Home Forums Gear Knives and Blades Edge Pro vs hollow grind

Journeyman,
Have you found 18/15 to thin for the D2 that might show up as brittleness or edge chipping?

I do my kitchen knives at 18/15 but they are very thin to begin with. I also have a couple capers that are 3/32nds ATS34 that I use the same angles for but I use them for the very delicate work.

It's been my experience that D2 in general, like the under-hardened stuff from most factories, loses the edge from the carbides disjoining from the matrix quickly below about 18, but that from guys who know what they're doing (it's been rumored that Bob D fits this category :D) in the heat treat/grind 15 per side, or 15/18 is about optimum. When sharpening for others less knife knutty, I usually suggest they buy a sharpmaker and then set the profiles at 15/20 for them to match that.

I routinely take S30V and S35VN to 13 without any issues due to the smaller, harder and evenly distributed vanadium carbides...

I gotta tell you experts a trick. If I get a custom handmade knife,wether flat ground,hollow ground,Scandi,convex edge.....
If I dull it & can't re sharpen it with what I use,witch is diamond bench stones,Arkansas stones & leather strop,I pretty much know right then & there I won't be keeping that knife
Period,end of story
As far as collection,I've seen beautiful knives as dull as butter knives,but knowing,they will never be used

Bottom line,Any decent cutlery steel + proper Heat treat + grind (thin at the edge) = Edge Geometry

You should not have to have a problem re sharpening.If you do,the knife does not have good edge geometry.

Vince, if you recall our phone conversations you know we think a lot alike on knives. (you turned me on to Moore and Howser)

To me it's simple: Geometry cuts. Steel, heat treat and grind determine for how long it cuts...worst deepest frikken cut I ever self-inflicted on my own precious hide was from a sardine lid. In my years in mountain search and rescue we hauled out several guys with major serious lacerations from changing "dull" broadheads (main reason I never recommend Havalon pirantas to guys I don't know.)

Diamonds are fine for some steels, less suited to others. In general carborundum is ALWAYS superior. Stropping compounds vary from crap to hyped.

My interest in knives. besides the theoretical from working in materials engineering for over three decades, is in critters, and pretty much only critters, with a smattering of the practical necessary to owning and maintaining a large ranch in the west and in helping my son with his thesis on steels. I do some 100 game animals, and on my ranch a few dozen of our 1200 beefs and other larder critters, per year to form the basis of my opinions. Obviously others' needs, like cutting cardboard, killing zombees and ninjas and such will vary!

I never met but a few knives in some 600 customs I couldn't like. One was a Dozier fwiw.

Handmade knives,hand ground,you know then,from any one maker,you can get a good cutter,and a not so good cutter. Hopefully all good.
But keeping it simple,if you use it but can't do the maintenence on it,that presents a problem for me.

Sums it up perfectly IMO. I gave grandpa a 440V from Wilfred works a few years back and he cussed it like crazy. I love it. What can I say?

Those Bose Fella's swear by that steel
I have one from that shop,in 440V & it is a great cutter.
I have had & sold some hollow ground knives by Mike Miller in that steel that were awesome cutters.

If you take your index finger & thumb,and pinch the grind of a blade (loosely),and run down the blade & feel for thin & even. If you do this enough times you will get good at knowing if the grind is good.
I have seen knifemaker videos where they do this,handling a knife while talking,almost instinctively. This part of the grind,is known as the "land". Old time cutlers refer to it as this. You want the land thin & even.Most times the un even ness will be,thicker at the tip.Its harder to grind the tip section thin & not change the blade profile you are doing. This is where the skill is needed.

I have taken knives that were thick at the edge & dull. Re profiled them with the stones I mentioned previously,changed the angle & put a convex edge on them,hand lapped & got them dam sharp. By hand,about 15 ,20 min job.

So when I hear a guy who has a pretty much proven hi tech sharpener & knowledge,as in the beginning of this thread by the OP,and has a hard time,that knife gave him a hard time(built by a pro,reknowned)...Thats a knife I don't want. Regardless of the maker

Some guys hammer blades into telephone books & cinder blocks for tests. I bet they are not sleeping with both hands outside the sheets.

These days you can get dam good production blades at good prices ,some will exceed custom makers prices.But a handmade knife should cut & be able to be maintained,same as a production knife.At all levels of cost. Collection,well,you're not gonna cut nothing,soooo....

Damned, I knew the tempo had to pick up here eventually. Some good thoughts/experience to ponder.
I certainly am not taking anything away form the knife mentioned to start this thread. The knife belongs to frogman43. If I get another look at it we will see what we can see.

I have a couple hollow ground blades my nephew made around so I will put them on the Edge Pro and see what becomes of that.
I did get that knife pretty damned sharp. I went to 1000 grit, but as noted above 600 might be optimal for that steel and grind.

I really like it when a topic like this gets going.
Tim

When I get some time freed up from my "honey do" list I'll give you a call Tim and drive down to give you another look at that Dozier.

Jman do you think "proper heat treat" can be defined by a single number? For example if D2 is taken to 62rc do you feel that every piece of D2 taken to 62rc will have the same properties or do you think someone like Dozier is doing something a little different?

Also do you think that a cryo treatment will help regarding the degradation of the carbides if the edge is taken to thin? I know a lot of barrel makers like to chamber on cryo'd barrels because they indicate the matrix is much smoother and cutting is much cleaner. I also agree on S30V, I think a thin blade and a steep profile accents is cutting abilities.

I take the opposite approach on blade hardness. You need to remember that D2 is a die steel, and as such, is very abrasive resistant.

Rc62 is fine for a draw or swaging die, but I think it is a bit hard for a knife, if for no other reason than the Rc 62 is going to be somewhat brittle.

All of these newer and high hardness knives are going to be difficult to re-sharpen. Of course, D2 is not a new steel, having been around since the early 1900s.

Whether or not this difficulty in re-sharpening is worthwhile, it all depends on where you are at the time. In the woods and it is the only knife you have with you, and no way to re-sharpen, is a bad place to be with a knife that tests Rc62. Also, it is going to be very brittle.

There might be secret ways of heat treating steel, to make it perform better, but I do not know of any of these methods. Some knifemakers claim there are secret ways, and other makers chaim there is not. I don't think there is, but my opinion counts very little, if any at all.

One place that I know of that will alter a knife's performance is tempering temperature, but that has been known for many years, and is not hardly a secret.

Cyro quenching D2 might show some improvment in both brittleness and strength at the very edge, the cutting edge, of a thinly sharpened blade, but I do not have any information on cyro quenching D2.

Seems like I just wrote a bunch of stuff that is meaningless to most people. Oh, well.

steel heattreating is a subject best understood by the engineers making the alloys & the determined knifemakers in search of methods to extend the alloy performances of various metals they are using. some knifemakers actually understand concepts such as modulus of elasticity , coeiffient of expansion, & charpy index.i ceryainly do'nt claim to be a steel wizard but look at the knifemakers blades that can perform far above the average expectations of a steel. triple tempers, cryo cycles, & other tweaks are not bull. may i mention that ed fowler 's method of 52100 performance, snipers bladeworks 1095 at 65 r.r. [not brittle], phil hartfields, amazing a2, busses infi, & many other masters is not fiction but has been proven in the field many years. i recently tested a blade by rick menefee made of a common alloy [154cm], this blade out cut by 50% the super powdered alloy zdp189 . 154 is a fairly uncomplicated, much older steel that menefee tweaked to outperform one of the supersteels developed fairly recently & considered to be a very abrasion cutter. yes there are tricks not known by average knifemakers, these tweaks are what many of informed users search for in their custom purchases,--cranky72

You need to try Jerry Halfrich's cpm154 it spanked a M4 blade from Krein on a Montana elk.

Well, I sharpened a couple different hollow ground blades today on the Edge Pro. Great edges with no problems. These blades were as thick as the Dozier, but shorter and not as much belly in the frontal section.
I think it is geometry at the heart of the issue.

Still some great stuff brought forth here.
Tim

No better advice than this! I think old Vinie has it figured out.