So...where I am we had a crazy wind storm, causing a power outage. The power outage was finished within a few hours, but the resulting power surge fried my router. So, for a few days I had no internet, until I could get a new one shipped out to me.

At the same time, my Sister in Law came to town to visit. In her belongings was a single throwing knife, without a sheath. So, I decided to make one for her and build it in 1 hour. I managed to put in the last of the stitches just as my hour ran out.

Supplies

Leather

Tools

Leather Stitching Needles (At least 2)
Waxed Linen Thread
Ruler
Leather Groover
Awl
Razor Blade (Mine is in that black razor blade holder) or other cutting tool
Small spring clamps with leather pads (The tiny tiny ones that you see at hardware stores for like 39 cents; these have little leather pads on the ends to prevent them from denting the leather)
Stitching Pony (Not pictured. This isn't strictly required, but it does make the stitching a whole lot easier)

Step 1: Cut Out the Back Piece

The first thing to do is to mark the pieces of leather for cutting. I used some light brown leather that I received from a Remants bag that I bought at a local craft store.

I traced out the shape of the blade with some chalk, sharpened to a point. I kept this first piece slightly larger than the blade itself, to give myself room for stitching. I made most of the measurements by eye rather than using a ruler, and tried to keep somewhere between a 1/4" and 1/2" of extra material around the blade.

At first, I tried to use my handy Exacto Knife to cut the leather, but I found that a single-edged razor blade in a holder (I have the Outdoor Edge Sidewinder) made much better cuts.

Once I cut out that piece, I used my little spring clamps to fold it in half to see if I could make the whole pattern more symmetrical. It actually worked fairly well.

Step 2: Cut Out the Front Piece

So, after cutting out the back piece, I used it as a pattern to cut out the other piece of leather that would be on the front.

Since this piece didn't need to cover the whole knife, just the blade itself, I marked it and cut it off at at point near the end of the sharp blade.

Step 3: Grooving and Preparation for Stitching

I use a specialized leatherworking tool called a Leather Groover to cut out a small channel near the edges of the leather pieces in preparation for stitching. This groove helps protect the stitching and gives an easy line to follow for stitching.

Don't have a groover? Don't worry about it. It's nice, but not entirely necessary.

As well, at this point, you should use an awl or diamond chisel to punch the holes for stitching. I usually put a piece of cardboard underneath the leather so the awl doesn't go into my desk or self-healing mat. Me, being in a hurry, decided to try and skip this to get straight into stitching. After realizing that this wasn't going to work, I pulled it out of the clamp and made the holes with an awl.

Step 4: Stitching

So, now comes the stitching. This step takes up the majority of the time of the project.

I use a saddle stitch on leather, which requires two needles on each side of a piece of thread. I use a stitching pony for this to make it easier, but you can go without one if you need to.

Clamp the pieces of leather into the correct position on one side so you can easily position it in the stitching pony. Saddle stitching isn't too complicated, but instead of teaching you here, I would refer you to jessyratfink's Saddle Stitching instructable.

Stitching takes a while and requires patience, but, after a whole lot of it, you will have a new knife sheath.

Here are a few instructables on how to saddle stitch and how to build a stitching pony. As well, if you are looking for more information on Leatherworking, the user jessyratfink has a ton of other instructables featuring the basics of Leatherworking.

Step 5: Finishing Up

After a bit of minor cutting (just cutting off some sharper pieces of the leather), I sheathed the knife and called the sheath done. I originally wanted to add a strap with a snap, but I ran out of time, as stitching took a little longer than I expected. But, even without the strap, the knife is a tight fit in the sheath and is perfectly functional.

My Sister in Law left a few days ago and has enjoyed being able to carry her knife in her purse without stabbing into any of her other belongings.