Improvised "survival" field sharpening

[Sacamuelas]

Had an idea for a thread when reading the Reaper's survival thread in the Fieldcraft forum. We have had a thread that covers proper sharpening technique with purchased/issued stones,diamonds, etc. We did not deal with the issue of a scenario where you need to sharpen your survival knife when you do not have access to your favorite method/material.

I will start it off with some info I found on the subject:

Rocks are usually the first thing that comes to mind. One of the best I’ve found for sharpening is sandstone and hard mud-rock - a layered material that couldn’t make its mind up geologically whether to be mud or rock. These materials are usually found in canyons, mountainsides, and river cuts. Even if your area has no sandstone, weathered granite and igneous rock out-croppings that have become ‘rotten’ will suffice.

Processing this into a usable sharpening stone takes some work. Begin by taking two pieces and rubbing them together to produce a flat surface and remove any projections that may damage the blade. This process is helped along by adding water since it keeps the surface clean, thus assisting the break down process.

Once you have a flat surface, a blade can be sharpened by applying water and stroking the edge along the prepared surface. Thin flexible blades, such as machetes, work better and sharpen quicker than rigid blades. These large, thin blades naturally follow the stone due to flex while the bigger gripping surface gives the sharpener more control.

A back and forth sharpening motion, cutting in both directions, seemed to work quicker and provide better results. Another tip when sharpening dull pieces is to allow the silt formed from the water and sharpening process to remain on the rock. This silt contains minuscule abrasives that increase the cutting action.

Using creek bed stones for primary sharpening is not a good idea since they’re usually too tightly bonded to provide efficient break down, however the smooth surfaces on these stones work well for polishing or touching up an edge.

One of my favorite primitive sharpening techniques requires no rocks. Find a small hardwood sapling about 3 inches in diameter and split it in two with your knife. Smooth the heartwood side down until you have a good flat surface. Take the point of your knife and make multiple small holes in the flat surface, then grind in a pasty mixture of sand and water.

These improvised hones are slow but eventually become saturated with the gritty material and provide a decent pocket hone capable of touching up the edge of your blade. One thing to remember with this process is to stroke away from the blade so you don’t gouge the wood. Any wire edges produced can be removed on a strop or smooth rock. These sharpening devices take some time to ‘wear in’ but are really useful when nothing else is available.

Sharpening serrations in the wilds is difficult but can be done using the edge of a soft rock. Break the rock to produce a sharp edge and then rub these edges into a radius with the piece of stone that broke off. The rounded portion of the stone is then used to stroke the serrations. Smooth edges found on creek bed stones can also be used to polish and lap serrations.

For fine touch-up in the wilderness nothing’s better than a belt or pack strap with some sand or mud rubbed in. This strop, and added abrasive, will quickly restore a keen edge on a blade that only needs minor adjustments. Instead of pushing the blade into the sharpener as you do with stones or hones, on a strop you want to move the cutting edge away from the strop. This does not remove metal but polishes the existing edge.


Any other improvised methods to share? Do you have a better or more effective method than those described above?

[Bill Harsey]

Great thread and good information! I would like to argue that serrations can best be field sharpened from the backside only. Treat them just like one side of a regular knife blade. I've done this before many times...this isn't theory.

[Sacamuelas]

Originally posted by Bill Harsey
I would like to argue that serrations can best be field sharpened from the backside only.

Okay.. You Win.
I'll take your word and experience, Sir.

[The Reaper]

Top edge of a car or truck window.

TR

[Ambush Master]

Originally posted by The Reaper
Top edge of a car or truck window.

TR

Also, the bottom of "Ceramic" Cups, as in Coffee. They have an "Unglazed" ring on the bottom.

[Bill Harsey]

Both the window and coffee cup sharpeners are very good thinking. I should make a video of this someday, using the coffee cup first then the top of a car window to bring back an edge in the field. I'm waiting for Reaper to figure out how to do this with explosives.

[The Reaper]

First, you harden the metal, then I shoot a fairly thin sheet explosive like Flex-X or Deta-Sheet on it.

The fractures are jagged, but very sharp!

We could try using a linear flexible shaped charge like Jet-Axe to try to blast the edge back into sharpness, but I have my doubts about the usability of the edge.

TR

[Ambush Master]

Originally posted by Bill Harsey
Both the window and coffee cup sharpeners are very good thinking. I should make a video of this someday, using the coffee cup first then the top of a car window to bring back an edge in the field. I'm waiting for Reaper to figure out how to do this with explosives.

Once you find it, and it's cooled down enough to handle, a "Spark Plug" insulator is basically the same material as a "Crock-Stick" .

Coffe Cup or Spark Plug = quality Ceramic that will eat at steel.

Later
Martin

[Bill Harsey]

I never should have brought up the explosives, I knew he'd figure it out. Can't take him anywhere. I'll try out a spark plug in the morning (when I'm back out in the shop). Sometimes I keep my eye out for river rocks that are both smooth enough but have enough tooth to the surface to try to sharpen a knife with. I will start asking my knifemaking friends about this topic, many heads better than one with the exchange of good information being the goal here.

[G Wheeler II]

Also think about all the blasted/broken shitter tanks and ceramic tiles you find, in most any built up area. The inside or unglazed areas large or small work well for a field exp hone/stone and a large chunk will work for a whole team and is easy to afix it to a central area for all to use. Just remember to work it smoth first before you use it on your knife.


"Turn Left Damit"