To Make a Scabbard for an SCA Rapier
Good scabbards for SCA rapiers are also pretty rare. This is how I make mine. Basically it's a leather cylinder (because SCA rapier blades aren't flat, like their historical counterparts.)
Start by measuring the circumference of the tip of the weapon you're working with.
Cut a strip of leather that's 1/2 to 1 inch wider than that circumference, and a couple of inches longer than your blade.
As a rule, you'll want something fairly stiff, at least 8 or 10 ounce leather. Alternatively, you can use a piece of PVC pipe inside the leather (I had to start doing this when I began using a Del Tin blade, because otherwise the balance was off and it wouldn't hang right.) If you're using the pipe, make sure it's longer than the blade, and that the leather cover is longer than both of them--the leather tends to shrink during while being worked, and it's much easier to trim a bit off the end than to have to re-do the entire scabbard because you underestimated.
Punch or drill holes along both long edges, spaced 1/4 inch apart.
If you want to dye the leather, do so at this point. You could probably tool it too, if your fancy runs that way. If you prefer the natural leather look, proceed to the next step.
Once the dye has thoroughly dried, soak the strip of leather in water so it's soft and pliable.
Start at one end and roll it into a tube so the long edges meet. Sew the edges together. The inside stitches should run lengthways, so they won't be cut by the blade sliding in and out of the scabbard.
The outside stitches go across the seam. I'm using red thread here for greater visibility; the actual stitching will be done with black thread.
While the wet leather is fairly pliable, once it dries, it will maintain its new shape.
6. To finish off the end, squeeze the tube together and cut it off into a curve or fairly blunt point. Punch a few more holes and sew the end together "wrong side" to "wrong side".
There are a couple of options for making the hanger. Historically, scabbards were hung from some sort of hook off of a ring on the belt. There are several nice pictures here: http://www.karlrobinson.co.uk/Gallery_hangers.html
1. The "quick and dirty" method is to cut an elongated "D" shape--at least six inches by twelve. Wrap the end around the top of the scabbard and sew it to itself. Mount some kind of hook at the apex of the curve.
2. A more elaborate and historically accurate method is to make the "D" from a long piece of leather, folded over on the sword side. That edge is cut into a series of loops which slide over the scabbard. The "buckles" are sliders that are used to give a friction-fit on the scabbard. To make the sliders, get several small buckles from Tandy (or wherever) remove the tongues and slide them up the loops before inserting the scabbard, rhen slide the loops down toward the scabbard to hold it in place.