Allegedly, most plastic suppliers have it available. Minimum purchases
and other restrictions may make this unpractical for you. I’ve only
used texasknife.com for mine. Their minimum shipping charge is such that
I only place an order when I’m ready to get a number of things.
Choosing the kydex.
Kydex does come in multiple colors, patterns and textures. Precisely
what is available depends on your supplier. Black is the one most widely
available and seems to be what is most preferred. Various camoflage patterns
can purchased too, or even a carbon fiber pattern. A slightly textured
surface masks scratches and such better than a smooth surface.
Thickness is also an important consideration. Texas knife carries kydex
in .09 .08 and .06 of an inch. Thicker sheets are tougher and stronger.
Thinner sheets mold more easily and tightly. My very first attempt in
kydex was in the .08 thickness. It formed nicely and tightly. But I soon
learned that my 3/16 eyelets wouldn’t hold in two layers of that
And those eyelets were of too small a diameter for the chicago screws
of my Tek-Lok.
I ordered some .06 kydex and have worked in that for the sheaths I have
made since. With some deeper eyelets, I can also work in .08, but haven’t
yet done so again.
Reading up on the process, I learned I would need some tools. A heat
source for heating the kydex is necessary. The home oven or aheat gun]
are used a lot. Kydex stinks when it is heated. Use good ventilation.
Initial shaping of the sheet of kydex is most easily done with autility
knife/box cutter. Score the sheet well and completely, then snap along
the score, kind of like cutting glass.
To form the kydex, I’d need a . Eric Noeldechen (Normark) of On-Scene
Tactical has a 2-ton commercial press for his excellent kydex. Reading
up a bit, I found this very useful guide http://www.bladeforums.com/forums/showthread.php?t=287528&highlight=kydex+tutorial.
Knowing my taste in personal tools runs a lot smaller, I built my press
With a 12 x 12 inch square of 1/2 inchplywood board, I cut two 12 x 6
pieces. I lined that with 1 inch of foam. That meant I only needed one
piece of foam as available from Texas knife supply. You could also use
a few layers of closed cell sleeping pad foam for camping. Both work.
I attached the foam with hot glue. A spray adhesive would work well too.
That makes my press about 3 inches thick, thicker with the object in
but unclamped. With that as a guide, I picked clamps for applying pressure.
I use three clamps, two 12 inch pistol grip bar clamps and 1 four inch
C-clamp. I initially used extra C clamps but have found this lesser combination
fast and powerful. I’d use a third or fourth bar clamp if I had
them instead of the C clamp but this works and saves me money.
With the bar clamps, I can quickly apply a lot pressure to the press at
one end. Then I even out the pressure towards the other end of the press
with the C clamp.
Shaping the formed sheath can be done a few ways. I use adremel with
a reinforced cut off disk and sand paper. Normark uses a band saw. A coping
saw would also work. I haven’t heard of any specific health risks
from the dust, but protection is always smart.
Making a Sheath
You can make a kydex sheath in three basic ways: Folded over, sandwiched
For a fold-over, the knife is laid at the center of the sheet. The sheet
is folded over the knife and pressed. Every commercial or custom kydex
sheath I’ve purchased is in this style. I’ve discovered I
prefer more mounting options than this offers me. There are exceptions
For a sandwich, the knife is placed between two sheets of kydex and pressed.
For flat, the kydex is placed on a foamed press sheet, the knife then
placed on the kydex and a flat rigid board is used for the other side
of the press. This makes a sheath with one flat side and one formed side.
The flat side is simply a sheet of kydex that you attach and cut to shape
Figure out which sheath style is best for your uses and design.
Examine the knife carefully. For best results, the knife should have a
narrow spot somewhere, most often where the grip meets the guard or blade.
When you form the kydex, it will form around and behind this narrowing,
holding your knife securely in your sheath. To allow you to draw the knife,
the kydex has to be able to deform or move enough under your drawing pressure
to release the knife. This strongly influences the function of your sheath.
Too much kydex behind the narrowing, or a rivet in the wrong place and
your sheath won’t operate properly.
Trace your target knife on a sheet of paper. I usually use graph paper
as that makes measuring easy. Now, draw your desired sheath around that
tracing. Include rivets, eyelets, and screws and their offsets from edges
and the knife itself in the design.
When you form the sheath, the kydex deforms around the knife. You need
more kydex than your object is wide. Be generous. You can always trim
extra as needed but you can’t add any kydex back in.
In my small knife sheaths, I’ve found 3 inch widths sufficient
for a side of the sheath. For a fold over you’d double that, maybe
more if the object is really thick. A flat style would need more too.
If you’re frugal, you don’t want to waste too much kydex
in the project so some initial shaping of the raw kydex is in order. I
prefer the method already mentioned of scoring the kydex and snapping
it. A metal straight edge is critical in accurate shaping for making clean
straight scores. A basic rectangle is all the rough shaping I do.
For sandwich style sheaths, there’s some added concern at this
point. The two pieces when formed won’t stay together on their own
(even though some stick a bit). The better the match between these pieces,
the better the final sheath. So I rivet one end together, trying to place
it so that it forms a useful point in the sheath. This keeps the pieces
lined up all the time and simplifies some other steps as well. With a
spring clamp or two holding the pieces togehter, I drill the rivet hole
through both pieces at once. In goes the rivet and I flare it.
Heating the kydex
I prefer the oven to the heat gun. The oven has more controlled heat
and is easier to prevent overheating, at least for me. The heat gun is
Using the heat gun is mostly about developing a good motion technique
to heat the kydex evenly.
What is the risk of overheating? If kydex overheats, it becomes brittle
and shiny at even higher temperatures. Sticking is also attributed to
Heat the oven to 300 degrees Fahrenheit. Temps as high as 320 can overheat
it I’ve heard. Most ovens fluctuate 25 degrees either side of the
set temperature so there is some risk. Put the kydex in the oven. I put
it on an inverted pan or a cookie sheet. Let it heat about 10 minutes
or until limp and flexible.
Meanwhile, ready the press. Set the press plates up and ready clamps
by setting their openings to fit over the full press but clamp down quickly.
Have the knife handy as well of course.
When the kydex is ready, you have to work quickly. Remove the kydex from
the oven. The kydex is hot but doesn’t conduct heat well. A towel
or hotpad is enough to handle it.
For a fold over sheath, I fold the kydex as I remove it from the oven.
The knife is inserted and quickly clamped. This can be a bit fussy. You
may have to reheat it and press it a couple of times to get the fit you
want. When you reheat it, the kydex will unform itself. The kydex seems
to suffer from lots of reheatings. I often need two heatings and have
done a third heating on two occasions. I did more than that once. That
sheath was a failure.
For the sandwich sheath, the clamped end really helps. You don’t
have to fuss nearly as much with lining up edges. It’s easy and
tempting to center the handle by where it protrudes from the kydex. Don’t.
You want to center the blade in the sheath, not the handle. Watch your
tip too. You don’t want it too close to the rivet or off to the
side. If your sheets are sticking together as you place the blade, they
may be overheated a bit.
Similar issues would seem to apply to the flat style sheath as well.
Putting the whole knife in the press is hard on the foam, often making
tears. I prefer to leave part of the handle out of the press when possible.
Cover, and clamp it up as fast as you can. Some advocate standing on
it. That’s time consuming and any wiggles might cause problems.
I prefer the clamps. I have other things to do with my time.
Five minutes is usually enough to form the sheath, though it won’t
be cool yet. Ten minutes is better and safer.
Bar clamps tend to release a bit excitedly so be careful as they will
jump and kick a bit on release, possibly marring surfaces below, such
as your table or counter.
It’s common for the kydex to stick a some after clamping. This
isn’t automatically a sign of overheating as the pressure and residual
heat were involved.
Assess the fit and forming. Are the form lines crisp and distinct? How
are the gaps around the blade? Where two sheets meet, there is usually
a little gapping where the kydex bends together to meet. That’s
OK, but you want them fairly small. Of course, if the knife has a gaurd,
a larger gap is probably necessary to get the knife in and out.
Take some spring clamps or other clamps and approximate your eyelet placements
with them. Test the knife for retention and release. The very first test
may be tricky because the kydex may be stuck to the blade from the press.
Be careful. Adjust clamp placement until you get the retention and release
you desire. MARK the spot with PENCIL. If you don’t mark the spot,
you will not know the exact best location. This is most critical for the
eyelet closest to that narrow retention spot on the knife as was discussed
in the design steps.
If you used a Sharpie, or pen, the ink probably won’t come off.
The pencil rubs or wipes off easily so exercise care to retain your pencil
You want the edge of your eyelet flare to come to the marked point. So
mark the center point of the eyelet about 1/8-3/16 inch away from the
pencil point as appropriate for your eyelet. Use a sharpie this time as
you will drill this mark out of the sheath. With this point established,
you can fine tune the layout of the other eyelets. As I use a small TekLok,
my preferred spacing is 1 inch on center. If you need to make some layout
lines to keep things lined up, use pencil. Mark all center points for
drilling with the Sharpie.
For accurate drilling, you need to center punch each of those Sharpie
drill marks. I use a 16d nail and lightly tap a starter hole for the drill
bit tip to rest in. Otherwise, the spinning action of the drill forces
you off the precise point to drill.
The size of the hole you drill depends on the eyelet, rivet or screw
you are using. The size hole is usually specified on the package of eyelets.
When it comes time to drill, it’s best to drill both sides of the
sheath simultaneously so everything matches. The problem is that when
the drill clears the first side, the kydex on top climbs the drill bit
and forces you off the mark for the second side. Before drilling, use
spring clamps to hold the kydex together within an inch of where you are
drilling. This is another time the pre-riveted layers of kydex in a sandwich
sheath is useful.
Line the bit up in the center punched hole and drill through.
Setting the rivets or eyelets
A lot of the work of eyelets is getting the darn things in the holes
you just drilled. It’s a tight fit. I sometimes use the anvil or
flaring tool to help me get the eyelets in. It’s all still hand
pressure, but the dies seems to help on occasion. You want the eyelets
head flush with they kydex before you start to flare them.
Smaller eyelets or leather eyelets are easily set by hand with the appropriate
flaring tool and a hammer. The flaring tool is a must for the kydex. Leather
flaring tools do not work, even though the eyelets will. Flaring tools
are available from TexasKnife.com.
Leather eyelets are different from the sheath eyelets TexasKnife sells.
Leather eyelets are scored so they flare easily by hand. Kydex eyelets
are smooth and create a nicer finish, but are tougher to set by hand.
There is a special hand press available for setting eyelets and rivets.
It’s a bit pricey.
TexasKnife offers hand tool directions which are to set the anvil die
in a properly sized hole in a large piece of wood or block of metal. Set
up the sheath with the eyelet in place. Orient the flaring die and strike
with the hammer. That keeps things from bouncing all over from the impact.
For the 1/4 inch eyelets, this doesn’t work quite as well.
I’ve faked a press using the 12 inch bar clamp. I set up the anvil
and flaring die against the eyelet in the sheath. Holding the set up with
one hand, I place the clamping faces at the base of the dies and begin
clamping. Sometimes, one of the dies goes a bit crooked. The eyelet is
still set however it’s a bit rough. A repeat of the flaring process
usually smooths it out. The eyelet sets quickly and easily.
I sometimes strike set an eyelet with the dies that has a bit of a rough
finish to smooth it up.
This method seems harder overall on the finish of the eyelets than the
With the sheath now set with eyelets, return to your original paper design
and transfer the outline to the actual sheath as best you can by pencil.
Freehand works just fine.
As I mentioned earlier, I cut off the excess material with a dremel.
No matter what you use, you will probably need some relief cuts at various
points in the final shaping to free up the blade as your turn corners
and such. If you’re using a power tool for this, you need to keep
the speed on the slower side as high speed cutting melts the kydex rather
than cutting it. The melting is rather uncontrolled compared to the cutting
and better for your cutting tools too.
The edge still needs some tweaking after this and sand paper is the way
With all the cutting and sanding, it’s pretty common for some grit
to get in the sheath. Blow it out with some canned air. Don’t wash
it out as it’s hard to get all the water out.
Professional kydex has a shiny smooth edge. I haven’t seen this
discussed anywhere, but I think there’s a heat finish on this edge
besides the sanding. I noticed this effect in my heat gun experiments.
I haven’t really figured out a way to do this well, but the heat
gun is better than a lighter or other open flame.
At this point, I drill a drain hole. The tip of the knife outline in
the kydex marks the point. Use a small bit, I like 5/64”. Use a
light touch if you want the hole on one side only.
Over time, the sheath will wear and may loosen up. Using a heat gun or
blow dryer you can focus heat on the spot that needs adjusting. I prefer
the press to apply the pressure over other clamps or fingers as I’ve
distorted sheaths this way with other means of pressure.
You can custom mold pouches and clips to attach through the eyelets.
Smaller objects without a narrow spot can be held in place with friction,
though some scratching may occur.
Or you can build those in to the design with "wings" off the
basic design outline. The wings will lie flat during the initial forming
but can be heated separately with a heat gun for final molding without
damaging the sheath's shape.