Wharncliffe neck/pocket fixed blade design?

[Lucky Bob]

So, I've been wanting to make my "perfect" EDC urban-utility fixed blade for a long time, finally came up with a design with which I'm reasonably pleased, and wanted to know what y'all thought!

Design is a shameless hybrid of the Todd Begg Tree Frog and a semi-custom wharncliffe (note a trend here? ) I used to have from Les Voorhies. 2" blade is going to be of .103"x1.25" CPM-154 stock I already have, with a 20 degree cant below the main line of the handle. Handle is going to be 1/8" paper phenolic composite (not the wood rendered below) over skeletonized full tang with exposed lanyard hole.

I know that no plan/design survives contact with the enemy/grinder, but I enjoy CADD a bit too much not to go whole hog!

EDIT: See updated rendering downthread at http://www.bladeforums.com/forums/s...et-fixed-blade-design?p=16771485#post16771485

So, what do y'all think of this newb's attempt? Thanks!

 

[HSC ///]

i'd suggest this
smooth out my red mark of course

 

[Kevin McGovern]

Very stabby. I'm not sure what the intended use is, but in my day to day life, I would be concerned with snapping that tip off. I would make it more towards the sheeps foot profile. If it's sole purpose was self defense (last ditch scenario), I'd straighten it out a bit. I am a big fan of the kwaiken style for carry self defense. I feel it offers more options to the everyday user. Of course this i just my personal opinion.

 

[FunkCoaster]

Continuing off of Harbeer's feedback, if a user wants to cut something that's flat on a table, they will not be able to get the full cutting edge on the table. This isn't inherently wrong, but with a chef's knife, for example, it would prohibit certain types of cuts.

I may be wrong, but is the region below the first finger is intended as a striking surface? If so, it seems to be only a hair past the line of the tip-handle. So if striking a surface, the blade or handle may also strike. This could be mitigated by reducing the cant angle.

Lastly, a reverse grip may be uncomfortable. If a reverse grip is a consideration, maybe a prototype cardboard cutout would help explore that.

Overall, it looks great! My notes above are intended to ensure your EDC goals aren't impinged upon by those usages.

 

[Lucky Bob]

Thanks for the feedback, all! I'll be honest, this has ~0 intended self-defense application, just EDC utility. My old sensei taught knife-fighting as well, and I learned that I was better off not potentially handing someone a knife

The "sub-hilt" is really just for leverage. I have a smaller (wharncliffe...) necker that I designed years ago which basically just ends up with a thumb-and-forefinger grip, and the protrusion gives a lot more leverage in that kind of situation. I'm going to be doing some cardboard and/or wood prototypes, so we'll see how useful/necessary it is with an actual three-finger grip. I'll also see how much @FunkCoaster's issue with the cant getting in the way of the edge on a surface.

I'm less worried about the tip strength (and have the computer tech to see how much force it would take! >_>); I've been using a ZDP-189 Leek (with its incredibly pointy, potentially brittle tip) for years, and it was fine until it went through the wash somewhat recently!

Any aesthetic suggestions? Thanks!

EDIT: My quickie simulation shows that the tip would snap off at around 5lbs lateral load. Sufficed to say, I'll be changing that!

 

[HSC ///]

Continuing off of Harbeer's feedback, if a user wants to cut something that's flat on a table, they will not be able to get the full cutting edge on the table. This isn't inherently wrong, but with a chef's knife, for example, it would prohibit certain types of cuts.

I may be wrong, but is the region below the first finger is intended as a striking surface? If so, it seems to be only a hair past the line of the tip-handle. So if striking a surface, the blade or handle may also strike. This could be mitigated by reducing the cant angle.

Lastly, a reverse grip may be uncomfortable. If a reverse grip is a consideration, maybe a prototype cardboard cutout would help explore that.

Overall, it looks great! My notes above are intended to ensure your EDC goals aren't impinged upon by those usages.

Nicely said
I'd further add the radius on the spine and handle seems dramatic. Too rounded imo

But the tip is great for box cutting

Recently I'm working on a gentlemans Edc folder and tried three variations. In knife design and execution subtle differences can make or break the knife. These three are the same but different.

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[Lucky Bob]

I'd further add the radius on the spine and handle seems dramatic. Too rounded imo

But the tip is great for box cutting

Radius? The curves along the length of the knife, or the contours of the knife scales? if the latter, that's alright, I just put some arbitrary contouring the scales in the computer model since it's going to be freehand, which is a pain in the butt to model on a computer.

I'll be honest, box cutting and the like is probably 99.9% of what this knife is going to get used for. I just looooove overkill!

 

[HSC ///]

Radius? The curves along the length of the knife, or the contours of the knife scales? if the latter, that's alright, I just put some arbitrary contouring the scales in the computer model since it's going to be freehand, which is a pain in the butt to model on a computer.

I'll be honest, box cutting and the like is probably 99.9% of what this knife is going to get used for. I just looooove overkill!

This radius

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[Lucky Bob]

Huh, alright! I have pretty small hands, which probably helps, but I'll keep an eye on that as an issue in prototypes, thanks.

 

[Lucky Bob]

For what it's worth, I significantly changed the design based on the wood and cardboard prototypes I've made. The choil was way too small, and the handle was too small for anything other than a thumb-and-forefinger pinch grip. This is what I'm about to make a junk-steel prototype (since the CPM-154 I have is expensive!) out of, with the same overall lengths:

 

[Josh Rider]

Looking good. The choil/Spanish notch is usually bisected by the plunge though. I wish I had your cad skills!

 

[Drew Riley]

The biggest thing I'm seeing is that point just behind where the index finger goes. It just screams "hot spot" to me, especially in a reverse forward grip. It just looks like it'd dig right into the palm, and overall just limit the amount of comfortable grips you might have with the knife.

 

[Lucky Bob]

Looking good. The choil/Spanish notch is usually bisected by the plunge though. I wish I had your cad skills!

Thanks! The plunge and sharpening relief notch (too small to be a choil, too simple to be a Spanish notch?) have evolved over the course of the design. Originally, the plunge was going to be swept with the same radius as the notch, so that the ricasso and start of actual blade grind lined up with the handle-side and center of the notch respectively. I decided I wanted a somewhat more gradual plunge, but I figured the center of the notch should stay aligned as shown, since the point is to delineate the cutting edge. In the incredibly unlikely case that my *very first knife* will have a sufficiently defined plunge so as to make any difference, I may line up the tip-side of the notch with the tip-side of the plunge. I spent like an hour looking at custom knives, and couldn't find any examples I'd consider definitive of where the notch should go

As for CADD, I'm just glad that my MechE degree is good for something! (If I ever end up doing CNC machining as planned, I'm going to have to figure out how to computer-model organic, compound curves for handles. That's going to be a ton of fun...)

The biggest thing I'm seeing is that point just behind where the index finger goes. It just screams "hot spot" to me, especially in a reverse forward grip. It just looks like it'd dig right into the palm, and overall just limit the amount of comfortable grips you might have with the knife.

I actually went back just after doing this rendering and rounded off the design for that point to the same radius as the scales. I'm not too worried either way, though; the knife is just for utility, so I don't expect any usage outside of saber, Filipino, hammer, or paring grips, or with pointer finger along the spine. (Does that grip even have a name??)

 

[woodwrkr221]

I've made a half-dozen or so Wharncliffe utility knives for my brother and his co-workers at their nuclear power plant. They use them for communications and electrical work with wiring and what not.

I've got to agree with HSC/// in post number 2.

The tip of your blade design is a bit too pointy. The angle between the edge and the spine at the tip needs to be perhaps 10 degrees to 15 degrees steeper.

My first couple were pointy like your design but my customers quickly requested a less pointy tip for the blade. This will give the tip more support and strength.

 

[kuraki]

Very Leekish. I like it. While the needle point is fragile, it's sure handy sometimes. Like shop expedient metal sliver removal surgery

 

[Lucky Bob]

The tip of your blade design is a bit too pointy. The angle between the edge and the spine at the tip needs to be perhaps 10 degrees to 15 degrees steeper.

I just did some measurements; the original design I posted had a tip angle of just over 30 degrees. The one I posted earlier today is just under 45. Do you still think it needs to be steeper?

@kuraki: Thanks! That's what I was going for

 

[woodwrkr221]

I just did some measurements; the original design I posted had a tip angle of just over 30 degrees. The one I posted earlier today is just under 45. Do you still think it needs to be steeper?

@kuraki: Thanks! That's what I was going for

Yeah, maybe just a bit steeper.

It's hard to put a number to it but it probably needs to be over 55 degrees or so if your second design is 45 degrees.

My EDC is a Kershaw Leek. I just held it up to the screen in front of your second design and as pointy as the Leek is the very tip is just a bit steeper than your second design.

 

[Lucky Bob]

I appreciate your input, but I think we're going to have to agree to disagree on this one. I just pulled out an old Leek (my ZDP EDC leek's tip busted off in the wash a bit ago, but I'm super surprised I ever bought a partially serrated Leek!), and the rendering I posted today is significantly less acute at the tip than the leek, not to mention that the rendering is tilted slightly away from the "camera." The rendering/wireframe I posted originally is only slightly more acute than the Leek to which I'm comparing.