OAUSA Net - September 14, 2017 - Edged Implements

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OAUSA Net - September 14, 2017 - Edged Implements


Post by DaveK » Mon Sep 11, 2017 1:31 pm

Part of your essential outdoor gear, which should be in your vehicle as well as what you always carry on your person, are edged implements, AKA knives. Edged implements go beyond just knives, however, and include hatchets, axes, shovels, machetes, saws, multi-tools, and even such things as chain saws. The net will primarily focus on knives, but we will broaden the scope, if there is sufficient interest.

Our guest for this net will be Daniel Humphries, KI7NAI, who is an engineer with a great deal of knowledge on this subject. Post your questions or comments here and join us on the net.


Tonight the spotlight is on an ammunition handloading product. Anyone who loads their own ammo, in most cases, will have to own a powder dispenser. Most of the major manufacturers offer at least one dispenser. Some offer different grades with the highest often bearing the name of "bench rest". Without getting into the details of what factors contribute to accuracy, I will only say that consistent powder charge weight will help significantly in getting the most accuracy from your firearm. There are, of course, other factors, but that will be a topic for a later net.

Many handloaders don't want, and probably don't need, to weigh each charge. So, the mechanical powder dispenser will be your best bet. Most powder dispensers fall withing the "adequate" category, but for those who are looking to get the most accurate powder dispensers on the market, the field narrows considerably.

When it comes to consistency and precision, there is one powder dispenser that is among the very best. It's a little pricey, but you get what you pay for. Made in the USA and guaranteed for life, the Harrell Culver Style dispenser has few peers, if any. Sinclair International offers all models of the Harrell measures and this is what they have to say:
The Harrell Premium measure will throw changes from 6-120 grains, so it will work for just about any cartridge you load. The 16 ounce powder bottle lessens the need to refill as often (also accepts most 1 pound containers like Hodgdon, Accurate, etc). This measure has needle bearings built into each side of the metering insert to give it the smoothest feel of any powder measure we have ever tried. If you want one measure to serve all your reloading needs, the Harrell Premium will give you a lifetime of service.

Each Harrell measure is built with a quality CNC machined aluminum body and an extremely accurate “Culver Style” brass metering system. All of the measures throw with the same accuracy and repeatability, and can be dialed back to the desired charge on the click metering system at any time. Each Harrell measure comes with a clamp style mounting system, one appropriate sized powder bottle with a bottom plug and two 4" drop tubes, one 3⁄16" and one ¼" ID (Schuentzen has a shorter drop tube). There are no finer custom powder measures on the market. (http://www.sinclairintl.com/reloading-e ... 38305.aspx)
Harrell Powder Dispenser2.jpg
Harrell Powder Dispenser2.jpg (1.05 MiB) Viewed 604 times

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 8:02 pm

Hardness and toughness

Hardness refers to a material's ability to resist deformation, in the knife industry (as well as any other metal working industry) hardness is measured using a rockwell hardness tester, a special tool that uses a diamond tool of a specific geometry that is forced into the metal with a specific force, the depth of the resulting indentation determines the hardness. For knife blades hardness is typically expressed in HRC or Rockwell C. Normally cutlery falls in the range of 50-65HRC depending on the material and the intended use.

Ductility is a material's ability to deform under stress, a ductile material will bend before breaking. In knife blades ductility isn't necessarily desirable, but it's often referred to when comparing steels because ductility relates to toughness. Toughness is a combination of ductility and strength, it is normally measured with a Charpy notch test where a sample of a specified geometry is impacted with a specific weight dropped from a specific height and the energy absorbed in the impact is recorded as the toughness. For blades this is normally 20-85 Ft Lb depending on the material and the intended use.

Hardness and toughness are a tradeoff, harder materials have lower toughness and tougher materials have lower hardness. Compare a glass bottle to a plastic bottle, the glass bottle is very hard but will easily crack if impacted, the plastic bottle is very soft, but will resist impacts.
rolled edge.jpg
an overly ductile blade with low hardness is prone to rolling the edge
rolled edge.jpg (173.02 KiB) Viewed 823 times
chipped edge.jpg
An overly hard blade is prone to chipping
chipped edge.jpg (142.54 KiB) Viewed 823 times
Ultimately hardness determines wear resistance, which is the ability to cut through abrasive things without dulling. Knife steels have been developed to maintain high toughness at high hardness.
Steel Comparison.jpg
comparison of various steels
Steel Comparison.jpg (49.61 KiB) Viewed 823 times
Last edited by KI7NAI on Mon Sep 11, 2017 9:56 pm, edited 1 time in total.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 8:19 pm

In the last 2 decades Powder Metals have grown popular, with improvements in manufacturing processes the cost has dropped considerably and superior alloys have been developed. At this point anybody who is a knife enthusiast most likely owns one or several knives with a powder metal blade.
PM VS Conventional Steel.jpg
a micrograph comparing powder metal to conventional metal
PM VS Conventional Steel.jpg (88.27 KiB) Viewed 823 times
The goal of powder metal is to provide a finer and more consistent grain structure. Because the metal is powdered and sintered the grain growth is limited by the physical boundary of the powder sphere. Highly alloyed steels can be produced with even distribution of small carbides, if the same alloy were produced with conventional manufacturing processes the carbide grains would grow together and become un-workable.
PM VS Conventional Steel Chart.jpg
Comparison of Powder Metal to Conventional Steel
PM VS Conventional Steel Chart.jpg (72.23 KiB) Viewed 823 times
Powder metal has tangibly superior characteristics compared to traditional steels, it can be heat treated harder for better wear resistance without sacrificing toughness. Theoretically the fine grain structure of powder metals allows for sharper edges as the small carbides are less likely to tear out during sharpening. In the real world, your mileage may vary.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 8:45 pm

Excessively hard, wear resistant steels can be very difficult to sharpen with common honing stones. Most of the powder metals will require diamond hones to sharpen
Diamond Hone.jpg
An inexpensive diamond hone
Diamond Hone.jpg (70.1 KiB) Viewed 821 times
Because of the difficulty sharpening high hardness steels great care should be taken to sharpen the blade with precise angles so you're only removing the minimal amount of material necessary. There are a number of sharpening systems, most of them are not inexpensive, Wicked edge, Edge Pro, Lansky, and others make sharpening systems for home sharpening with a very short learning curve.
Lansky.jpg (47.38 KiB) Viewed 821 times
Wicked Edge.jpg
Wicked Edge
Wicked Edge.jpg (85.92 KiB) Viewed 821 times
Edge Pro.jpg
Edge Pro
Edge Pro.jpg (58.54 KiB) Viewed 821 times
Polished Edge.jpg
Polished Edge.jpg (50.82 KiB) Viewed 821 times
A DIY version can be made inexpensively, this version uses automotive finishing sandpapers as an abrasive.
DIY Sharpener.jpg
A DIY Project
DIY Sharpener.jpg (87.48 KiB) Viewed 821 times
Last edited by KI7NAI on Mon Sep 11, 2017 9:21 pm, edited 1 time in total.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 8:55 pm

Crock sticks are a simple sharpening system using ceramic rods that are set at a specific angle, with a little practice these sharpening systems can provide very sharp edges
crock sticks.jpg
crock sticks.jpg (51.19 KiB) Viewed 821 times
The Spyderco Sharpmaker is another take on the crock sticks, it's a little more versatile for sharpening serrated blades, fish hooks and other unusual geometry.
Spyderco Sharpmaker
Sharpmaker.jpg (35.29 KiB) Viewed 821 times
Natural stones and waterstones have been used for centuries, they are still very useful for sharpening most steels, but require considerably more skill. Stones are almost always used in a progression from coarse to fine regardless of the sharpening system used, large bench stones, especially high quality Japanese waterstones can cost hundreds of dollars, much smaller stones are often used with sharpening systems, although the initial investment is high to pay for the sharpening mechanism, in the long run the cost savings of smaller stones or alternative abrasives makes the cost more comparable.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 9:00 pm

The work sharp electric sharpener is supposed to be user friendly
work sharp.jpg
Work Sharp
work sharp.jpg (57.29 KiB) Viewed 821 times
A paper wheel is another option
Paper Wheel.jpg
Paper Wheel
Paper Wheel.jpg (41.13 KiB) Viewed 821 times
Grinding wheels and other powered sharpeners require a lot of skill to use, it's easy to destroy a blade either by removing too much material or by overheating the blade when using powered equipment. Hand sharpening is recommended for anybody who isn't a professional.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 9:16 pm

There are lots of blade steels to choose from, an incomplete list includes
1. A2
2. D2
3. O1
4. M4
5. W1
6. CPM 3v
7. 52100
8. 154CM
9. CPM 154
10. ATS-34
11. 420HC
12. 440C
13. CPM S30V
14. CPM S35VN
15. CPM S110V
16. CPM 20CV
17. CTS 204P
18. M390
19. Elmax
20. 12C27M
21. 13C26
22. 14C28N
23. 8Cr14MoV

I'll talk about my experiences with most of these. Please share your experiences with any of these steels or others I haven't listed.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 9:48 pm

The two most common blade geometries are flat ground (or variatons of a flat grind) and hollow ground. How the blade geometry is formed plays an important role in how much the blade cost and the materials used.

Flat grinding is used for most high end blades with powdered metal steels.

Hollow grinding is a faster process that grinds both sides of the blade simultaneously. It's not very easy to see what's going on in this video but I'll discus in detail how the machine works during the net.

Flat ground blades are very strong, there is a lot of material supporting the edge, as the blade cuts into the material it is gradually wedged apart. A hollow ground blade creates a very thin cutting edge, these blades can perform very well, but the hollow grind can very abruptly wedge into a material when making deep cuts.

Scandi grinds found on Mora knives is a variation of a flat grind, the full flat grind found on many spyderco knives is another variation of a flat grind. Chris Reeves uses a proprietary process to form a very shallow hollow grind, it's nearly a flat grind with a very slight concavity that cuts very well. Many of the traditional slip joint folders were originally manufactured with a flat grind, as factories grew and demand increased some of the more recent models have moved to hollow ground blades, especially brands like Schrade, Old Timer, Uncle Henry, that have gone out of business and the names and trademarks were bought by Chinese factories.

My favorite grind depends on the usage, for an everyday carry knife I like a hollow ground blade, I find they cut through thin materials like packing tape, envelopes and cardboard easily. For camping or other outdoor activities where I might be cutting into something with considerable force I like a flat ground blade. I'm not a huge fan of serrated blades because of the difficulty sharpening the serrations, that said when the serrations are sharp, they do cut extraordinarily well.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Mon Sep 11, 2017 9:54 pm

handle materials
  1. steel
    Kershaw Leek with steel handle
    Leek.jpg (20.02 KiB) Viewed 635 times
  2. titanium
    Lionsteel SR1.jpg
    Lionsteel SR1 with Titanium Handle
    Lionsteel SR1.jpg (49.55 KiB) Viewed 635 times
  3. aluminum
    Swiss Army Classic.jpg
    Swiss Army Classic with Aluminum Handle
    Swiss Army Classic.jpg (76.69 KiB) Viewed 635 times
  4. G10
    Spyderco Tenacious.jpg
    Spyderco Tenacious with G10 handle
    Spyderco Tenacious.jpg (63.71 KiB) Viewed 635 times
  5. carbon fiber
    Zero Tolerance 0770.jpg
    Zero Tolerance 0770 with carbon fiber handle
    Zero Tolerance 0770.jpg (55.2 KiB) Viewed 635 times
  6. Micarta
    Esse Izula.jpg
    Esse Izula with aftermarket Micarta handle
    Esse Izula.jpg (71.54 KiB) Viewed 635 times
  7. FRN
    Benchmade Griptillian.jpg
    Benchmade Griptillian with FRN handle
    Benchmade Griptillian.jpg (32.97 KiB) Viewed 635 times
  8. wood
    lock back.jpg
    Buck 110 with wood handle
    lock back.jpg (23.25 KiB) Viewed 635 times
  9. bone
    Case Peanut.jpg
    Case Peanut with bone handle
    Case Peanut.jpg (15.14 KiB) Viewed 635 times
Last edited by KI7NAI on Thu Sep 14, 2017 8:39 am, edited 1 time in total.

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Re: OAUSA Net - September 14, 2017 - Edged Implements


Post by KI7NAI » Thu Sep 14, 2017 8:25 am

Lock mechanisms
Liner Lock
liner lock.jpg
Liner Lock
liner lock.jpg (57 KiB) Viewed 635 times
Frame Lock
frame lock.jpg
Frame Lock
frame lock.jpg (40.21 KiB) Viewed 635 times
Lock Back
lock back.jpg
Lock Back
lock back.jpg (23.25 KiB) Viewed 635 times
Axis Lock
axis lock.jpg
Axis Lock
axis lock.jpg (44.56 KiB) Viewed 635 times
Pushbutton Lock
Pushbutton lock.jpg
Pushbutton Lock
Pushbutton lock.jpg (23.97 KiB) Viewed 635 times

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