Auto Deploying Kydex for Folding Knives? Tips?

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ParacordMan1220

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Feb 5, 2012
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98
So I have been wanting to attempt making a sheath that will automatically deploy a folding knife when drawn.
Here is my current attempt I have made for a Spyderco Dragonfly, but it only opens up about this much before coming out of the sheath.



A friend told me to heat up the kydex going into the sypdie hole and push it down more, making more of an indention in it. This should give it more to grab onto and delay it from popping out of the sheath before opening. Are there any other factors that could be preventing it from opening completely?




What about making an "auto-opening" sheath for an Emerson?

 
with Spydercos the best way to open it is while pulling down the knife flick your wrist downward and the force will snap it open.Same with the Emersons
The faster you draw, the better
First pic sheath looks a lot better than second...
 
Well, the way I have it set up is to be carried at 8 O'clock on my belt. In order to draw it, it would be pulled up instead of down.

And there is only one sheath :D lol. One side is green while the other is black. I believe the angle and lighting just makes it appear different. But I should reheat the top portion again to get a better contour on it. The spydie holes however are both about the same depth.
 
Cool idea , I remember seeing a video of one on the interweb a while ago .
In the first pic it looks like the blade can only rotate so far before the spine of the blade hits the sheath where the fastener is positioned .
Wouldn't it be better to raise the fastener up a bit and create a slot for the blade to continue opening further before it comes to a stop and then become the leverage point that causes the knife to release ?
I will watch with interest , because these types of sheaths interest me a lot .
Great job so far .

Ken
 
Yep make the indent deeper

From about 7 or 8 years ago when I first developed it :)

It was very tricky to get the fit just right without making it so hard that is would really have to yank your head off and too light and it would not open the knife.

IMG_4649.jpg


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IMG_4653.jpg


The one that works with the wave feature was developed by Ernie Emerson or for him, and at Blade show in 08 I asked him permission to develop it a bit further, ( it was the honorable thing to do) he said it was fine with him and he told me to go for it.
We are pretty good buddies, I like to think.

and this is what I came up with.

these work much better than the ones that work with the hole.

IMG_4642.jpg


IMG_4643.jpg


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IMG_4645.jpg
 
it can also be done without eyelets:
[video=youtube;yePA4UMRaH0]https://www.youtube.com/watch?v=yePA4UMRaH0[/video]
 
ParacordMan1220 said:
Well, the way I have it set up is to be carried at 8 O'clock on my belt. In order to draw it, it would be pulled up instead of down.
Click to expand...

i think the name is Inertia ?
the faster you draw the better your chances neck or belt carry...
 
David Brown said:
Yep make the indent deeper

From about 7 or 8 years ago when I first developed it :)

It was very tricky to get the fit just right without making it so hard that is would really have to yank your head off and too light and it would not open the knife.
Click to expand...

Thanks for the pictures! I've been looking everywhere for a close up of the indent.

So I need to make the indent deeper. Should I make the indent deeper on each side? Or will it just take some experimentation on one side at a time
 
ParacordMan1220 said:
Does anyone have an effective technique for reheating the hole indent without messing up the rest of the sheath?
Click to expand...
I haven't used this technique for this specific purpose, but it has worked for other small refittings. Use a hair dryer and make a cone of some sort to direct the heat. I used a metal funnel.
 
What ALLHSS said should work. Alternatively you can try cutting an appropriate sized hole in something that won't transfer the heat much and lay it over the spot you wanna heat up.

In any case, watch the heat build up as that kinda thing can get away from you.
 
Again, a great rendition of those original "auto opening" sheaths from the 80's! I loved those back then. :D

Rethinking and updating an original idea is a good thing. Your good in not claiming it as your own. Well done.
 
leatherman said:
Again, a great rendition of those original "auto opening" sheaths from the 80's! I loved those back then. :D

Rethinking and updating an original idea is a good thing. Your good in not claiming it as your own. Well done.
Click to expand...

It is my own idea. I've not seen any other sheath that deploys the knife a third of the way open :D;)
 
Think he was just making a joke about the partial opening.

I think this kinda sheath might be cool for a Ladybug/Manbug. Not a fan of things around my neck, but that'd be a pretty light setup.
 
Kiah said:
Think he was just making a joke about the partial opening.

I think this kinda sheath might be cool for a Ladybug/Manbug. Not a fan of things around my neck, but that'd be a pretty light setup.
Click to expand...

Yes, I didn't mean to take credit. I was referring to the kinks I still need to work out.

I actually have this set up



It sits on my left hip and keeps it out of the way.
Since it's a small knife, you don't really notice it.
 
Well, after several hours spent reheating and reforming my sheath, and making two other trial sheaths, I finally came up with a working product.



I pressed the indents down more with a small rod and used a thick piece of metal with a small hole in it to concentrate the heat. What did make it work right was something a lot more simple than I had considered: loosen up the blade pivot. Who would've guessed :D







Here is a video of the opening.

 
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A lot easier when you have a ramp or wave to work with over just a spydie hole. I made this a good while back just for grins. It deploy every time unless you hold the blade shut.



 
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