Adding a choil to the spine (BK2)

[woofie]

Generally new to knives. Just got my first real knife, a KA-BAR BK2. It'll mostly be on camp duty; processing wood and hanging around the fire pit. I'd like to add a choil to the spine for 1/2" ferro rods. This means removing a bit of coating and the actual blade modification. I have zero experience with either but also handy with power tools, after some research (and tool rental).

All that being said, would you all recommend doing this myself (if so, how) or should I send my BK2 off to someone (if so, who)?

 

[Darkpast]

do it yourself, make it yours.

 

[scdub]

Don’t do it.

You bought a BK 2 because it’s extremely durable - why make it LESS durable by adding a stress riser to it.

I’d recommend just making a sharp 90 degree spine (or section of spine).

This will spark ferro-rods just as well as a “choil”, and will also be a nice additional edge for scraping and smoothing wood.

Oh - and I just saw this was your first post - welcome to the forum!!

BTW: All you need for a 90 degree spine is a very flat surface and a few grits of wet/dry sandpaper. Just lay the spine on the wet (I’d use oil) sandpaper, which is stuck to the flat surface (piece of glass or flat marble, etc) with surface tension of the oil (or water), with the tip pointing away from you and the edge facing the sky. Starting with the lowest grit (~120/220) drag the knife towards yourself using fairly light pressure until you sand away the coating and get a sharp spine. Repeat with finer grits until you’re happy. Add paint as necessary for screw-ups and scrape away.

 

[elasmonut]

If you're lookin for choils...look no further than a Strider made knife!
Pick the right model and you can have more choils than cutting edge I think some even have choils in the handle !!
Personally I would trade the ferro rod for a bic lighter.

 

[eveled]

The edge of the knife will work to throw a spark. To me a ferro rod is an emergency backup. So I dont mind relying on using the edge in an emergency. For practice use a striker

 

[sodak]

I make mine with a dremel, just have a bucket of water handy to dunk the knife in from time to time.

 

[woofie]

Don’t do it.

You bought a BK 2 because it’s extremely durable - why make it LESS durable by adding a stress riser to it.

I’d recommend just making a sharp 90 degree spine (or section of spine).

This will spark ferro-rods just as well as a “choil”, and will also be a nice additional edge for scraping and smoothing wood.

Oh - and I just saw this was your first post - welcome to the forum!!

BTW: All you need for a 90 degree spine is a very flat surface and a few grits of wet/dry sandpaper. Just lay the spine on the wet (I’d use oil) sandpaper, which is stuck to the flat surface (piece of glass or flat marble, etc) with surface tension of the oil (or water), with the tip pointing away from you and the edge facing the sky. Starting with the lowest grit (~120/220) drag the knife towards yourself using fairly light pressure until you sand away the coating and get a sharp spine. Repeat with finer grits until you’re happy. Add paint as necessary for screw-ups and scrape away.

I like the look of the spine choil and assumed the durability of the knife would not be meaningfully compromised. But I'd be ok with a sharp spine. Is there a method for sharpening a small, ~1" section of the spine versus the whole shebang?

 

[woofie]

The edge of the knife will work to throw a spark. To me a ferro rod is an emergency backup. So I dont mind relying on using the edge in an emergency. For practice use a striker

Not on the BK2. At least stock. The coating is too thick and rounds the edges. I'd have to sharpen the spine.

 

[scdub]

I like the look of the spine choil and assumed the durability of the knife would not be meaningfully compromised. But I'd be ok with a sharp spine. Is there a method for sharpening a small, ~1" section of the spine versus the whole shebang?

Yeah just use some strong duct tape to cover the areas you don’t want to grind.

And no on a knife that thick it probably wouldn’t cause a break, but it COULD. If you like the look however go for it - just don’t make it too deep…

 

[EngrSorenson]

If you absolutely feel you must put in some kind of "choil" cut out feature, keep the radius as large as possible and you'll reduce the stress concentration.
Personally I wouldn't modify it at all, and just use a striker for ferro rods, but do what makes you happy.
The great thing about the BK2 is that they're not super expensive to replace.

Not on the BK2. At least stock. The coating is too thick and rounds the edges. I'd have to sharpen the spine.

He means use the literal edge of the blade- personally I like his advice.
I prefer to keep the spine of my knives rounded so I don't have to avoid sharp areas when I'm using the knife.

 

[Guy McVer]

Personally I would trade the ferro rod for a bic lighter.

Why trade when you can easily carry both without issues? Always have a backup fire source. There's a lot of different ways to carry a ferrocerium rod, so you can also have multiples of those too if you want.

 

[eveled]

Not on the BK2. At least stock. The coating is too thick and rounds the edges. I'd have to sharpen the spine.

I was talking about the actual cutting edge.

 

[killgar]

I can't help but think that it would be easier, and cheaper, to just carry a small piece of steel to use with the ferro rod.

Grinding an edge (or a choil) into a HARDENED piece of steel isn't the most difficult job, but it's not the simplest either. There are basically two ways to do it-

1. Use files. Likely diamond files would be needed. This would require the purchase of files (if you don't already have the proper ones), and it would take several hours.

2. Some sort of power tools. And one wrong move using a power tool on your knife and you might end up regretting the attempt.

And if you send it out to have a professional do it, then you have to pay for the work, pay the shipping both ways, and hope the guy doing the work doesn't experience any "issues" (family emergency, health problems, etc) while he has your knife.

Back in my camping/backpacking days I just carried a little shank of steel. It was so small and easy to carry I never noticed I had it.

As far as "Why carry/use a ferro rod instead of XYZ?". Because they're fun. The "primitiveness" of it has an appeal (like camping itself), and it adds a little challenge to fire making. As a child, when I used to go on camping trips with my friends and their families us kids would have fire-starting competitions with our "flint and steel". We took pride in our wilderness survival skills. Lots of fun, good memories .

 

[Guy McVer]

I can't help but think that it would be easier, and cheaper, to just carry a small piece of steel to use with the ferro rod.

Back in my camping/backpacking days I just carried a little shank of steel. It was so small and easy to carry I never noticed I had it.

Any sharp corner or edge will be able to produce sparks from a ferro rod. You could use use a piece of broken glass if you had to, and it would work. You don't need to use steel unless you're trying to get sparks from striking a piece of flint or quartz. In that case you would need carbon steel.

Rough textures also work for producing sparks from a ferro rod, like a file.

With this in mind, it's possible that you may already have something that would work as a striker so that you don't have to carry a dedicated one. A piece of carbide on a pocket knife sharpener would also work as a striker, for example.

Did you know that the inside of a wire notch on a victorinox SAK will spark a firefly ferro rod? I've done it myself several times on 58mm, 84mm, and 91mm models. I think it works because the inside of the wire notch is rough so that it is able to grab onto wire housing better.

 

[Enzo’s Woodshop]

Some good advice here.

Yes, putting a big choil in the spine of a BK2 will noticeably reduce its strength. If you want to strike a rod with your knife, add a honed section of 90° edge to the spine. It’s way easier than making a choil and it won’t compromise the knife’s strength.

I’ve put my BK2 through extremely hard use. It’s a good tough knife, and will do anything you ask of it. Keep that in mind when considering potential modifications. The purpose of the BK2 is to be strong, diminishing its strength basically reduces its main purpose.

Whatever you end up doing with yours, I hope it serves you well.

While we’re on the topic, here’s my BK2 doing some harder tasks. While it’s not my strongest knife, it’s easily stronger than I’ve ever needed a knife to be.

I put some custom scales on mine and got a nice sheath.