, when a person gets their knife hair popping sharp, yet doesn’t use the finer grits to “fine tune” that edge, there is more chance for chipping because there are more serrations, and they are weaker than fewer serrations (like comparing Spydercos serrations to Cold Steel’s “fine toothed” serrations). That is why a polished edge will stay sharper than one that isn’t polished (all other things being equal), because the polished edge has fewer micro serrations (if any), and they are stronger than the micro serrations of a non-polished blade.

[JDEE]

Posted by Ghostrider That is why a polished edge will stay sharper than one that isn’t polished (all other things being equal), because the polished edge has fewer micro serrations (if any), and they are stronger than the micro serrations of a non-polished blade.

Not necessarily so. It depends on the material being cut EG in rope tests an aggressive edge out cuts a polished edge. Take and S30V with a polished edge and a AUS-6 blade with an aggressive edge and the latter will out cut the former. The reverse applies in cutting a material like wood. I always work on the principle of a polished edge for push cuts and an aggressive edge for slicing cuts.

[JDEE]

Why not just avoid the damage in the first place by digging with the back of the blade? That's what I do, and I don't have a dull or chipped edge when I'm done.
I mean really, it does not take a knife edge to cut dirt, if you see what I mean.

There are many many uses for the back of the blade, as long as it's not chamfered or rounded, like the Caly Jr. or, say, a Sebenza :D

I respect my fingers too much. Whilst I have great faith in the ParaM's lock the possibility of lock failure is there. I always treat a knife as being a slipjoint.

[ghostrider]

That is why a polished edge will stay sharper than one that isn’t polished (all other things being equal), because the polished edge has fewer micro serrations (if any), and they are stronger than the micro serrations of a non-polished blade.
Not necessarily so. It depends on the material being cut EG in rope tests an aggressive edge out cuts a polished edge. Take and S30V with a polished edge and a AUS-6 blade with an aggressive edge and the latter will out cut the former. The reverse applies in cutting a material like wood. I always work on the principle of a polished edge for push cuts and an aggressive edge for slicing cuts.

JDEE,
I’ve read this post and am confused. I don’t disagree with what you said; I just don’t see how it relates to what you quoted from my post. :confused:

I may be missing something, but I really think you and I are talking about two different things here. You seem to be talking about how well an aggressive edge cuts compared to a polished edge. I was talking about how well either of then keeps that edge. I understand that a polished edge may not work as well at cutting certain mediums (such as rope) as an aggressive edge, but does that mean that the polished edge won’t hold it’s edge better than the aggressive edge. Will the wood be more damaging to the polished edge than it will be to the aggressive edge? Will rope be more damaging to the aggressive edge than it will be to the polished edge? I understand that the material being cut will affect which edge type cuts better, but will it also determine which edge type looses its sharpness faster?

[JDEE]

What I am trying to point out is that a polished edge does not remain sharper then an aggressive edge in all instances. It is a matter of what the blade is being used for - the debate has gone on over a period of time those in favour of polished edges and those in favour of aggressive edges have their positions. What my position is that it depends on what the knife is used for and again I use the rope example a polished edge will not remain as sharp as an aggressive edge in cutting this medium so therefore in all instances a polished edge will not remain sharper for longer and of course the reverse will apply where a polished edge excells. It is the same as the arguement between thicker and thinner edges a thicker edge will remain sharper longer than a thinner edge when it comes to chopping eg. Again it is a matter of "horses for courses" if it was true that a polished edge will remain sharper than an aggressive edge then all knives would have polished edges but the user does not have a draw full of polished edges because different knives are meant for different tasks EG a butcher will have a boner has polished as he can because he wants it to push cleanly between meat and bone but his steak knife may not be polished to the same degree as it meant to slice mean, sinew and fat and a degree of aggressiveness is required as a polished edge will lose its sharpness quicker as more pressure is applied to slice the meat, sinew and fat this may not mean much to working in the kitchen at home but it does to a person who cuts meat for 8 hours a day.

There are so many factors relating to the sharpness and edge retention of knives that it is impossible to say that one factor is better then all others. I cant see where the arguement of a polished edge remaining sharper than an aggressive edge or one with more micro serrations would apply to a steel such as D2 which is renowned for its aggressive edge take that away by polishing the edge and IMO you would take away D2's advantage over other steels.

For the purposes of an EDC EG I suggest to people that they don't polish the edges of their blades it is just a waste of time and effort the only thing of value in it is being able to do it and getting self satisfaction from the process whereas if it was a specific use knife such as a boner, craft knife or racing axe polishing is an advantage and well worth the effort. It comes down also to the better an edge can cut a material the longer it will hold its edge. I have proven this with my Delica in rope cutting tests if I polish the edge of the Delica it will only make about 2/3rds of the cuts of a Delica with an aggressive edge therefore logic rules that the it must have kept its edge longer and remained sharper for longer but on push cuts on leather the reverse is the case. It is all of a matter of creating an edge that will last the longest for the tasks at hand.

[ghostrider]

Thanks for being so patient with me. I think I understand now. Because it takes more force to cut with a polished edge (in your rope example) than an aggressive edge, that added force on the polished edge serves to further degrade the sharpness of that edge.

Do I have it now? :)

[JDEE]

Yes and thanks for putting up with my ramblings sorry I took so long to explain it.

[DAYWALKER]

Aloha JDEE!

Neat story!

I once dug up some Gardenia plants with my ATS55 Rescue Jr. NO blade dings whatsoever, and I was going through cinder and lava rock! Then again, I did not have to go through an area as big as you did! :o

God bless and take care! :cool:

[ghostrider]

Yes and thanks for putting up with my ramblings sorry I took so long to explain it.
Are you kidding me! :eek:

Mr. John. I enjoy your ramblings because I often find myself learning from them. I know you sell knives (don't you also dabble in making them), and I know you test these theories of yours, as well as the knives you report on. I hardly consider illistrating them as well as you do "rambling".

Thanks to you, I learned something I should have figured out on my own, but hadn't thought of before.