Making a Kydex Sheath (step-by-step)

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Xplorer
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Making a Kydex Sheath (step-by-step)

#1

Post by Xplorer »

Hello again!!

With the handle finished the knife is more usable now, but it's still hard to leave the house with it until I have a sheath. So, now I'll spend about 2 hours and make a Kydex sheath for the Mule.

I'm going to take you with me for each step I take while I make this one. There's a lot of ways to do most of the steps involved here. There's also a lot of design possibilities. This post will show you the steps I took to make a simple folded sheath. I chose to do a folded sheath for 2 reasons. Folded sheaths are more compact. Also, folded sheaths are more difficult to mold than 2-piece pancakes. In demonstrating a folded sheath you will see the challenges that arise with this style and still learn everything you need to know if you want to do a 2 piece sheath.

Step 1 - cut a hole in a box...no wait that's an SNL skit :p , first step here is to choose the Kydex (Holstex in this case) for the sheath.
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Then I want to cut out the piece I will need. I leave myself plenty of extra material top, bottom and to the eyelet side when I measure out the piece to cut.
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You can score the Kydex/Hostex with a razor blade. Once you've cut about half way through you can fold it back and forth to break off the piece.
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Now I want to add some thickness to the blade so that the sheath is not overly tight. I apply 2 layers of clear packing tape to the blade on each side. I'm careful to apply the tape evenly and only up to the plunge line. I do not any play from the ricasso up through the handle...only a little space for the blade itself to be able to enter and exit without unwanted friction.
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I then trim the tape carefully.
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If you want water to drain out below the tip you can add a drain hole now. I taped a piece of brass rod on the end this time. Almost anything the right diameter will work. (NOTE..later I re-made this sheath and ultimately used a smaller diameter than pictured here) . The other option for drain hole(s) is to drill a hole or holes in the sheath later.
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Heating the Kydex -

There are a lot of way to accomplish this. I simply use an old toaster oven (that I had intended to throw away a few years ago). You can use a kiln, a kitchen oven, a heat gun, or anything that will get it hot. IF you choose to use your kitchen oven I need to warn you that Kydex stinks when it's hot. If you are particularly sensitive to odors or married, you might want to think twice before you use your kitchen oven.

I have a mark on my toaster oven for Holstex. It's set at about 390F(ish). Anywhere in that general temp range will do.
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When you first put the kydex in the oven there's a white strip along the side from where it was cut. You can watch this as a way to know when you've achieved the right temp.
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As it heats you'll see the white strip start to melt back into the correct color. You can see in the pic below that there's only a little white left directly over the metal bars that are not quite as hot as the radiant heat in the gaps.
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After about 90 seconds the heat has fully saturated the material and the side should look like the rest of the sheet. You can see that it's just beginning to slump a little in the corners.
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I wait 60 to 90 more seconds and let it get "floppy" before I take it out of the oven. At this point it's not too hot to hold gently but it IS definitely too hot to squeeze it in my hand. It's a little difficult to fold around the knife and position because it's hot at this point. This is good. You want it hot, and you want to get it on the knife and under pressure now ASAP. The faster you can get it under pressure the better you're overall molding detail will be.
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In order to make sure I get things set as quickly as possible, I have everything set up and ready. My oven is mounted above the press, the press is open, the foam is ready, the knife is sitting as I want it to sit when I add the Kydex.
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Pressing (Molding) the Kydex -

There are a number of ways to do the molding. The main thing you need is molding foam. You can get it from many knife making supply and sheath making supply companies on-line. I've posted links for this foam in other threads in this forum but if you need help finding the right foam just let me know.

You can get creative with how to press your foam. One inexpensive way many people can do it is to use a bench vise and a couple of 1x6x12 boards to squeeze your foam. If you have any sort of manual press (1/2 ton or more) you can use that as well. You could build a press in about 2 hours out of plywood and door hinges like I did. You can buy a nice all-metal press from knife making supply companies if you want to spend the money as well. If you're a total bad-a$$ you could even build yourself a sweet vacuum molding system (if you can do that, you don't need to be reading anything in this post :cool: ).

Back to the process -
I wrapped the hot kydex around the knife, covered it with the top foam and shut the press. I immediately applied pressure with some quick clamps.
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I then quickly added C-clamps to really squeeze it. The quick clamps are great but they don't provide anywhere near as much pressure as real clamps.
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After 10 minutes in the press I release the pressure and check it out.
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At this point it's still a little hot and it's important to be careful not to mess up the shape (especially near the corners) while it continues to cool for the next 2 or 3 minutes.

There's 2 things I see immediately that I don't like.
1. I don't like the distance between the spine of the sheath and the tip of the knife. This is one of the things that can difficult when molding a folded sheath on a blade with a lot of drop in the point.
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2. As expected (the reason I rarely use any resin, c-tek, kirinite, etc..type products anymore) the heat and pressure from molding the sheath transferred the pattern from inside of the kydex into the surface of the resin in the handle. I'm going to have to touch up the sanding and re-polish the handle when I'm finished here :( .
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This was a good thing to have happen in a demonstration IMO. Now I can show you that you can re-do if you don't like your results. :)
Back in the oven...
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As it re-heats it will come back to it's original flat shape. Then you can just try again :rolleyes: :) .
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I like this better.. :D
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Now it's time to lay out the shape. I pencil it in so I have a guide to follow for cutting and grinding.
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The top eyelet under the plunge line is key to the function of the sheath. The location of this eyelet will have a big affect on the retention. Too close to the knife and it will be tight no matter what you do, and too far from the knife and the kydex will flex too easily and never hold securely.
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Once you've set the top eyelet position, you can measure the others from there for specific spacing or just add them anywhere if you want. In this case I am setting them with 1" spacing to accommodate a Spyderco G-Clip.
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The size #8-8 eyelets I am using require a 1/4" hole. This size works well with .080" Kydex.
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This reminds me..you might need some help figuring out what size eyelets you want. I prefer to use .080" kydex so my eyelets are typically #8-8 but you might want to use different thicknesses or different hole size so here's a little reference for figuring out which size to use..

#6-6 = 3/16" hole for .060" kydex
#6-9 = 3/16" hole for .080" and .093" kydex
#6-12 = 3/16" hole for .125" kydex
#8-6 = 1/4" hole for .060" kydex
#8-8 = 1/4" hole for .080" kydex
#8-9 = 1/4" hole for .093" kydex (these say they're good for .080" and .093" but these are a PITA if you're using .080")
#8-12 = 1/4" hole for .125" kydex

With each hole I drill, I set an eyelet in it just to ensure the kydex can't shift while I drill the next hole. This isn't really a problem with a folded sheath but it's a habit I developed because it is a problem with 2 piece sheaths if you're not doing something about it.
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Now that the holes are set I'm going to get the shape close to the finished shape. First I'll cut it out, then I'll grind it. I use a band saw for cutting and a belt grinder for grinding. But, Kydex is very soft and you can use a lot of tools for this. You can cut if out with a number of different power and non-power saws. You can grind it with files and rasps, oscillating sanding wheels, spindle sanders in a drill press, sandpaper wrapped around a pipe, whatever ya' got. ;)
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After grinding the edges need to be cleaned up. I use a razor blade and trim all of the excess.
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Then I'll clean it up further with some 320 grit sandpaper followed by some 1000 grit.
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At this point I look for the areas that are binding too much and mark where I want to trim to the final dimensions.
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On a folded sheath I do as much trimming and shaping as I can (hopefully all of it) before setting the eyelets because I like to be able to pry it open a little a wash it out. Otherwise it's just more difficult to get all of the little bits of Kydex dust out.
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Setting the eyelets -
You can get a basic eyelet setting set and put it in your drill press. There are other, better presses and eyelet setters but this will work just fine for very few $$. These are available through knife making supply companies on-line.
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I suggest lightly lubricating the base to make sure the brass slips easily and evenly as it stretches. By "lightly lubricated" this is what I mean.. 1 drop of lube..
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^This is also what I would suggest for lubricating a folding knife pivot.

Make sure the top and bottom are aligned.
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Hold your sheath up against the top piece and use the press to lower it straight down over the base.
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When you make contact with the base give it a quick, firm jolt to flare it. If you go slow you will be more likely to get an uneven bend/flare.
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After you flare all of them, flip your base over to the flat side and press all of them firmly again.
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Backside-
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Front-
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Now, I need to address a mistake I made...
:mad: :o :rolleyes: Oops! I "trimmed" too much! By trying to take the "thumb" ramp a little further forward I went too far and exposed the thumb ramp on the knife. Now I won't be able to push this part of the sheath to help the knife out.
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Frankly, it's just as well.. ;) ...I wasn't loving this color or this shape anyway. I think I'll go with the blue instead :D .

Just imagine all the same steps..but in blue :D ;) .
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When I considered eyelets I was intended to go with brass again. I usually choose to match the eyelets to the corbys in the handle. I almost never mix metal accent colors :confused: , that's just nuts :p . In this case the yellow of the brass against the blue sheath was just too "loud" for me. I don't prefer sheaths to be all that noticeable, so I went with black chrome even though it's a little out of place within the whole color theme I had going. :o
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As I mentioned earlier, the eyelets are spaced to fit a G-Clip.
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Last thing to do is clean up the handle "damage" from the heat earlier, restore the finish, and then polish the edges of the sheath.
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Kydex polishes nicely by rubbing it fast on the leg of your jeans. Instead of wearing out my pants, I just attached pieces of canvas cloth to a board and called it a "sheath polisher". Great free tool! :)
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OK..sheath is ready to go! My Mule is now ready for adventure :D .
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Hopefully this will serve as a helpful guide for anyone wanting try making their first Kydex sheath. If you're temped I would encourage you to do it! It's pretty easy and doesn't take much longer than it would take to read this post. :p

Best regards to all!

Chad Kelly
:spyder: Spyderco fan and collector since 1991. :spyder:
Father of 2, nature explorer, custom knife maker.
@ckc_knifemaker on Instagram.
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standy99
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Re: Making a Kydex Sheath (step-by-step)

#2

Post by standy99 »

Thanks Chad :spyder: :spyder:
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Re: Making a Kydex Sheath (step-by-step)

#3

Post by Bolster »

Another fantastic how-to! Chuffed to have this info--copy-saved to hard drive!

I hesitate to ask for more info, after you've given so much, but...are there any rules of thumb for placing that critical first eyelet?
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Re: Making a Kydex Sheath (step-by-step)

#4

Post by Xplorer »

standy99 wrote:
Fri May 21, 2021 1:57 pm
Thanks Chad :spyder: :spyder:
My pleasure! :)
Bolster wrote: ...are there any rules of thumb for placing that critical first eyelet?
Sort of, but it's important to consider every knife is different. Some knife/handle designs provide more area for the kydex to grip than others. Some designs require the kydex to be allowed to flex more than others. There are variables within each knife design that cause you to need to figure out the best placement for that first eyelet. You can get a feel for where you want it by just squeezing the sheath in different areas and trying to remove the knife prior to adding any eyelets. Still there's a bit of trial and error involved.
If you look at the tan sheath I made compared to the blue sheath, you'll see the first eyelet in the blue sheath is farther away from the blade and farther from the top edge of the sheath than the first eyelet in the tan sheath. This is because I thought the tan sheath was holding a little too firm. That small adjustment made the blue sheath release the knife a little easier and now it feels just right.
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Last edited by Xplorer on Sat May 22, 2021 9:49 am, edited 1 time in total.
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Re: Making a Kydex Sheath (step-by-step)

#5

Post by PeaceInOurTime »

Nice work! Those scales are really nice, too!
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Re: Making a Kydex Sheath (step-by-step)

#6

Post by AlexRus »

Awesome! :)
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Re: Making a Kydex Sheath (step-by-step)

#7

Post by Xplorer »

PeaceInOurTime wrote:
Sat May 22, 2021 4:36 am
Nice work! Those scales are really nice, too!
Thank you! :)
The scales are a little more simple than what I usually do but I wanted to keep the "how to make a handle" thread easy. While the resin is not my favorite material to work with, the mix of wood and resin sure does look pretty. :)
AlexRus wrote:Awesome! :)
Thank you! :D
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Father of 2, nature explorer, custom knife maker.
@ckc_knifemaker on Instagram.
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Re: Making a Kydex Sheath (step-by-step)

#8

Post by Bolster »

Xplorer wrote:
Fri May 21, 2021 10:49 pm
You can get a feel for where you want it by just squeezing the sheath in different areas and trying to remove the knife prior to adding any eyelets. Still there's a bit of trial and error involved.
Ah, the old pinch-with-your-fingers ploy, eh? OK, will do. Thanks much!
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Re: Making a Kydex Sheath (step-by-step)

#9

Post by AlexRus »

:D
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Re: Making a Kydex Sheath (step-by-step)

#10

Post by Xplorer »

^ This is what I hope to hear. Looking forward to seeing it! :)
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Re: Making a Kydex Sheath (step-by-step)

#11

Post by AlexRus »

Xplorer wrote:
Sun May 23, 2021 9:58 am
^ This is what I hope to hear. Looking forward to seeing it! :)
:D
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Re: Making a Kydex Sheath (step-by-step)

#12

Post by Xplorer »

Bolster wrote:
Sat May 22, 2021 11:20 pm

Ah, the old pinch-with-your-fingers ploy, eh? OK, will do. Thanks much!
Yes, the old tried and true pinch-with-your-fingers ploy ;) . Works great for sheaths, mixed results elsewhere :p .
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Re: Making a Kydex Sheath (step-by-step)

#13

Post by Artvitel »

Thank you, Chad!
Nice sheath, and very useful tutorial to create it 👍
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Re: Making a Kydex Sheath (step-by-step)

#14

Post by PineyBoy »

I love the final result.
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Re: Making a Kydex Sheath (step-by-step)

#15

Post by Michael Janich »

Outstanding tutorial!!!

Thanks, Chad!!!!

Stay safe,

Mike
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Re: Making a Kydex Sheath (step-by-step)

#16

Post by Xplorer »

Michael Janich wrote:
Wed Jun 23, 2021 7:09 am
Outstanding tutorial!!!

Thanks, Chad!!!!

Stay safe,

Mike
I'm happy to hear you found it helpful Michael! :D

Best regards,
Chad
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Re: Making a Kydex Sheath (step-by-step)

#17

Post by sal »

Hey Chad,

We really appreciate your doing this. You are a real asset to the forum.

sal
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Re: Making a Kydex Sheath (step-by-step)

#18

Post by Xplorer »

sal wrote:
Wed Jun 23, 2021 12:00 pm
Hey Chad,

We really appreciate your doing this. You are a real asset to the forum.

sal
Thank you very much Sal! :) I truly appreciate the Mule program and the fact that you've brought it back.

I'm hopeful that the tips I've offered on these threads help more people see that they too can make their own handle and sheath if they want to.

Best regards,
Chad
:spyder: Spyderco fan and collector since 1991. :spyder:
Father of 2, nature explorer, custom knife maker.
@ckc_knifemaker on Instagram.
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Re: Making a Kydex Sheath (step-by-step)

#19

Post by Bolster »

The other necessary tutorial IMO. Bumping to the top for Tom.
Steel novice who self-identifies as a steel expert. Proud M.N.O.S.D. member 0003. Spydie Steels: 4V, 15V, 20CV, AEB-L, AUS6, Cru-Wear, HAP40, K294, K390, M4, Magnacut, S110V, S30V, S35VN, S45VN, SPY27, SRS13, T15, VG10, XHP, ZWear, ZDP189
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Re: Making a Kydex Sheath (step-by-step)

#20

Post by Ramonade »

Thanks a lot @Bolster ! I made scales in the past but never Kydex sheath. Never even occured to me that I might have the necessary tools.

And an even bigger Thank you to Xplorer ! It takes time to be that explicit and visual with a tutorial.
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