Kydex Tips

H

Harley Boatman

Joined
Jun 21, 2020
Messages
98
Hey guys!

Every time I do a kydex sheath it ends up being SUPER tight once I put the rivets in. I built my press with those foam workout pads to try to save money. I'm wondering if that's what's making the sheaths so tight, like maybe the foam is too firm.

If anyone knows what I'm doing wrong or if anyone has any kydex tips in general I would love to hear
 
I doubt its the foam. I used to use the same stuff and just got the proper foam and now I get a much better and tighter fit.

More likely, the foam your using doesn't form the Kydex tight to the knife leaving a bit of gap at the edges of the bolster . handle. Then, if your rivets are too close to the knife (this area that's slightly spread apart) they pinch the kydex together making it tighter.

Are you taping the knife the before putting it in the Kydex press? Most guys use a couple layers of masking tape to give a little clearance. I use2 layers of green painters tape on each side.

If it's too tight, just take a heat gun or a torch (preferably a heat gun) and warm up the sheath in the tight location. the kydex will relax and you can form it by hand or put the knife back in it. Low on it to cool it down and it'll be good in a couple minutes. You can also toss the entire sheath back in then and repress it even after the rivets are in. I just find the heat gun faster and more localized.
 
Coupe layers of tape on the blade for a little air space.

I only run the Kydex up about an inch on the scales and if I was going to go further I would use tape to create space.

My sheaths are always tight coming out of the press then I have to end up using a little stone on dremel to create space and perfect fit.
 
I started a thread about something similar (though it was lack of “pop” into the sheath) and got some excellent advice. A picture of one of your sheathes would be super helpful.

Super important where you put those first rivets too. If they’re too far back towards the handle, your sheath will never properly wear in and loosen up.
 
Where does the Kydex get a hold of the knife? The point about the position of the first eyelet/rivet is important. You can get a feel for how the sheath will be before putting the rivets in by using small G or Kant clamp where you want the rivet to go. Other factors are whether the sheath is pancake or taco. A taco where the fold over extends up the handle will be stiffer than if you cut the fold back or have a pancake. The Kydex is like a spring board, the longer it is from its fixed support, the more easy it is to flex.

Lets say you have a single guard, and the Kydex has formed around it and met on the handle side. If you want to get the knife out, the Kydex "spring" has to flex a full half guard width to the side to let the guard past, assuming both sides can flex equally. If you cut the Kydex back, so that only a little is wrapped around the guard, then you only need to flex the spring by that small amount. Another thing, rather than cut you can locally hot mould with a heat gun and cotton gloves to make a bit of a flare to guide the knife in.

If you have a Kydex belt loop, does that touch the mouth of the sheath and put pressure on it when trying to move the knife?

Chris
 
Are you setting the rivets without the taped blade inserted?
 
Cliff Carter Knives said:
I started a thread about something similar (though it was lack of “pop” into the sheath) and got some excellent advice. A picture of one of your sheathes would be super helpful.

Super important where you put those first rivets too. If they’re too far back towards the handle, your sheath will never properly wear in and loosen up.
Click to expand...

I’d agree, the first eyelet has a huge effect on how tight the sheath is. I think of it as putting the eyelet far enough away from the lip of the sheath to allow the Kydex to flex, allowing the knife out.
If it’s too tight along on the blade, then put a layer or two of tape on the blade prior to forming.
 
scott kozub said:
I doubt its the foam. I used to use the same stuff and just got the proper foam and now I get a much better and tighter fit.

More likely, the foam your using doesn't form the Kydex tight to the knife leaving a bit of gap at the edges of the bolster . handle. Then, if your rivets are too close to the knife (this area that's slightly spread apart) they pinch the kydex together making it tighter.

Are you taping the knife the before putting it in the Kydex press? Most guys use a couple layers of masking tape to give a little clearance. I use2 layers of green painters tape on each side.

If it's too tight, just take a heat gun or a torch (preferably a heat gun) and warm up the sheath in the tight location. the kydex will relax and you can form it by hand or put the knife back in it. Low on it to cool it down and it'll be good in a couple minutes. You can also toss the entire sheath back in then and repress it even after the rivets are in. I just find the heat gun faster and more localized.
Click to expand...

Now that you say that I'm pretty sure you're exactly right. I do tape the knife, I think I only did 1 layer of tape tho. I have done that with the heat gun, but it's always a struggle back and forth between too loose and too tight
 
Seedy Lot said:
Coupe layers of tape on the blade for a little air space.

I only run the Kydex up about an inch on the scales and if I was going to go further I would use tape to create space.

My sheaths are always tight coming out of the press then I have to end up using a little stone on dremel to create space and perfect fit.
Click to expand...

Which area do you dremel out?
 
Cliff Carter Knives said:
I started a thread about something similar (though it was lack of “pop” into the sheath) and got some excellent advice. A picture of one of your sheathes would be super helpful.

Super important where you put those first rivets too. If they’re too far back towards the handle, your sheath will never properly wear in and loosen up.
Click to expand...

W3Dx0BA.jpg

HnTpAak.jpg


Here's a couple of my sheaths

I'd love to read that thread if you have a link to it
 
C_Claycomb said:
Where does the Kydex get a hold of the knife? The point about the position of the first eyelet/rivet is important. You can get a feel for how the sheath will be before putting the rivets in by using small G or Kant clamp where you want the rivet to go. Other factors are whether the sheath is pancake or taco. A taco where the fold over extends up the handle will be stiffer than if you cut the fold back or have a pancake. The Kydex is like a spring board, the longer it is from its fixed support, the more easy it is to flex.

Lets say you have a single guard, and the Kydex has formed around it and met on the handle side. If you want to get the knife out, the Kydex "spring" has to flex a full half guard width to the side to let the guard past, assuming both sides can flex equally. If you cut the Kydex back, so that only a little is wrapped around the guard, then you only need to flex the spring by that small amount. Another thing, rather than cut you can locally hot mould with a heat gun and cotton gloves to make a bit of a flare to guide the knife in.

If you have a Kydex belt loop, does that touch the mouth of the sheath and put pressure on it when trying to move the knife?

Chris
Click to expand...

The sheath in that first knife I posted was super tight all along the blade as well. I think I'm understanding what you mean about how much the sheath has to move to let the knife out. You can see I ended up trimming back a lot around the area of the finger choil which led to it grabbing on to just the sides of the scales. I see a lot of guys have the eyelets right up next to the blade with no problems (I'm assuming no problems or they wouldn't keep doing it that way)

I guess my first eyelet is too far back?
 
AVigil said:
Are you setting the rivets without the taped blade inserted?
Click to expand...

Yes, I've been setting them with the blade set to the side. Should I keep the blade in while I set them? I've just worried that then the blade would be stuck in the sheath if i did it that way
 
Harley Boatman said:
Yes, I've been setting them with the blade set to the side. Should I keep the blade in while I set them? I've just worried that then the blade would be stuck in the sheath if i did it that way
Click to expand...

You have to have the taped blade inserted in the sheath as you set the rivets or the sheath will be to tight.

What you are doing is like tying your shoe first then trying to insert your foot after and then wondering why it is so hard to put your foot in your shoe.

Looking at your pictures it is apparent you pressed the sheath when the kydex was not hot enough and you did not get a good impression.

You do not need to put a rivet so close to the end, kydex will act like a spring and keep retention , take a look at how far down I have the rivets on this sheath. This allows the kydex to flex as the blade is inserted and remove and lock into place

gL4QY5P.jpg
 
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Full agreement with AVigil. Don't need so many eyelets, not so close to the opening.

The sheath Harley shows has the taco fold unbroken right up the handle, making the sides that grip the scales stiffer. You could have reduced the stiffness by cutting lengthways into the taco fold. AVigil's sheath achieves this by being a pancake design.

Not something I am entirely happy to admit, but I have repressed sheaths after drilling and fixing together when I have found I haven't had the fit I really wanted. The main problem has been the eyelets getting extra hot and leaving rings on the press foam.

Chris
 
I found a picture of a Taco sheath I did.

This may give you an idea for your rivet placement.

SHqdZ3l.jpg
 
AVigil said:
The foam I got a decade ago from knife kits IIRC
Click to expand...
That's cool, I got some of their extreme foam (high definition) but after like 20 sheaths in the same spot it left permanent deformation of the foam which makes my new sheaths wavy if I use that spot anymore. Kinda disappointed in that
 
razor-edge-knives said:
That's cool, I got some of their extreme foam (high definition) but after like 20 sheaths in the same spot it left permanent deformation of the foam which makes my new sheaths wavy if I use that spot anymore. Kinda disappointed in that
Click to expand...
I wonder if they sent you the wrong stuff. I have the same foam from them since I started for sheaths and holsters and it’s very resilient. I do rotate it, but it’s lasted me 6 or 7 years so far.
I’m sure you do way more knives than me though.
 
Josh Rider said:
I wonder if they sent you the wrong stuff. I have the same foam from them since I started for sheaths and holsters and it’s very resilient. I do rotate it, but it’s lasted me 6 or 7 years so far.
I’m sure you do way more knives than me though.
Click to expand...
It is their best foam... Maybe I clamped too tight, who knows lol
 
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