This is the basic process I go through when I construct a sheath from Kydex type material. In the future I hope to add photos to make this more of a tutorial, but for now I am posting this written process for people who might be interested.  Please feel free to contact me with any questions if you are confused or you think something needs clarification.

(to see a larger image, click on the picture)

First, decide if a slab (two-piece) or pouch (fold-over one piece) is best for the knife.

POUCH SHEATH

Draw a line down the center of a piece of paper or card stock (old manila folders are perfect), dividing the paper in two roughly even portions.

Lay the knife on its back (spine) with the blade edge up and the spine covering and parallel the line drawn on the paper.  Gently role the knife down so it is resting on its side.   Generally, the side of the knife that should be facing up now will be whatever side that will be away from the body when the sheath will be worn, i.e. if the sheath will be worn on the right hip, point down, blade edge back, the “right” side of the knife will be facing up on the pattern.

The line drawn on the paper should now be just visible above the spine of the knife.

Trace the outline of the blade and the handle onto the pattern paper.  It is not really necessary to trace the back of the handle or the spine of the blade, as they will hopefully be tight against the fold of the finished sheath.

Set the knife aside.

Trace a second line along the edge but spaced 5/8” from it.  This will roughly be the edge of the sheath.

Add another rough-sketched line ~1/2-1″ from the sheath edge line.  This will be the cut-out line for the Kydex.

Cut out the pattern to the cut-out line.  Leave excess around the handle area, depending on how you want to make the belt clip (a one piece belt clip integral to the sheath will require excess Kydex around the handle area, while a separate clip will require less).

Position the pattern on a sheet of the preferred color of Kydex, trace the pattern and then cut out the sheath.

Pre-heat an oven to 275-300oC.  Make sure an accurate thermometer is used, not the built-in one.

If necessary, tape off the blade of the knife, and any other parts where a tight fit is not desired, with masking or blue painters tape.  Try to do an even job as any unevenness will telescope through in the forming step and be visible in the surface of the sheath.   It is simplest to run the tape the length of each side of the blade, trimming off any excess.  Alternatively, trace an exact profile of the blade of the knife on cardstock or poster board and cut out two of these patterns.  Tape one of these patterns to each side o the blade.  These will functionally make the blade thicker than it actually is, so when the sheath, when formed the sheath will be slightly thicker than the thickness of the blade, so frictionbetween the blade and sheath will be reduced.

On the back side of the Kydex, or the inside of the sheath, trace a few index lines for positioning the knife.  Useful lines include a center line for the spine of the knife, tip location, etc.

When the oven has acclimated, place the Kydex in the oven.  Heat the Kydex until it feels like limp rubber and is floppy, usually about 5-7 minutes.

Once the Kydex is ready, remove it from the oven (cotton gloves can help).

Wrap the Kydex around the knife, being careful of the edge and noting the index marks made earlier on the inside of the Kydex.  Make sure the spine of the knife is tight against the fold in the Kydex.

Place the folded Kydex around the knife into the press base, carefully adding the upper part of the press on top.

(Go to FORMING)

SLAB SHEATH

Lay the knife in the middle of piece of paper or card stock (old manila folders are perfect).  Generally, the side of the knife that should be facing up now will be whatever side that will be away from the body when the sheath will be worn, ie. If the sheath will be worn on the right hip, point down, blade edge back, the “right” side of the knife will be facing up on the pattern.

Trace the outline of the blade and the handle onto the pattern paper.

Set the knife aside.

Trace a second line along the first line of the knife profile but spaced 5/8” from it.  This will roughly be the edge of the sheath.

Add another rough-sketched line ~1/2 from the sheath edge line.  This will be the cut-out line for the Kydex.

Cut the pattern out on the cut-out line.  Depending on how you want to make the belt clip, leave excess around the handle area (a one piece belt clip integral to the sheath will require more excess Kydex around the handle area, while a separate clip will require much less).

Position the pattern on a sheet of the preferred color of Kydex, trace the pattern and then cut out the larger back portion of the sheath.  Trace and cut out the somewhat shorter front portion of the sheath.

Pre-heat an oven to 275-300oC.  Make sure an accurate thermometer is used, not the built-in one.

If necessary, tape off the blade of the knife, and any other parts where a tight fit is not desired, with masking or blue painters tape.  Try to do an even job as any unevenness will telescope through in the forming step and be visible in the surface of the sheath.  It is simplest to run the tape the length of each side of the blade, trimming of any excess.  Alternatively, trace an exact profile of the blade of the knife on cardstock or poster board and cut out two of these patterns.  Tape one of these patterns to each side o the blade.  These will functionally make the blade thicker than it actually is, so when the sheath, when formed the sheath will be slightly thicker than the thickness of the blade, so friction between the blade and sheath will be reduced.

On the back side of the Kydex, or the inside of the sheath, trace a few index lines for positioning the knife.  Useful lines include one for the spine of the blade, tip location, etc.

If necessary, attach the drain form to the tip of the blade.

When the oven has acclimated, place both pieces of Kydex in the oven.  Heat the Kydex until it feels like limp rubber and is floppy, usually about 5-7 minutes.

Once the Kydex is ready, remove it from the oven (cotton gloves can help).

Place the large back piece of the sheath onto the base of the press, position the knife on top of that, add the front piece the sheath, check the drain form, carefully add the upper part of the press.

(Go to FORMING)

FORMING

Apply pressure, either by standing on top of the press, adding weight or hydraulic pressure.

The sheath should be cool enough to remove from the press in 10-15 minutes.  Ideally let the knife and sheath remain in the press for 20-30 minutes to insure complete cooling and forming.

Once the sheath has been removed from the press, carefully remove the knife from the sheath, being aware of the sharp edge.

Using the pattern, trace roughly where the edge of the sheath will be and cut off some of the excess with a band saw or scroll saw.

Clean out the inside of the sheath of any dust.

Using the knife, carefully test the fit and retention.  It will help to use a few clamps to simulate the rivets along the edge of the sheath.

Use a heat gun, saw, sander, etc. to adjust the fit until it seems close.

Measure and mark all rivet locations with a countersink.  A compass and ruler or dial caliper can help with rivet layout.  Don’t locate any rivets very close to the mouth of the sheath.  Placing the first rivet 1-1 ½” from the end of the handle will allow the spring of the Kydex to retain the knife but still allow ease of drawing or resheathing.

Clamp the edge of the sheath and slowly drill each rivet hole with an appropriate sized brad-point drill.  It may help to insert a few rivets in finished holes as you drill to aid in keeping the two  sides of the sheath lined up as hole are drilled.  Drill slowly and carefully, as the holes should be straight and true, and drilling fast can melt and damage the holes.  Use a countersink to hand de-bur the holes.

Finish sanding the edges, do any sculpting desired.

Polish edges with 220 grit sandpaper dry, 220 grit sandpaper wet and then a lightlydamp piece of denim cloth.  Final polish can be done with 000 steel wool with a little water, oil or WD-40 for a shiny edge.

Clean out the sheath with a dry rag.

Clamp the edge of the sheath or install a few Chicago bolts and do any final stamping or adjsutign of fit with the heat gun.

Set the rivets carefully.  Place the factory side of the rivet in the front or most visible side of the sheath.

Build or add the belt loop device.  Separate belt clips are the easiest to do (and to replace if it breaks later), but integrals can look much nicer.

This is how I build the handles on my through-tang knives.

(I am still working on the text for this tutorial, but this is a rough draft for now.)

	1.  Cut a slot in the end of the tang.  Cut a slot in a section of mild steel round stock that will mate with the slot in the tang.  I use a fiber cut-off blade mounted in a bench grinder, with a tool rest, to complete this job. You can see the rest I have clamped the blade to.  It is a section of angle iron clamped in my large vise.  It has an area cut out of it where the tang and extension meet so that the brazing can be done without the rest getting in the way, or brazing the knife to the rest.
	2.  Here you can see the two parts fitted together and ready to braze.  The two parts should fit very tightly together with very little to no gaps. I use silver brazing rod to attach the two. I usually tin the extension first, then heat the tang and extension and fit them together.
	3.  Here is the knife after brazing.  The tang can now be threaded to accept a pommel, as well as bent to whatever angle is necessary to fit the handle material.
	4.  Here you can see the stag taper, spacer materials and brass pommel has been attached and epoxied together. The pommel has a nut silver brazed to it, which threads onto the end of the tang extension, making a very solid handle, and thus a dependable knife.

This is the basic process I go through when I construct a pouch sheath. In the future I hope to add photos to make this more of a tutorial, but for now I am posting this written process for people who might be interested. This description does assume you have a basic understanding of leatherworking and sheath terminology, but feel free to contact me any questions if you are confused or you think something needs clarification.

Getting Started

1. Draw up a pattern of the sheath and belt loop on light poster-board stock. I like to use old manila folders. I currently have a large box full of folders thrown out by a high-school after the tabs got used up and bent over; a lifetime supply of pattern material. Draw only the front part of the sheath to scale, leaving plenty on the back side to be cut to fit (but lightly outline what the back part of the sheath should look like).
2. Cut out the patterns.
3. Place the patterns on the leather (in efficient locations) and trace the outlines of the patterns with a pen.
4. Cut the welt section out of the cardboard pattern and trace that onto the leather. Trace the welt a little wider toward the outside of the sheath to leave room for possible adjustment later when assembling the sheath.
5. Using a sharp knife, cut out the pieces of the sheath.
6. Moisten the leather by dunking it quickly in warm water.
7. Fold the pouch piece and check the rough fit with the knife (include the welt). Make sure the knife is wrapped in saran wrap to protect it from the moisture of the leather. Lightly work the moist leather around the ricosso and guard area with clean fingers, being careful onto mark the leather with your fingernails, but leave most of this for later.
8. When everything looks about right, gently flatten the pouch and let it dry.
9. Sand the mouth and edge of the front part of the pouch with a rough belt on a belt sander, being careful not to burn the leather.
10. If you plan to do any decorative stamping or carving, moisten the surface of the pouch with a sponge dipped in warm water and complete all stamping, decorations, etc. on the front of the sheath and around the mouth.
11. Moisten the entire pouch by dunking it in warm water, fold it over and recheck the fit with the welt and knife (wrapped in saran-wrap), using bulldog clamps if necessary. Wet-form the leather around the knife handle and guard. If more welts are needed, cut and skive them. Once the fit looks good and feels right, set the pouch aside to dry.

The Welt

1. If you are using a built-up welt of several pieces, glue all pieces of the welt together as a unit. Put the longest piece of the welt in the center and stack shorter pieces on top of or underneath it, if needed. The shorter additional welt pieces can be skived so they are angled and thicker toward the knife guard or handle but thinner toward the outside of the sheath. This way the welts will allow the leather to follow the natural curve of the sheath as it wraps around the guard and handle and is stitched at the edge. It will also keep the guard and handle from pulling the front and back panels of the sheath apart from the welt, exposing the stitch threads to the sharp edge of the knife.
2. Cut/sand the end of the welt at the mouth of the sheath with a rounded edge so the knife has a smoother entry into the pouch. Cut off enough of the other end of the welt so a drain hole will exist at the tip of the sheath when it is folded over and stitched.
3. Position the welt on the inside of the front of the pouch and check the fit with the knife. When the welt is properly located, remove it, rough up the contact areas, apply leather cement, let dry, press together, pound and clamp the welt to inside of pouch front, let dry.
4. Check knife fit again with the knife in the sheath while positioning the back piece of the pouch on the welt. When fit is good and snug, but not too tight, mark the location of welt edge on the inside of the back of pouch (ie, on the extra leather that was left on back part of pouch way back when the sheath was first traced onto the leather).

The Belt Loop

1. Position the belt loop on the back of the sheath, checking the angle of the fold so the sheath will be at the desired angle when carried, etc. and check to make sure that when the loop is stitched, the stitching that will later hold the sheath closed (and the welt in) will not be too close to the stitching that will hold the loop (i.e., allow enough space between the loop location and the edge of the pouch to allow for this stitching later). When it looks good, lightly trace into the leather the outline with a tool or dull pencil. Set the pouch part of the sheath aside.
2. Sand the belt loop edges if they need any cleaning up and then skive the parts that meet the sheath.
3. Moisten entire loop.
4. Stamp your initials/logo into loop. Alternatively, your logo may be stamped into the lower part of the back of the sheath below the belt loop.
5. Make all stitch grooves on lower and upper part of loop and any decorative stamping (ie: decorative side grooves on part of the loop that shows, etc).
6. Edge-bevel the loop making sure to not bevel the areas that contact the pouch. Edge-Kote the edges of the loop. Coat the edges of the loop with Gum-Tragacanth and let it dry; then burnish.
7. Mark stitch holes in the loop with a stitch wheel and punch stitch holes with awl.
8. Position the loop on the previously marked spot on the back of the sheath to check the location.
9. Rough up the areas of both the loop and the sheath where they will meet and then apply contact-cement with a toothpick or similar small applicator, taking great care to insure no cement will show once the loop is in place (NOTE: glue does not need to come to the very edge of where the loop and sheath meet, just very close) . Let glue dry aprox. 10 min.
10. When the glue is dry, press the loop and sheath together. Pound these areas lightly with a smooth-faced mallet to insure good glue up, and let dry.
11. Fold the lower part of the loop up and punch the upper stitch holes in the sheath by pushing the awl through holes already punched through the upper part of the loop.
12. On the inside of the sheath, connect the stitch holes with a shallow cut with the stitch-groover or swivel-knife. Make the groove where the stitch will be backstitched slightly deeper.
13. Proceed to saddle-stitch, back-stitching 2-3 stitches at start and finish and lock stitching at end of stitch. Use heavy thread when stitching the loop, seven strand.
14. Position the lower part of the loop and check fold angle again.
15. Repeat the above steps completed for the upper part of the loop.

Bringing It All Together

1. Check the fit with the knife for snugness again. When the fit is good, re-mark the location of the welt on the back of the pouch if necessary.
2. Rough up, glue, etc. the back part of the sheath to the welt. Pound the glued area from the back of the sheath and clamp it up with spring clamps to insure proper glue-up. When applying glue to the welt area it is OK to spread it a little wide to make sure the welt is well glued to the sheath.
3. Cut off excess leather on back of pouch, following profile created by welt and front of pouch. Do the same for the back part of the mouth.
4. Complete most of rough sanding of edge (welt) and mouth. Edge bevel the mouth.
5. Moisten front of pouch and make stitch groove, if not already completed.
6. Mark stitch holes and punch them with awl in the drill press rotating at slowest speed, carefully watching angle of awl hole.
7. After moistening the back of the sheath, connect the stitch holes with a groove on backside of sheath. First make a groove impression with a tool, then cut a groove with the stitch-grooving tool. Cut the groove a little deeper at the beginning and end where backstitching will be completed, and cut a groove on the front side only where the backstitch will occur.
8. Saddle-stitch the edge; back stitching at mouth and tip to reinforce these areas, starting stitch at mouth and lockstitching at the end for 2-3 stitches. Use the awl blade or other tool to work the stitch hole slightly wider so the needle and thread will go through easier for the lockstitch.
9. Pound all stitches from the back with a mallet.
10. Do any final sanding, then edge bevel side with welt and clean up any areas around mouth.
11. Edge-Kote all the edges and add some Gum-Tragacanth, let dry, and burnish.
12. Test the fit with the knife. Re-moisten sheath and form fit if needed.
13. Warm the sheath in oven at aprox. 180 degrees F and coat it with warmed waterproofing treatment. Repeat 2-3 times. Wipe off any excess if it stops soaking in. Let dry.
14. Admire your accomplishment and go show someone who might also appreciate it.