Knife lose in a kydex sheath fix?

Daniel Rohde

Daniel Rohde

Knifemaker / Craftsman / Service Provider
Joined
Jul 22, 2014
Messages
1,050
I have been having allot of trouble with my kydex sheath, the problem is when I make the sheath and get it done the knife has just a little play in it, meaning I can wobble the knife around in the sheath just

a little bit when I shake it. How can I fix it? I have tried allot of things and I'm just not satisfied with what I have been getting and making five sheaths for a knifes and still not getting it right is annoying.

I currently have been trying a oven or a electric griddle for heating the kydex with a homemade foam press and I leave it in the press for about 10mins after I get the knife/sheath in it.

Any help would be appreciated!

Daniel Rohde
 
Try taking the knife out. Use a heat gun to heat the area near where the bolster would be and flatten it down slightly with a piece of wood or metal. Then let it cool and try again. Your goal is to pinch the kydex down smaller than the knife, which you can't do while the knife is in the sheath.

Also some pictures might help me see better why it isn't locking up.
 
What kind of foam are you using in your press? What thickness kydex? Does it seem to be forming tightly? How close are your eyelets/rivets? Pics might help.

You might try a heat gun. I heat both sides, rotating every few seconds, until the kydex is very pliable, almost like wet leather, and very hot to the touch. Then I quickly stick it in my PVC foam press and crank it fairly tight.
You should be able to see a fair bit of definition (outline of the knife) in the kydex, especially thinner kydex. This should give you a fairly tight, play free sheath. Eyelet placement will then determine how tight it is, as well as any part around the opening where the kydex from each side touches itself.
 
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Yep pay special attention to the placement of the topmost eyelet too, the closer it is to the knife(and sufficiently high up), the tighter the lockup.
 
You are getting some excellent advice here!

I don't have enough kydex experience to comment, but if you need further help there's always a great group of guys in the sheaths forum with a great deal of experience. :)
 
I'll be back tomorrow with pictures and a longer answer thank you all for your help!
 
Use thick and hard foam. The press needs to apply enough pressure to form tightly to the knife. The tip about using a heat gun and "pinching" the top about 1/4" back from the opening works well. You can use the same method to close up the gap between the front and back toward the tip on a sheath that "clatters" because the blade moves back and forth too much. Properly fitted, the knife should sit pretty solidly in the sheath ...but not bind.
 
Okay guys here are some pictures:
I'm using .080" thick kydex(or close to it) it seems to be forming around the knife really well
411240799.jpg


411240802.jpg


In the press I'm using 1" thick foam from usaknifemaker and I'm using two bar clamps to tighten it down
411240801.jpg


with that picicular sheath it is hard to get to knife out it takes a pretty good pull wich is kind of annoying. I want to be able to pull the knife out well and easy and I want a tight fit up. I will try some of the suggestions.

The knife is very secure in the sheath and doesn't wiggle much but I can slightly shift it in the sheath. Also, some of the black oxide is coming off the grommets when I'm pressing them together-any idea why?(or how to fix)

Thanks for your help!

DR...
 
Are you putting your eyelets in after you press the kydex, or before? Where on the press are you placing the kydex? Closer to the front, or to the hinge side? The front, opposite the hinge will give you more pressure.
For the black wearing off, try oiling your dies before pressing them.
It also looks like you're pressing something on the underside of the ricasso/finger groove area so that it comes out of the sheath easier? This could be the cause of some of your extra play. Try using a thinner "channel", or heat up that spot slighting and pinch it together a little more. See if that helps.
 
It looks over-molded at the front choil. Some guys will use a fitted piece of wood to fill out areas like that.

There's a kydex thread that covers design issues. I'll poke around, see if I can find it.

Edit- found it.

http://www.bladeforums.com/forums/showthread.php?t=1147390

Take a look at the photos in post #2. He explains the choil spacer pretty well. The whole thread will probably be helpful.

Good luck. :)
 
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2015-05-14_08.05.42.jpg


The reason it's hard to pull out is the top arrow. If you open up the path of removal indicated by the line and lower arrow it will come out easier.


As for the slop in the sheath it looks like your clamping too close to the hinge.

2015-05-14_08.18.51.jpg
 
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@halestorm @Hale Storm

Ronnie will be able to answer this question easily. He is the only maker I trust with my knives for a reason.
 
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