Kydex Shealths - "Snapping" In and Out

[RebelYell]

Some sheaths I notice have the blade "snap" in and out allowing it to be essentially tossed around (if it needed to be) and the knife would not come out but at the same time not scratching the blade or breaking the sheath etc.

How is this done? I imagine you can make a small notch or hump at some point on the handle or blade to do this but I just dont know. Could someone enlighten me? Im going to make my first kydex sheath in the next week or so and would love to have this so I could carry it horizontally on my belt.

 

[NoahL]

Some sheaths I notice have the blade "snap" in and out allowing it to be essentially tossed around (if it needed to be) and the knife would not come out but at the same time not scratching the blade or breaking the sheath etc.

How is this done? I imagine you can make a small notch or hump at some point on the handle or blade to do this but I just dont know. Could someone enlighten me? Im going to make my first kydex sheath in the next week or so and would love to have this so I could carry it horizontally on my belt.

If your knife has a finger guard or choil of some kind then this can be done. The kydex just gets pressed around it and you have to loosen it up a bit so you can get the knife in and out, but it still snaps. The kydex melters in the forum will have more detailed instructions, I imagine

 

[EdCaffreyMS]

What I have learned about kydex, and making it "snap": The knife itself must be designed with the use of kydex in mind. Noah nailed it.

I have had a number of folks who have asked me to build kydex sheaths for their knives....and I always have to tell them that they will have to send me the knife, and then we'd see. In reality you can make a kydex sheath for just about any knife....but unless the knife is designed with kydex in mind, it's never going to work well.

For a long time I just flat refused to work with kydex, but had so many folks requesting it for my EBKs that I finally gave in. I actually had to slightly redesign the knife pattern to make it work well with kydex, but kydex has now become the standard sheath material for my EBK line of knives. In fact since the redesign for kydex, I don't think the knives work well with leather sheaths.

 

[RebelYell]

Hypothetical here but say I made a small hump on the handle or something and pressed the kydex around it. Possible? It would keep the pressure off the blade and allow for the snap no?

Also, the other thing is the way like say the Izula does it.

Seems like they compress it somewhat around the back of the blade allowing it to click in.

 

[RebelYell]

Also, something I dont really understand is how you can have a curved handle etc as seen here and still be able to pull out the knife from something that was compressed. Something like this.

It seems extremely difficult.

 

[EdCaffreyMS]

I download, and doctored your pics to try help explain a couple of things...

The first thing with kydex is to put a layer or two of masking/painter's tape over the portion of the knife that will be inside the kydex when your molding it. Kydex shrinks slightly as it cools, and that extra couple of thousandths of room that the taping provides is often times the difference between success a failure.

I placed an arrow on this photo to indicate what portion of the kydex "grips" the knife. In this case, I don't think that sheath is kydex...more likely it's injection molded plastic, which is a different animal. However, if you notice the overall shape of the blade/knife, it tapers (top and bottom) towards the tip...which is an advantage when using kydex for a sheath.

In order to make kydex work for this type of blade/knife, the top is going to have to be trimmed basically as I have indicated with the inside curve of the arc. The arrow indicates where the kydex "grips"/snaps with this type of knife. Your thickest area is of course the handle, and that finger groove is where the kydex must "snap" over the knife. I can't be sure, but the handle appears to be wood? If so, that's a poor choice because the kydex will eventually start scarring up/abrading a wood handle. If I produce a knife of this type, and the customer indicates they want kydex, I will only handle the knife with something tougher than the kydex...such as Micarta or G10. Otherwise I know the knife is going to come back to me sometime in the future for new handles.
The other thing that doesn't make this knife a good candidate in my opinion is the way the spine of the knife curves up in the middle...in some cases it's going to interfere with inserting/withdrawing the knife, and in the worst case the knife simply will not come out once the kydex is molded. That's a prime example of what I was saying previously about the knife needing to be designed with the use of kydex in mind.

Hope that information is helpful!

 

[RebelYell]

Well I realized the sheath wasnt kydex but hypothetically, could I use a similar design? Maybe tape up the blade except for that area around the rear? Here is a pic of my first (unremarkable) blade from my HF 1x30 grinder and no real knowledge of what I was doing. Likewise, the kydex sheath for it will be about on par but its all about learning right?

Now forgive the crude edit, I did it on photonbucket but I tried to show where I would tape and then leave it off maybe creating a tighter fit on the rear and keeping in the blade but not too tightly as to screw up the blade.

 

[EdCaffreyMS]

I've tried the selective taping in the past, and never had good success with it. In most cases the kydex molded too tightly in the non-taped area(s) (specifically like you indicated) and I had to wind up cutting the kydex off the knife. I not only tape the blade, but also that portion of the handle that is covered in kydex when the knife is inside the sheath. Don't get too worried about making the tape lie flat in the area where the front of the handle material is...when you press the kydex, the tape will lay flat...and in most cases your biggest challenge is getting the tape off afterward!

Chances are that it's going to take some experimenting to figure out what works best for you, but just try to think about those parts of the knife that will interfere when inserting/withdrawing the knife, and what areas of the kydex is "holding" the knife in place...then work from there.

 

[RebelYell]

Well damn. Sounds like its pretty much a lost cause then. Noah's post mentioned fitting it and then loosening it up around the "choil/finger guard". Maybe something with a heat gun? IDK anymore. I think now I get what your saying about it tapering towards the blade..damn. Sounds like Ill just have to do this in the future...bummer. I really liked the way people were talking about horizontally carrying it on your belt loop since I cut a whole lot of boxes at my job and it would still be relatively concealed then but I just do not want something that would potentially slide out at any given time.

Hypothetical - Take a drill bit and drill a small hole, maybe around a 1/16 deep at most and put it in the blade. Mold the kydex around the knife itself and then when you press it, it will be slightly indented. It will hold it without being too abrasive and can pop in and out? Eh?

 

[Frstr8]

RebelYell


Here are a couple of observations from a user standpoint. First, you mentioned in your original post the possibility of kydex and not scratching the blade. This is almost impossible in my experience. you can line the kydex and it helps. Even with lining all it would take is for one little piece of sand to get into the sheath and it will scratch the blade. I have several knives with kydex sheaths and they ALL mark the blade. I live in the desert and use my knives. They can and DO get sand in them and scratch the blade.

Second, there are many ways to make kydex hold well. Drilling a hole in the knife works, but it has to be fairly large. You can also use a screw with a rubber o ring between the 2 pices of kydex to make the fit adjustable.

The best way to get the snap you want is for the handle to snap into the sheath.

I am not a maker of knives or kydex sheaths. These are just my observations from using many different kydex rigs from different makers / companies. If you would like me to post pictures of several different variations I can and will do that when I get home from work tonight.

Hope this helps.

 

[RebelYell]

Absolutely. Whatever you have to offer me will help.

Also, you say the hole needs to be large? General size? I imagined like 3/16ish wide, with it drilled maybe 1/8th plus maybe a few mm down.
If I found a place to parkerize the blade, I imagine the kydex wouldnt really scratch it at all yeah?

Lastly, you mentioned the handle. do you mean some kind of "notch" or some similar feature that way the blade itself wont have friction on it but it will still "catch" and lock into something? IE, a small hump on the handle or something similar.

 

[Frstr8]

The size of hole would have to be proportionate to the size of the knife. The bigger and heavier the knife the bigger the hole. I will try to get some pictures up soon.

There is a great tutorial on kydex sheaths somewhere. Can't remember who did it though? Maybe MO.

 

[Justin King]

If you notice on most kydex sheaths the eyelets that are used to rivet it together usually stop an inch or so from the point where guard or the end of the grip "snaps" into place. This is deliberate and allows the kydex to flex and for the two halves to seperate at the top which allows the fat part of the grip to be withdrawn and inserted.
A parkerized blade will still get worn and scratched if the inside of the sheath gets contaminated with enough grit. If you do like Ed said and use tape to mold the sheath a little loose, this will be minimized but I doubt if it can be completely eliminated. This is fine for user knives because they get scratched from use anyway. The rub marks from the kydex just blend in eventually.
If you want your knife to stay pretty make a wooden box for it and leave it in the house, I say. If it is a user I recommend taking it out as soon as you are through gazing at it with moist eyes, and putting a nice first scratch on it. That way you can go ahead and get over it and start putting the knife to use

 

[RebelYell]

Yeah Im not terribly worried with cosmetics, just trying to understand all paths. Is it common/possible to thinly line the inside of a kydex sheath with say cloth or...I dont know. Im sure this has been thought of before.

 

[Frstr8]

With the help of my little blue buddy I will show you a couple of the sheaths I was referring to.

First we will look at the Benchmade 210 sheath. It has a screw and O' ring set up that allows it to be adjustable.

This next picture shows where the knife's friction point is.

Next we will look at the Martin Olexey FOS. This knife's friction point is on the blade.

This FOS snaps in and out of the sheath with authority!

If you have any more questions or need more pictures or what-not just let me know.

 

[RebelYell]

Sir, could I see the knives themselves out of the sheath? Also, on the oring bit, does it adjust...well, rephrase, does it push things apart or pull them together. Im making sure I fully understand. Also, it just seems like the blade would slice that oring but I have no idea. Does it snap in or just make it hard to pull out? Also, how did you form that bulge on the bottom? How did you measure the proper thickness of what I imagine you shoved in there.

Now, on the second one, it seems like its slightly wrapped around the thing I imagine to be a finger guard but wont scratch the blade and is still wide enough to pull out. Did you ever find one of the hole in the blade? No biggie, I just remember you saying the size of the hole should be relative to the blade so itd be nice to be see. To be honest, that seems like the option I like the most.

By the way, blue man is legit.

 

[Frstr8]

Sir, could I see the knives themselves out of the sheath? Also, on the oring bit, does it adjust...well, rephrase, does it push things apart or pull them together. Im making sure I fully understand. Also, it just seems like the blade would slice that oring but I have no idea. Does it snap in or just make it hard to pull out? Also, how did you form that bulge on the bottom? How did you measure the proper thickness of what I imagine you shoved in there.

Now, on the second one, it seems like its slightly wrapped around the thing I imagine to be a finger guard but wont scratch the blade and is still wide enough to pull out. Did you ever find one of the hole in the blade? No biggie, I just remember you saying the size of the hole should be relative to the blade so itd be nice to be see. To be honest, that seems like the option I like the most.

By the way, blue man is legit.

Okay Here are a some shots out of the sheaths.

As for the o' ring it pushes the kydex apart, but the screw that goes through it can be tightened to bring it closer together. It just smashes the o' ring a bit. The blade does not touch the o' ring, although I suppose it could if you were very careless and wild removing it from the sheath.

You asked how I formed the "bulge" or separation on the bottom. Simple answer, I didn't. As I stated before I am not a maker of knives or sheaths. I am a no talent shlub who attempts to collect knives 2thumbs

The sheath came with the knife from Benchmade and I would assume they have some sort of jig that they form the sheaths around.

I no longer have the knife with the hole in the handle that the kydex popped into. I gave it away a while back. The hole was about a 1" hole if I remember right.
Also, as I said before there are some great tutorials for kydex out there. I suggest you start by finding them.

Hope this helps.

 

[RebelYell]

So it seems on this one

the kydex "closes" around the back end of the blade on the rear curve I guess and they probably took a heat gun or something and then somewhat pulled apart the kydex but not enough to compromise the mold on that part of the blade...seem about right to you? I ask because if you look at the picture of my first one, this seems like a doable thing for me.

And yeah, I have been reading tutorial after tutorial but this subject doesnt come up much.

 

[Frstr8]

So it seems on this one

the kydex "closes" around the back end of the blade on the rear curve I guess and they probably took a heat gun or something and then somewhat pulled apart the kydex but not enough to compromise the mold on that part of the blade...seem about right to you? I ask because if you look at the picture of my first one, this seems like a doable thing for me.

And yeah, I have been reading tutorial after tutorial but this subject doesnt come up much.

It doesn't come up much. But I know there is some good kydex sheath tutorials out there.

 

[M.Olexey]

I love a pic of a well used F.O.S. 2thumbs

I outline my sheath making process in detail in this thread....


http://www.knifedogs.com/showthread.php?t=2303

(Page 4)


A lot of high points have been pointed out here already. Design the knife with kydex sheathing in mind, tape the blade etc.....


I think the pics show the process pretty well.




MO