Anyone want to Review My Knife Design

Interest Groups Knife Making
#1

I have modeled an knife design for a backpacking knife. It is intended to be light but not stupid light. Which is to say that I want it to be functional. Mostly tasks like trimming loose threads, guylines, etc., but I might need to sharpen a stick for an improvised tent stake. I chose a sheepsfoot for a few reasons:

  • I don’t want to cut something unintended (Backpacking gear can be delicate, and i don’t want to spend a night cold and wet)
  • I wanted a design that is relatively easy to get very sharp
  • I wanted a design that will be relatively easy to execute (This is my first project where I’m actually making the blade)

I am thinking of using a high carbon steel. Rust is a concern, but the carbon Opinels are a popular choice.

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https://a360.co/2EDtCgU

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#2

I am primarily concerned about whether my hollow grind is reasonable or if I am likely to run into strength/durability issues. Major ergonomic problems that I don’t see, etc.
I expect to have to make a few variations to get a really great design due to small size (2" blade, slightly over 4" overall).

#3

Replying to remember. I’m in Amsterdam for the next few days, I’ll have more to say this weekend. Looks cool though.

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#4

Get back to eating cheese and wandering beautifully.

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#5

Massaged the design with the intention of shaving some weight. Is 1/16" too thin? The idea is that it would be a light duty, in a pinch kind of tool. Probably the toughest use it will see is sharpening a pencil or cutting some guy line.

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#6

Kinda depends. Are you looking to harden it (aka what kind of steel will you use)?

If you are still looking at high carbon steel, and you want to use it without a handle, I’d say a 1/16" is too thin for a couple reasons: First, you need about the thickness of a dime at the thinnest point to avoid warping or cracking during the heat treat, that gives you only about .023mm total for pre-hardening grinds (.013mm on a side), that ain’t much; second, 1/16 is gonna put a fair amount of pressure on a really small part of your hand, which will probably be fairly uncomfortable for cutting much more than butter. Put a handle on it and the math changes somewhat and we’d need to know how wide you want the blade to be.

The design is cool though, I’m a big fan of the sheep’s foot, I’d probably start with at least 1/8" and probably 3/16" to give yourself some meat to work with.

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#7

I really like the look you have here. I’d massage a few things possibly for my use. Add finger choils to and bottom at the haft and butt. Cold, wet, sweaty hands might really appreciate it. As below I’d go at least an eighth of an inch and probably a smidge thicker. For a working blade I would also consider increasing the handle to at least 3". Lastly, what type of sheath? I’ve done small kydex sheaths if I can be of any help. Good luck! Hope you post the finished product!

#8

I mean, it has a bulge and the blade is offset to create a bolster effect. I expect that I will hold this with 2-3 fingers and my thumb on the spine. The design is loosely based on a Vargo Ti knife. ti-clip-knife I want to keep knife and sheath under 1 Oz. Kydex would probably work for the sheath, that was my first thought.

#9

Are you planning to cut food with it? Just asking.

My only concern is with the heel of the blade and how there it isn’t flush. It will get in the way when sharpening or honing the blade.

#10

The top of the handle is well above the top of the spine: this will make the knife want to turn in the hand during use. The center axis for the handle is usually at or below the spine and above the knife edge.

This can be mitigated by pinching the sides of the blade in use but that doesn’t match how you said you planned to hold it.

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#11

If you’re going to use the knife for backpacking and outdoor use, I would want to point you toward a drop point or spear point, high carbon knife design like the one shown in the linked article. A Scandi grind makes outdoor and wood processing tasks easier. And the shape of the blade lends itself to a more natural sharpening motion. The 1/8” blade thickness is suitable for sturdy tasks without becoming too heavy in the hand with extended use. I purchased just the blade blank from Condor and made my own cocobolo wood handles for it. A blank goes for approx. $15-20.

If you want to make your own blade, this is an easier knife shape to fashion with just a KMG grinder. If high carbon and water concerns you, put a forced patina on the blade using white (or any) vinegar and/or yellow mustard. There plenty of You Tube videos that show you how to do it. I have several knives, But this seems to be my ‘go-to’ knife because of it’s superb utilitarian design. I highly recommend this design for outdoor use.

#12

Okay, that requirement changes everything. I humbly suggest that the gram-dieting that backpackers undergo be loosened for one’s knife. A solid, dependable knife will be more of you most valued assets in the field. Resist the urge to skimp. IMHO.

#13

I mean, lots of people are doing through hikes with no knife at all. Many more with a Swiss Army Classic (keychain size) or a Leatherman Squirt. I think those options are underwhelming, but I still don’t want to carry around a heavy knife. For hiking on an established trail, with a fair number of hikers, I just don’t see the need for it.
I think the general consensus is that I was being too much of a weight weenie, so I have drafted a revised design. I went back to 1/8" thickness while massaging the handle for more weight relief and less offset.

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#14

I like the redesign much better. I question whether the hole in the handle is worth the hassle: if the total weight is 1oz, including that missing mass would only add maybe 1/8th of that amount. It’d be more comfortable in the hand as a solid handle.

Here’s a tiny knife I made a while back which is similar, though less refined, than your concept. It was probably three inches long and was designed as a neck knife or toss in knife for a tackle box. It was made from auto coil spring on the induction forge at DMS.

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1BBB379D-9167-4885-85C3-C45D1D6AD760.jpeg3024×4032 2.69 MB

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#15

It’s a fair point. When it comes time to manufacture, I may end up just doing a round hole. Depends how I cut out the blank, really.

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#16

In its current iteration, the pocket hole is about 20% of weight.

#17

For an occasional knife like this you might just plasma cut it or grids it out of an old circular saw blade.

FWIW, there are some other neck knife outlines I put up on the Blacksmithing Committee drive last May. They are in SVG (Inkscape) format. I’d intended to try cutting these out on the plasma but never got around to it. The finger notches on the tiniest blades help with control since the tangs are so small.

In the same folder are some notes I put together on how to go about making a knife from a saw blade. They are pretty rough but you might find them useful.

N:\Blacksmithing\Patterns\Neck Knife Patterns

#18

Fair enough: I was eyeballing it. Still, that’d be and extra 1/5th of an ounce.

#19

I was planning to plasma cut it, so minimal extra work, just cleanup. I plan to use a Dremel (or Foredom/drill press attachment?) to cleanup the inside.

#20

If you’ve been trained on the MKG grinder, I’d recommend that for removing the bulk of the plasma cutter slag from the back of the blade. You can use a welding magnet as a handle to hold the blade flat against the platten. The KMG can also cut in your bevels: although we do not currently have a beveling jig for it, you can easily cut a tapered piece of wood to brace the blade against while grinding, once you determine the half-angle to use.

A pocket knife would typically have a 20-30 degree bevel total angle, so you’d use a 10-15 degree half-angle on the wood jig. A fillet knife would be finer (a 10-20 degree angle is sharper/leaner but less durable). A 10 degree half angle might be a good compromise…

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