Here is a little more information with some pictures of the patterns I made. I am not working on one of these sheaths right now, but the next one I make I will make sure to do a good tutorial with some pictures.
Above is a picture of the pattern pieces that I made for the sheath. The pattern is 3/8ths" wider than the knife. Trace the knife and then use a ruler to lay out 3/8ths" marks and then eyball trace to the marks to get the outside of your pattern and then cut it out. I did the back pattern (pattern to the left) first which is the longest and largest pattern. This largest one is a little short for a belt loop, I just added length for the belt loop when I cut out the leather.
Next I cut out the middle pattern which is the middle divider for the sheath. Just trace it from the first one. Notice it is a little shorter than the back or bottom piece so the back knife handle will show appropriatly.
Now cut out what will be the top cover of the sheath which is the pattern all the way to the right in the picture. Again it is a little shorter that the middle pattern so the knife handle will show the appropriate amount.
Next you will need to cut out the welts. They are pictured above depending on the thickness of your leather and the thickness of your knife you will need to cut out 3 to 4 of each. The welts will go in between the other 3 pieces you have cut out. Notice that the inside of the welt pretty much matches the contour of the blade and the outside matches the outside of the sheath. The indside of the welt should be relieved a little at the top of the blade so it will not be to tight.
Here are some close ups of the bottom, middle and top of the sheath
You should be able to see how I traced around the knives.
Once you have the patterns cut, you cut out the leather to match the pattern shapes. After this you start the glue up. first I glue the two different types of welts together, one set of matched welts 3 or 4 pieces, use barge cement and glue them together. Then the other welt the same way. I let them dry for a day.
Next I take the bottom (back) of the sheath and fold over and glue and sew the belt loop. Wet the top of the loop to ease in bending it over and forming it. if there is any tooling on the back, now is the time to do it. Also, if you are going to tool the top piece of the sheath it should be done now.
OK, now take the bottom part of the sheath the bottom matching welt and the middle part of the sheath and glue them together using barge cement. The order is bottom of the sheath, 3 or 4 welts glued together previously, middle of the sheath. Usuing this order glue them up. Let this set up and dry for a day.
And finally, we can glue up the rest. Take the remaining welt and glue it to the top of the middle piece of leather and then glue the top (front) of the sheath to this. Allow to dry for a day. This will comeplete the gluing and you will have something that looks like a rough sheath.
Now you will need to sew the sheath. I sew mine right down the middle of where the welt lays. Once this is done you clean up the outside edge of the sheath on the grinder to make it uniform and nice looking. Now you have a good looking sheath that is un-dyed.
Now take the sheath and wet it thoroughly. Now is when you work the knives into the sheath to form fit them. On these sheaths I just work the UNSHARPENED knives in and out of the sheaths while they are wet and as they dry. It takes a day to do it right. I work the knifes in and out 10 or so times each and then let them sit for an hour or so and then do it again. Once this is done let it dry all the way. Now dye it.
To dye, I wet my sheaths on the surface, this give a more uniform dying in my opinion. Don't soak them, just get the surface wet. Dye it the color you want. Once dry, seal it and you are done.
Some tips... the number of your welts are the key to retention or lack thereof. To get this right just use your best judgement. It is better to be a little tight instead of being a little loose, as the sheath wil loosen up with use.
This Once you are done you will have a nice sheath. This one that I did had no tooling since I was under a major time constraint.
Hope this helps you guys!