First attempt at designing a Manix/Ritter slipjoint

[earthman]

Hi everyone I've finally taken the first steps into making my ideal folder that I can legally carry 24/7, here in the UK that means non locking knives with blades no longer than 3".

I've had this idea of trying to mate these two well loved/iconic knives together, I started off with a paper template, as you can see things didn't exactly work out to plan when I tried a 'working' design in plastic.

Due to not wanting a tip to handle measurement of more than 3" and incorporating a finger choil plus trying to juggle with the pivot point, overall looks in the closed position, it took on a different shape. I'm not really happy with the exact shape of the choil, I could shape the handle part a bit more but then the blade would show when in the closed position.

It's a very rough prototype indeed, not showing any details, imagine there's jimping on the handle and on the thumb ramp, that's what I love about these two knives. At this stage I have no idea how I'm going to work out the backspring/a non locking method for this knife, this is my first attempt at designing a folder so any ideas/tips would be welcome.

[earthman]

Had another go today at making another example, not really happy with the first prototype, trying to get the overall shape of the handle more rounded in the crucial spots. Still working on ideas for a backspring.

[earthman]

Today I've been working on a backspring idea, it's basically a spring loaded ball bearing, I run out of time to put another two notches in the rear of the blade, one at the fully open position and one at the half stop but you can all get the idea. Realistically I don't think the half stop is needed due to the the finger choil's, handle shape/grip.

Will this design of backspring actually work well? What do you guys think?

[Don Robinson]

That's a neat idea. How well it works depends on the leverage and a close fit of the notch to the ball.

[earthman]

Thanks for your reply, I'll pay close attention to those points when I get around to making a complete version from metal.

[RRobaldo]

Love the concept!

I like slip joint pocket knives that snap shut when they are around 30 degree's from being shut. Somewhere around that point they should start to shut on their own.

Not sure at all how yours would accomplish that, It seems to me that this work more like the detent in a liner/frame lock knife.

Still it seems like a really cool idea even if it doesn't work like a slip joint.

You could also make it work like a traditional liner/frame lock, but don't design it to actually lock. Use the "traditional" lock to hold the detent ball, but don't cut the tang in a manner that actually locks.

Have a hole in the tang for the detent ball in both the open and closed position, but leave the tang "round" instead of having a flat side for the liner to lock into.

Lance.

[earthman]

Until I make one in metal I don't know for sure if it will want to snap shut by itself, some how I doubt it, not such a big problem to me, even less likely to cut myself.

I do prefer frame lockers over spring backed back lockers for that reason.

[earthman]

Well I've made another prototype entirely from metal, just to see how/if it could actually work. I'm pleased with the results so far, the blade can be flicked open with some firm wrist flicking and it does stay in the fully open position too.

I don't suppose anyone has a spare Manix spring I could have? So far I've really only been working with what's available in my shed, I only had one spring that's kind of that size,....would love to try a stronger spring to gauge the results I have so far.

[earthman]

Well I now have an original Spyderco spring and ball bearing, I'll need to remake & resize the 'holder' for these items, the ball is 4.72 in diameter so the liners will have to be slightly milled out to allow free movement. The spring sure is stronger than the one I originally used, like on the locking version I can't flick the blade open.

I'm slowly making some progress on this project.

Here's a couple of clear pictures of how the spring/ball sit.

[earthman]

Here's a couple of pictures of my project in an almost completed package, still have a fair bit of grinding to do on the blade etc.

[metal99]

That is pretty cool man, the world of folders scares me a little lol.

[earthman]

Well I finally put a grind on the blade, this is about has far as I can take it now.