The Dwarven Folding Knife of Secrets and Friendship

Recently I've enjoyed adventure hiking - hiking in a cloak and pirate hat, or bivvying with just a tarp up the side of a mountain, or organising a trip with my friends to remove wilding pines (pine trees are a pest in native New Zealand forest) and build shelters from them. While doing some research for a future adventure hike, I came across the Middle Earth Reenactment Society, (those guys are hardcore) and while watching one of their youtube videos spotted a very nice "dwarven friction folding knife" - which I liked the design of. Rather than copy it exactly, I decided to do my own take on it. This project was done over a couple lunch breaks and evenings while working from home.

There are some things I would do differently if I were to make it again, so have a read through of the mistakes I made so you don't have to make the same ones.

Materials

• ~3mm thick Annealed Carbon Steel (I used some 1084)
• ~1.5mm steel sheet (I used some galvanised pipe I cut up, see step 2)
• 3mm Brass Rod
• 1mm Copper Sheet

Tools/Supplies

Metalworking

• Hammer with a ball/rounded end
• Hacksaw
• File
• Vise
• Propane Torch
• Whetstone
• Pliers
• Drill and drill bits
• Angle Grinder, Belt Sander, and/or bench grinder will make things a lot faster, but if you want to be more period correct you don't have to use them.
• Sandpaper

Etching

• Vinegar
• Power Supply
• Q-tip
• Nail Polish
• Scriber
• Wire

The original knife was made by Petr Gullinbursti (youtube, website) and weaponry and I found it in this video by the Middle Earth Reenactment Society. He definitely deserves the title of master craftsmen, his work is absolutely beautiful.

I've attached screenshots here just in case those links go dead, but I explicitly didn't want to copy it, so after seeing it, I then put the video down, went to work, and in the evening when it had faded from my mind, started to think about how to build it. I ended up with the plan shown. You can adjust the size to suit your hands - The handle of mine is ~9cm long.

In my mind the dwarves are a functional, practical lot. They mine, they smith, they explore, they build. As a result I've always had their asthetic as largely functional. There would be a small amount of decoration, but compared to the much more lavishly artistic elves, dwarven items are quite plain. As a result I built this to look a little old and used. In my mind this knife was made by a dwarf using left-overs from his normal work, he found small scraps of metal that would work for the job, and built it because he needed it.

Source the material

I didn't have any 1.5mm steel sheet, but I did have some 19mm galvanized pipe with 1.2mm wall thickness. So the first order of business was to cut and flatten it. Since I only needed 20cm, cutting it lengthwise in a single place was achievable with a hacksaw. I could then use a screwdrive to lever it open and hammer it flat on my anvil (milled-surface double-thickness railroad track. That thing deserves it's own instructable at some stage).

The metal was galvanised, but I stripped off the galvanising by leaving it for a couple hours in a pot of vinegar (not photographed).

Cut Roughly to Shape

Mark out the handle design using a scriber, and using a hacksaw or angle grinder or tinsnips, cut it to shape.

Bend

Find something to bend it around (eg a chainsaw file, a piece of stiff 3mm), and bend the handle into a "u" shape.

Finish Shaping

Finish off shaping the handle using a belt grinder (or files) to make it symmetric.

Although it may seem easy to drill the holes during this step, I'd advise waiting until you've got all the parts. By waiting you can ensure everything will line up.

Cut out the rough shape

Find yourself some steel that is the right size. Draw on the shape of the blade, and cut it out with an angle grinder (or a hacksaw if your steel is annealed and you have more patience than me). Leave a bit of extra space.

I use metal-cutting diamond blades on my angle grinder rather than cutoff disks. They have a slightly thicker kerf, but produce less dust, you don't risk them breaking, and they last for a very very long time.

Refine the Profile

Using a grinding disk in the angle grinder, continue to develop the profile until it is what you want. If you have a belt grinder, use that to finish off. By the end of this, it should look exactly like the blade you want when viewed from the side.

Bend the tag

Before bending the tag, put a slight chamfer on (what will become) the inside of the loop. You can see this in one of the photos. When the tag is bent around it will be very hard to do any shaping work inside the hole, so you can do that before bending.

Similar to bending the handle, find a round thing and bend the tag around it. I used the aluminium jaws of my vice and a hammer to do the bending, this avoids bite marks that you'd get from a pair of pliers

As you bent the tag around, it would have made the metal slightly thicker on the inside of the loop. This would cause the blade to jam open, so using a hammer and belt grinder (or files or sandpaper), flatten off the ring so that it is the same thickness as the rest of the blade.

I ended up doing this step twice because I ended up not happy with how long the first tag was (it was too long). So if you notice two variations, yep, your eyes do not deceive you.

Clamp

Clamp the handle and blade together in the open position, making sure that everything lines up. In particular look at where the loop is. It should be flush with the handle.

Drill

Now you can centerpunch and drill a 3mm hole through both the handle and the blade. Because you've done this with everything in the open position, you know the hole will line up in all the parts, and that the blade won't be able to over-open (once the s-ring is made).

I use an angle grinder for this, but if this is the first knife you've made, I'd suggest being quite gentle with it - you can remove a lot of material. Draw some lines in pen where you want the grind to go, and then try to grind a flat surface between those lines. Generally this is a lot "shallower" than you'd expect and you'll feel like you're grinding on the surface.

After the initial pass with the angle grinder, I then cleaned it up with the belt sander and some hand filing to get the start of the grind nice and square/in-line.

You don't need to take it all the way to sharp at this point, wait until after tempering.

At this point I heat-treated the blade, but this led to me having to work around it being heat treated later, so the photos show a more complete knife, but I'd advise not pinning things together quite yet.

The knife is prevented from over-opening by a s-shaped ring through the tag. You want this to be a reasonably tight fit, but it should still be able to rotate freely. I used an offcut from when shaping the blade, and ground it down until it fit nicely through the hole.

I then bent it into the S-shape using a vice and hammer, finishing it off by hammering it closed around the loop.

Temper

While I have a forge, for a blade this small it is much quicker to use a propane torch and a couple fire bricks. This reduces the heating time to probably a minute or so from dead cold.

My steel was 1084, so it was a simple case of heating to red (not orange or yellow), and quenching it in some water. This leaves the steel hard but brittle, so after cleaning off the scale with a wire brush, the metal was tempered. The proper way to do this is with an oven (or even more properly a kiln), but I was lazy and just waved the spine of the blade gently in-front of the propane torch a bit, judging it's heat by how it changed color as it got warmer. Very non-precise, but good enough for me.

There are plenty of resources on how to temper steel, so either have a read of those, or just play around with some scrap steel - trying to bend and snap various levels of quench/temper/anneal.

Clean

Clean it up using a wire brush. I have one mounted in my bench-grinder, so if you're careful that makes things really quick. Otherwise a wire brush by hand (or even a scouring pad) works OK.

Making Copper Washers

I wanted some square copper washers, so I drilled some hole in some 1mm copper sheet, and then cut around them with tin-snips. I then clipped the corners (to make them octagonal) and sanded all the edges. Voila, square copper washers.

Brass Rivets

Brass pin rivets are quite easy to do: cut a length of brass rod slightly longer than what you want, slip it all together and then hammer on a hard surface it with a ball hammer. A ball hammer has a rounded end which means that instead of compressing the rod (and making it thicker) it will tend to mushroom the rod - turning it into a rivet. You want to hit all over the rivet so that it domes nicely. Also make sure to both rotate and flip over the knife regularly so that it stays symmetric.

Oh no! It's too tight

Can't move it by hand? That's OK, you can both tighten and loosen a pin rivet with a hammer. If you hammer the rivet on a hard surface it will make the pin more stiff. If you hammer it when it is over a hole it will make it looser (see picture as for how this works). I recommend hammering it into the shape you want first, and then loosening it as needed.

I did attempt to make a hollow punch to improve the shape of my rivets, but it didn't work how I expected. You can see in the last picture how it left a ring around the rivet. If I were to make another one I wouldn't bother with this

To do the etching I needed to come up with some symbols to etch. I browsed around some celtic designs, and came across one that someone claimed represented friendship. I like the shape it had and thought it would go nicely on the blade.

Then, because this is a dwarven knife I wanted a dwarven symbol. The good old internet provided some in the form of the @striving-artist, who came up with some ideograms.

Prep

Prep the surface for etching. For me this was just wire-brushing it, but you could get solvents involved I suppose.

Etch Resist

I used nail varnish as an etch resist, and put down a coating around where I wanted the designs. I then used a hot-air-gun to try dry it faster. I then used a scriber to cut through the resist where I wanted the designs.

A very similar process has been done since days of old - often using wax as the resist material

Electro Etching

I used a 12V 3A power supply for this, but you can use just about anything with more than a few volts. 9V batteries are common (but expensive). Heck, strip the wires from a USB cord and use that.

Wrap the positive wires around the Q-tip and dunk it in some vinegar. You can then slowly dab the Q-tip around and it will slowly eat away at the metal. I reckon deeper etches look better, so take your time, and practice on some scrap if you want to be scientific. I just went for it.

This is not particularly historically accurate. More historically accurate would be to use a strong acid, but I have a dislike for having harsh chemicals lying around, so went for electro etching instead.

Remove the Resist

Nail polish dissolves in acetone, so a quick wipe will remove it when you're done.

There are whole instructables on this process, so go check those out if you need more detail, otherwise just go for it and try! It's really not that hard.

I didn't like the super-bright look of the clean metal, so decided to patina it. This was very simple and consisted of leaving the blade in some vinegar for a couple hours. After removing it from the vinegar bath, I neutralised the vinegar with some baking soda. This leaves the surface matt, and darkens the engraving nicely.

Annoyingly this only patina'd the steel, not the copper or brass. I'd need something different to patina the copper, so I just left it as-is for now. It'll patina by itself over the next couple weeks.

I then coated the entire knife with some cooking oil to help prevent the blade from

Sharpen

If you had sharpened it before soaking it in vinegar, well, it wont be sharp any more. So break out the stone and touch up that edge until it's nice and sharp.

Done

This whole project only took ~5-6 hours total, and was a fun few lunchtimes. I've got enough steel to do a bunch more in a similar design and am very tempted to do so - but I've also got a whole stack of other projects competing for my free time....

Hopefully this inspired you to have your own go at making a friction folding knife. I really like the design of this one as it is simple to build, can't over-open, and doesn't require much precision to build (unlike most folding knives)

If you have any questions or things you think i should add/clarify, let me know and I'll update the instructable.

Oh, and final fun fact? What's the plural of dwarf? Dwarves? Well, the older form is for cooler: Dwarrow