Nathan the Machinist
KnifeMaker / Machinist / Evil Genius
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Feb 13, 2007
- Messages
- 17,501
The Field Knife was designed as a collaboration with Lorien Arnold. It is a well made, no frills, high performance utility knife. The steel is Crucible CPM 3V at HRC 61-62 with the fully optimized heat treat with very good edge retention and edge stability. You'll be surprised how sharp this gets and how well it holds an edge. If you have never used 3V this hard and thin, it is gonna blow your mind.
This steel with this heat treat will support a fine edge, so this was taken down to .015" before sharpening and it was sharpened 18 degrees per side. This is relatively acute and it cuts well, but is very durable. This batch is also lightly hand ground after machining to give it a slight convex grind.
Some might consider this a tactical knife but the point is not reinforced and it is not shaped or balanced as a weapon. It's reasonably thin behind the edge. It is a hard working cutting tool, a big skinning knife and woods knife. There is a pry/scrape in the tang.
The handle is ergonomically designed for a standard forward, reverse, saber and pinch grips for an average to relatively large hand. The tang is internally skeletonized. The scales are 3D sculpted CNC machined. The blade is made of 3/16 3V with a heat treat that has been optimized to maximize edge stability in rough use. Despite being relatively thin it is durable. You can baton with it. You might damage the fine edge if you set your mind to it, but the knife itself is practically unbreakable.
A side effect of this heat treat is a higher percentage of free chromium, so although it is not stainless, it is nearly so.
Specs:
3V, tested 62 HRC, .188 thick at ricasso
This 3V is a fully optimized 3V for this hardness and application
Total length 9.75
Blade length 4.625
Weight 8.0 oz
Grippy 3D machined scales in micarta or G10
Black oxide treated 18-8 stainless steel fasteners
Jared Corry sheaths are custom made for these knives and are well designed and well made. They can be worn vertical or horizontal and can be configured for left hand or right hand carry.
Tell me what scale option you choose and I'll build it. There are ten knives available in this sale. The knives in the picture are not the knives you will receive, these are old pictures that show the scales options and finish. The knives need scales and sharpened and there are ten of them so there is quite a bit I need to do, so they will not ship until end of next week.
Rather than just take my word for it I made a video:
[video=youtube;1w1_WX_fNN8]https://www.youtube.com/watch?v=1w1_WX_fNN8[/video]
These are all field grade, as machined and stonewashed.
$235 in micarta, black or brown
$245 in solid color G10, black, OD green, blue
$255 in multi color G10, OD green, toxic green, brown, orange / black
(we're out of OD green/black G10)
There is one set of Terotuf laminated over thick black micarta not shown, $265. Terotuf is unbuffed. It is about performance, not pretty. If your hands get slippery when they sweat this is what you want.
The various colors and material choices are available in limited quantities, some are just one or two, so it is first come - first serve.
Includes a good kydex sheath.
Shipping in the USA is $10.
These knives are unusual because they are machined. I do this in my shop on industrial CNC machine tools. A WIP thread documenting my technique can be found here: http://www.bladeforums.com/forums/showthread.php/1048443
I take paypal, cash, check or MO.
Thanks for looking,
Nathan
Some thoughts about 3V and heat treat:
3V was originally developed for the tool and die industry for difficult stamping applications. The heat treat used in that application, which uses the secondary hardening hump, results in good toughness and abrasion resistance in that application and minimal part growth after heat treat, which is critical in tool and die. But, the carbon lean martensite, secondary carbides and retained austenite that decomposes in temper rather than a part of the primary quench all lead to issues with reduced edge stability in a knife edge. The thin geometry of a knife edge is not found in a stamping tool, and tiny areas of weakness become like the perforations in a postage stamp, allowing an edge to roll over, chip and generally behave "mushy". This sort of thing is so common in today's complex super steels and stainless steels that people just accept it as normal.
We have been tweaking 3V for cutlery for a while now, improving it for knives incrementally. There are a number of versions of these tweaks from me and other makers, but they can all be described as a "low temperature tweak". Basically, it involves avoiding the secondary hardening hump, and when done right reduces structures that are harmful to edge stability, but requires addressing retained austenite without a high temper. A happy side effect of leaving the carbon in the martensite is it doesn't tie up all the chromium, leaving 3V very nearly stainless.
All of my 3V over the years has been tweaked in one way or another.
Last year some of us running a tweaked 3V ran into some trouble with some that didn't respond like we expected. Those of us makers who test work from every batch noticed it. It required some re-work, but we addressed the issue, and it prompted us to try to better understand what was going on with the alloy and to pursue a fully optimized 3V. So, Guy Seiferd (Survive Knives), Dan Keffeler and I invested the time and resources to more deeply investigate variables and develop a more complete understanding of the alloy, its quirks, and develop an optimized heat treat protocol for it. This is one reason my output was low earlier in the year, because I'd spent a significant portion of the winter in R&D mode.
Our previous tweaks to 3V had already made it significantly outperform the industry standard, so the fully optimized version is not a night and day improvement over our previous work, but the difference is significant, so in order to differentiate between this optimized 3V and previous tweaks we are putting a Delta symbol with the 3V on the knife to denote change. Otherwise, it would be difficult to differentiate.
The pictures above are old pictures showing a previous batch, the knives in this sale are the new heat treat and look like this:
If you have an old Field Knife don't feel bad like you're missing out, they had a very good heat treat and perform extremely well. The new heat treat achieves the same level of edge stability and edge retention with a higher degree of ultimate toughness. The old heat treat was already a very good performer (best in the industry) so unless you're cutting nails, most folks would not notice a difference.
If you're curious, this is a video that illustrates the difference between the fully optimized 3V and an old industry standard heat treat: https://www.youtube.com/watch?v=6imZ4Vo8iwA
The heat treat for these Field Knives is the new protocol, but left a point harder because it's a smaller blade.
There is a small price increase. The new heat treat has more steps, takes longer and costs more to perform. But the actual cost increase per blade is pretty trivial and well worth it.
This steel with this heat treat will support a fine edge, so this was taken down to .015" before sharpening and it was sharpened 18 degrees per side. This is relatively acute and it cuts well, but is very durable. This batch is also lightly hand ground after machining to give it a slight convex grind.
Some might consider this a tactical knife but the point is not reinforced and it is not shaped or balanced as a weapon. It's reasonably thin behind the edge. It is a hard working cutting tool, a big skinning knife and woods knife. There is a pry/scrape in the tang.
The handle is ergonomically designed for a standard forward, reverse, saber and pinch grips for an average to relatively large hand. The tang is internally skeletonized. The scales are 3D sculpted CNC machined. The blade is made of 3/16 3V with a heat treat that has been optimized to maximize edge stability in rough use. Despite being relatively thin it is durable. You can baton with it. You might damage the fine edge if you set your mind to it, but the knife itself is practically unbreakable.
A side effect of this heat treat is a higher percentage of free chromium, so although it is not stainless, it is nearly so.
Specs:
3V, tested 62 HRC, .188 thick at ricasso
This 3V is a fully optimized 3V for this hardness and application
Total length 9.75
Blade length 4.625
Weight 8.0 oz
Grippy 3D machined scales in micarta or G10
Black oxide treated 18-8 stainless steel fasteners
Jared Corry sheaths are custom made for these knives and are well designed and well made. They can be worn vertical or horizontal and can be configured for left hand or right hand carry.
Tell me what scale option you choose and I'll build it. There are ten knives available in this sale. The knives in the picture are not the knives you will receive, these are old pictures that show the scales options and finish. The knives need scales and sharpened and there are ten of them so there is quite a bit I need to do, so they will not ship until end of next week.
Rather than just take my word for it I made a video:
[video=youtube;1w1_WX_fNN8]https://www.youtube.com/watch?v=1w1_WX_fNN8[/video]
These are all field grade, as machined and stonewashed.
$235 in micarta, black or brown
$245 in solid color G10, black, OD green, blue
$255 in multi color G10, OD green, toxic green, brown, orange / black
(we're out of OD green/black G10)
There is one set of Terotuf laminated over thick black micarta not shown, $265. Terotuf is unbuffed. It is about performance, not pretty. If your hands get slippery when they sweat this is what you want.
The various colors and material choices are available in limited quantities, some are just one or two, so it is first come - first serve.
Includes a good kydex sheath.
Shipping in the USA is $10.
These knives are unusual because they are machined. I do this in my shop on industrial CNC machine tools. A WIP thread documenting my technique can be found here: http://www.bladeforums.com/forums/showthread.php/1048443
I take paypal, cash, check or MO.
Thanks for looking,
Nathan
Some thoughts about 3V and heat treat:
3V was originally developed for the tool and die industry for difficult stamping applications. The heat treat used in that application, which uses the secondary hardening hump, results in good toughness and abrasion resistance in that application and minimal part growth after heat treat, which is critical in tool and die. But, the carbon lean martensite, secondary carbides and retained austenite that decomposes in temper rather than a part of the primary quench all lead to issues with reduced edge stability in a knife edge. The thin geometry of a knife edge is not found in a stamping tool, and tiny areas of weakness become like the perforations in a postage stamp, allowing an edge to roll over, chip and generally behave "mushy". This sort of thing is so common in today's complex super steels and stainless steels that people just accept it as normal.
We have been tweaking 3V for cutlery for a while now, improving it for knives incrementally. There are a number of versions of these tweaks from me and other makers, but they can all be described as a "low temperature tweak". Basically, it involves avoiding the secondary hardening hump, and when done right reduces structures that are harmful to edge stability, but requires addressing retained austenite without a high temper. A happy side effect of leaving the carbon in the martensite is it doesn't tie up all the chromium, leaving 3V very nearly stainless.
All of my 3V over the years has been tweaked in one way or another.
Last year some of us running a tweaked 3V ran into some trouble with some that didn't respond like we expected. Those of us makers who test work from every batch noticed it. It required some re-work, but we addressed the issue, and it prompted us to try to better understand what was going on with the alloy and to pursue a fully optimized 3V. So, Guy Seiferd (Survive Knives), Dan Keffeler and I invested the time and resources to more deeply investigate variables and develop a more complete understanding of the alloy, its quirks, and develop an optimized heat treat protocol for it. This is one reason my output was low earlier in the year, because I'd spent a significant portion of the winter in R&D mode.
Our previous tweaks to 3V had already made it significantly outperform the industry standard, so the fully optimized version is not a night and day improvement over our previous work, but the difference is significant, so in order to differentiate between this optimized 3V and previous tweaks we are putting a Delta symbol with the 3V on the knife to denote change. Otherwise, it would be difficult to differentiate.
The pictures above are old pictures showing a previous batch, the knives in this sale are the new heat treat and look like this:
If you have an old Field Knife don't feel bad like you're missing out, they had a very good heat treat and perform extremely well. The new heat treat achieves the same level of edge stability and edge retention with a higher degree of ultimate toughness. The old heat treat was already a very good performer (best in the industry) so unless you're cutting nails, most folks would not notice a difference.
If you're curious, this is a video that illustrates the difference between the fully optimized 3V and an old industry standard heat treat: https://www.youtube.com/watch?v=6imZ4Vo8iwA
The heat treat for these Field Knives is the new protocol, but left a point harder because it's a smaller blade.
There is a small price increase. The new heat treat has more steps, takes longer and costs more to perform. But the actual cost increase per blade is pretty trivial and well worth it.
