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AR-Trvlr

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FK2 - Field Knife 2 / UFK – Utility Field Knife

The handle is very close to the same in profile, but wider in width, however the developed circumference (the size that you feel in your hand) is about the same as the original. This is because the shape is less planer and more rounded. I did this so the knife could be turned in the hand to offer more grip options for field craft work where the original kind of locked in at one angle. I've also tweaked the ass end of it to better accommodate a three finger grip. That plus the relatively long handle gives you some length for a little bit of light chopping (for such a small knife). My goal here is a versatile hand tool. This is why I wanted the prototypes to go to end users with experience with the original. The whole crew here has given it their .02 but I want some user feedback before we go into production.

Specs:
CPM 3V, Delta Heat treat protocol, 61 HRC, .188” thick at ricasso
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



Discussions:
https://www.bladeforums.com/threads/fk2.1642262/
https://www.bladeforums.com/threads/fk-vs-fk2.1688883/

Sales:
11/30/2018 – Testing - https://www.bladeforums.com/threads/fun-friday-sale-who-wants-to-be-a-guinea-pig.1627171/
12/7/2019 – Testing - https://www.bladeforums.com/threads/fun-friday-sale-who-wants-to-be-a-guinea-pig.1628607/
1/25/2019 - https://www.bladeforums.com/threads/sale-return-of-the-cpk-field-knives.1638543/
2/8/2019 - https://www.bladeforums.com/threads/return-of-the-cpk-field-knife-sold.1641595/
2/15/2019 - https://www.bladeforums.com/threads/sold-forty-cpk-utility-field-knife-delta-3v.1643111/
3/1/2019 - https://www.bladeforums.com/threads/forty-cpk-utility-field-knife-delta-3v.1646506/
3/15/2019 - https://www.bladeforums.com/threads/cpk-utility-field-knife-delta-3v.1649635/
3/15/2015 - https://www.bladeforums.com/threads/fun-friday-sale-edc3-and-field-knife-set.1649634/
4/19/2019 - https://www.bladeforums.com/threads/sold-50-cpk-utility-field-knife-delta-3v.1657117/
4/26/2019 - https://www.bladeforums.com/threads/sold-big-slow-sale-cpk-utility-field-knife-delta-3v.1658446/
6/14/2019 – Clean-Up - https://www.bladeforums.com/threads/sold-3-edc-and-field-knives.1667487/
11/11/2019 - Field Knife 2 pre-order, The Return of the Field Knife (2) - https://www.bladeforums.com/threads...rder-the-return-of-the-field-knife-2.1689325/
11/22/2019 - https://www.bladeforums.com/threads/the-cpk-field-knife-2-in-delta-3v-now-with-hand-grind.1696853/
1/10/2020 - https://www.bladeforums.com/threads/field-knife-2-in-delta-3v-sold.1705534/#post-19487470
1/24/2020 - https://www.bladeforums.com/threads/sold-field-knife-2-delta-3v.1708385/#post-19516940
1/24/2020 - Fun Friday sale of a one-off slicer - https://www.bladeforums.com/threads/fun-friday-sale.1708388/
2/7/2020 - https://www.bladeforums.com/threads/sold-field-knife-2-delta-3v.1711065/
2/21/2020 - https://www.bladeforums.com/threads/sold-field-knife-2-delta-3v.1713800/
3/6/2020 - https://www.bladeforums.com/threads/field-knife-2-delta-3v.1716481/
 
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AR-Trvlr

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UF – 6” Utility Fighter

Specs:
CPM 3V, Delta heat treat, tested 61 HRC, .188" at ricasso
Total length 10.8"
Blade length 6.0"
Edge length 5.6", 20 DPS
Weight 8.0 oz
Extra grippy 3D machined scales
Black oxide treated 18-8 stainless steel fasteners
The price includes a very nice Mashed Cat Kydex sheath with TecLok.

AEBL, heat treat, tested 61 HRC, .175" at ricasso
Total length 10.8"
Blade length 6.0"
Edge length 5.6", 20 DPS
Weight 8.0 oz
Extra grippy 3D machined scales
Black oxide treated 18-8 stainless steel fasteners
The price includes a very nice Mashed Cat Kydex sheath with TecLok.

Uddeholm Elmax stainless steel, tested 60 HRC, .165” at ricasso
Total length 10.8”
Blade length 6.0"
Edge length 5.6”
Weight 7.5 oz
Extra grippy 3D machined scales
Black oxide treated 18-8 stainless steel fasteners
Spec Ops Combat Master sheath



Discussions:
https://www.bladeforums.com/threads/the-carothers-6-utility-fighter.1633563/

Sales:
4/4/2014 - https://www.bladeforums.com/threads...icarta-g10-buckeye-burl-carbon-fiber.1169608/
4/11/2014 - https://www.bladeforums.com/threads/6-fighters-3v-elmax-micarta-g10-carbon-fiber.1171710/
6/13/2014 - https://www.bladeforums.com/threads/6-utility-fighters-3v-elmax-g10-cocobolo.1190778/
6/20/2014 - https://www.bladeforums.com/threads/6-utility-fighters-3v-elmax-g10-micarta-burl.1193055/
12/19/2014 - https://www.bladeforums.com/threads...ty-fighters-3v-micarta-g10-blackwood.1245737/
4/24/2015 - https://www.bladeforums.com/threads/one-6-fighter-and-five-8-shivs-3v-micarta-g10-sold.1283623/
5/8/2015 – https://www.bladeforums.com/threads/6-utility-fighter-3v-g10-sold.1287531/
6/12/2015 - https://www.bladeforums.com/threads/6-utility-fighter-3v-g10-micarta.1297543/
6/26/2015 - https://www.bladeforums.com/threads/6-utility-fighters-elmax.1301719/
8/28/2015 - https://www.bladeforums.com/threads...s-and-a-6-elmax-utility-fighter-sold.1320271/
11/30/2018 - https://www.bladeforums.com/threads/sale-6-utility-fighter.1627144/
12/7/2018 - https://www.bladeforums.com/threads/ten-6-utility-fighter.1628600/
12/21/2018 - https://www.bladeforums.com/threads/sold-ten-6-utility-fighter.1631351/
12/28/2018 - https://www.bladeforums.com/threads/ten-6-utility-fighters.1632523/
1/3/2019 – Pre-Order - https://www.bladeforums.com/threads/closed-pre-order-6-utility-fighter.1633754/
1/4/2019 - https://www.bladeforums.com/threads/ten-6-utility-fighters.1633965/
3/22/2019 - https://www.bladeforums.com/threads/sale-6-utility-fighter-in-aebl-stainless-steel.1651143/
4/5/2019 - https://www.bladeforums.com/threads/6-utility-fighter-in-aebl-stainless-steel.1654208/
7/12/2019 - https://www.bladeforums.com/threads/fun-friday-sale-aebl-6-utility-fighter.1672678/
8/9/2019 - https://www.bladeforums.com/threads/sold-ten-6-utility-fighters-delta-3v.1677929/
8/16/2019 - https://www.bladeforums.com/threads/sold-ten-6-utility-fighter-micatra-colors.1679246/
8/30/2019 - https://www.bladeforums.com/threads/sold-6-utility-fighter-micarta-colors.1681934/
8/3/2019 - https://www.bladeforums.com/threads/fun-friday-sale-opens-at-9-00-est.1681963/
 
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AR-Trvlr

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AR-Trvlr

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Scale Materials

Question re: rubber-insert scales for the choppers produced the following quote from Nathan the Machinist:
First I had to gain about 20 pounds because my old normal ass was too small for the amount of pain-in-the-ass. A full thickness sheet of micarta is skeletonized into a liner with bosses for the fasteners (can't clamp across rubber) and also solid at the front (can't kydex sheath rubber). This is run with the mounting holes complete. A rubber sheet is bonded to a standard liner to make it machinable. This is a sacrificial liner that gets cut away later. It's held down on a vacuum fixture and decked to get down to a clean bondable rubber surface and then machined to fit the skeletonized liner shape. There are hard earned tricks to machining rubber that I'm not going to share on the internet. This machined rubber is bonded to the micarta using an adhesive that ages well, will bond this kind of rubber, and doesn't loose strength with exposure to hand oils and sweat. It goes back onto the fist vacuum fixture (registered with pins) to have the mounting holes reestablished and re-machined. It then goes on to the final machining sculpting steps to be shaped into a handle, done in part with unicorn tears. Then I abuse alcohol and swear never again.

c63cc171-f87f-4aac-926d-cbd532252bf2-jpeg.1314806


Discussions:
Pictures of Different Scales in the Wild - https://www.bladeforums.com/threads/cpk-scale-options.1722353/
Antique Edge-Cut Micarta - https://www.bladeforums.com/threads/the-aecm-scales-thread.1723224/
Hard Ebonite - https://www.bladeforums.com/threads/some-thoughts-on-hard-ebonite.1638457/
Field Knife Scales - https://www.bladeforums.com/threads/field-knife-scales.1557944/
Fancy Scales - https://www.bladeforums.com/threads/fancy-scales-thread-a-cpk-picture-show.1627570/
 
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AR-Trvlr

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Screws

As of February 2021:
We have stainless, black oxide coated, matte Ti, Shiny Ti, and heat blued Ti-not anodized. Except for the swords the stand offs are 1/4" aluminum of varying lengths. The swords are 1/4" steel.

Most knives are made with black oxide treated stainless steel fasteners, but titanium fasteners have been used.

Our titanium screws are allen head now, but they used to be torx.
Nathan the Machinist said:
It is a size 8-32 flat head socket cap screw. It has a 3/32 allen socket, it is a standard 82 degrees, and it is about 5/16" head diameter. This is an ANSI standard machine screw. The ones I use are 18-8 stainless steel with a black oxide coating.

I understand people want to individualize their knives, but functionally there is no real improvement to be made in this screw. They weigh 1.1 gram, so taking weight out of them won't accomplish much, they're already much stronger than the material they're holding down, and the pins take the shear on the scales so the screws are just holding them down. They're not really a potential failure point in my view and I don't see much room for improving them functionally.

Five of six get blue locktite (removable), one of six is short (front, mark side) and gets red locktite.

Nathan the Machinist said:
I have no plans to change the construction to make it easier to take apart. In my opinion the tight pinned scales with fasteners for hold down is very effective, accurate and durable. Ease of disassembly was not a primary design driver, but when I do need to take one apart I feel the amount of effort required to do so is pretty reasonable.

Nathan the Machinist said:
The knives we make can be disassembled, but weren't intended to be. I can get them apart, but we're set up for that.

The hole diameters and pin diameters are tightly controlled and quite snug. There is very little clearance and in fact there is some tolerance overlap where pins can be a light press fit. A lot of folks can't safely deal with that.

The shorts screws found on the signature side are installed with red Loctite which is very difficult to remove. The longer screws on the other side are assembled with removable blue Loctite. When disassembling a handle you have to remove those screws and tap the pins out leaving the short screws in place. Some come right apart, some need a little help. There is .001" (half the diameter of a human hair) nominal clearance so things can be a little tight. This isn't a good project for a lot of folks, but if you're handy and have the tools it's do-able.

The holes on the tangs and the scales are located on CNC with circular interpolation then reamed to size. The location relative to each other is accurate to a fraction of a thousandths of an inch and the diameter is accurate to about a thou. The scales have some give (compared to steel) and are actually reamed a little over size because the holes shrink one or two thousandth's of an inch after reaming. The steel is reamed with a .2510 reamer, but as the tooling wears that hole can close up to .2500 before changing tooling. So, the tang hole is .250-.251, a total spread of .001".

The pins are turned here and the typical range is .2495-.2505, so there is a total spread of about one thou.

This means that some holes in the tangs can be as large as one thousandth of an inch over nominal (1/4") and some pins can be half a thou under nominal, so the pin could have as much as .0015" diametrical clearance. That's not a lot of clearance (a little less than the diameter of a human hair) but that pin will fit that hole without much effort. We try to avoid that much clearance.

On the flip side, some tang holes can be .2500" (nominal) and some pins can be as large as .2505" (half a thou over nominal) so there is half a thou interference. This is a light press fit and you have to force or tap them together. When we get into a batch with that much interference we'll usually put those pins aside and use some from another batch from the smaller end of the tolerance.

So, we aim for as close to line-to-line as we can, but accept that there are limits to the level of precision we can put into the pin/tang fit. So, some are very tight, some are less tight. All are "snug" with little or no slop. You may find yours can be removed without a lot of trouble, or you may find special tooling and techniques are required to pull yours apart. They're not made for ease of disassembly, but it's usually pretty do-able.

Nathan the Machinist said:
The sectional area of the minor diameter of an 8-32 screw is about .013" square inches. Steel screws weight about a gram. I wouldn't fool with aluminum screws.

https://www.bladeforums.com/threads/what-fasteners-are-used-in-the-lc.1407202/
https://www.bladeforums.com/threads/titanium-or-black-oxide-screws-fasteners.1615169/
 
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AR-Trvlr

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Oct 3, 2009
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Boot Dagger (with sheath by Pirtle)



Specs:
Delta 3V, HRC 60.5
Blade length 4.438" from tip to guard
Blade width .9"
Total length 8.69"
Thickness at ricasso .205"
Sharpened 20 DPS
Black on black micarta (canvas or linen)
heat darkened titanium screws
Engineered skeletonized tang
4.9 oz, balances 7/8" behind guard

Discussions:
https://www.bladeforums.com/threads/cpk-boot-daggers.1747184/

Sales:
https://www.bladeforums.com/threads/fun-friday-sale-daggers.1756451/
https://www.bladeforums.com/threads/sold-forty-4-boot-daggers-delta-3v.1757573/#post-20105146
https://www.bladeforums.com/threads/sold-20-boot-daggers.1776626/
 
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AR-Trvlr

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