Step 1: Gather Tools Prepare Area
We had most of these items on hand from other projects. The only specialty item is the 4 prong chisel from the leather supply store.
Surface to hammer and cut on
Metal straight edge
4 prong chisel or an awl
Small steel bench block
Letter stamps if monogram is desired
2 leather needles
Waxed sewing cord for leather
Scraps of tooling leather 2mm thick
Scrap of PVC pipe
Water based leather dye
Latex or rubber gloves
Step 2: Patterning and Cutting
I used the plastic zip top bag that the refractometer came in as a pattern for the front of the case, cutting a rectangle of leather the same size. The back of the case needed to be the same width and include additional length to comprise a flap. I added a narrow retainer band of leather 1/2" wider than the case to tuck the flap under. The shape of the flap followed the natural edge of the leather scrap, which was diagonal. I trimmed it slightly narrower and rounded the corners to slip under the retainer band more easily. Mark the pieces on the leather with a pencil and straight edge.
The refractometer's diameter is about 1 1/2". I went to the local hardware store to ask if I could buy a scrap of pipe, metal tubing or wood with an outside diameter of 2" and they were kind enough to just give me some PVC pipe. I had to cut it down to roughly 2" shorter than the length of the front of the case with a hacksaw.
Use your metal straight edge to guide your cuts on each piece of leather. I made several shallow cuts before going all the way through. A new, sharp blade and a slow, steady approach were very helpful.
Step 3: Stamping Holes
A 4 prong chisel makes evenly spaced holes in leather. The one I have is more for lacing than sewing, but I made do. Clamp the top leather to the bottom with bulldog clamps, clothes pins or what-have-you. Mark an eighth of an inch in from the edge of the leather on three sides, excluding the flap. Put the leather on your bench block and hammer along this line with the 4 prong chisel and rubber mallet. If you use an awl, space your holes evenly around the edges on your guide line. Hammer all layers at once, moving your clamps as needed to access your line. With a 4 prong chisel you can keep your holes even by putting one prong in the last of the four previous holes and lining the rest up on your guideline. You may need to separate the layers and tap from the back layer to enlarge the holes here and there.
Step 4: Sewing
Clamp the three pieces together with the holes aligned, rough sides together. I placed the retaining band 3/4" from the top of the front piece, rough side down, and clamped it to the other layers.
Use a piece of cord either 2 and 2/3 the length of your seam or some fraction of that, according to your tastes. It can be more comfortable to work with shorter lengths of cord, you'll just have to knot more often and hide those knots on the inside.
At this point, I held the pieces on edge, with the front to my left and the back to my right, flap pointing toward me, the bottom between my knees. I think the pros use something called a stitching pony to hold projects while sewing. If you have one, you probably don't need this Instructable!
Thread both needles on the cord, one on each end with a short tag. Be sure the thread is waxed. You can run it over a candle, in a pinch. Beeswax is nice. Poke one needle into the first hole near the top and pull through both pieces of leather until you get to the middle of the thread. A pliers will come in handy if the holes are snug. Just don't crush the eye of the needle with them. Now that I have made that mistake, you don't have to :).
With that same needle, poke through the second hole and pull the thread tight and slightly toward the first. With the second needle go through the second hole, being sure not to pierce the thread, stitching right alongside that first strand out to the opposite side. Pull both needles away from each other so the stitch is tight. Repeat with hole three, starting with the right hand needle and poking through both layers to the left. Pull tight and slightly toward hole two. Now use the left needle to poke through both layers, coming out the right side. Repeat until you have sewn three sides or run out of thread. Either way, tie the two ends of the thread together inside the case and push the knot inside. Stitch around the sides and bottom pulling tight at each stitch to keep them even, but not so tight that you wrinkle the edges.
I have no connection to this vendor, but you can get detailed sewing instructions and diagrams as well as tools and supplies at www.tandyleatherfactory.com
Don't forget to sew your retainer band near the front top. It's holes should line up with the other layers even though it is slightly wider. You need that slack to accommodate the curve of the finished case and the thickness of the flap.
Step 5: Molding
Slide the PVC pipe into the case until it is even with the top front. Pinch the leather around the pipe, and straighten the edges of the case if need be.
While the leather is damp, you can put it back onto your bench block and hammer the monogram into the flap with your letter stamps. You can be more careful than I was and gently place the stamps on the leather, rather than dropping them, and you will not have the "ghosts" of your letters on your finished case. Hold the stamps together and perpendicular to the leather and give them one good whack with the rubber mallet. More than one and they could move and cause more "ghosts". We've decided they give the piece character.
Allow the leather to dry overnight or for as long as it takes at your relative humidity.
Step 6: Dying
Pull the pipe out of the case and the leather will hold this shape.
Put on rubber gloves, unless you like perma-tan and the look of filthy nails. Apply the dye with a rag, rub it in and buff off the excess with a clean rag. Attend to the edges and the margins around the stitches, being equally thorough in the application of the dye in these areas as in removal of the excess.