Flipper Friday (Making A Flipper Knife From Scratch)

[Magnus Knives]

This thread is where I'll be showing the designing, prototyping, testing, tweaking and (hopefully, at least) the producing of my first flipper knife.

Firstly, I have to get something off my chest...

I like framelock knives ...but I don't LOVE framelock knives.

Don't get me wrong. All my knives are titanium-scaled framelocks.

But it bothers me that I have to put my thumb across where the blade comes down -- together with having to change my hand position -- just to close the knife.

So here's my thinking...

If I'm going to make a flipper knife from scratch, then why not go to the very beginning and see if we can come up with a different locking (and therefor closing) mechanism.

I'm not going into this all starry-eyed and totally clueless (only a little starry-eyed ...and somewhat clueless ).

I've made a few flipper knife prototypes in the past. They got to the 95% finished stage and just needed some tweaks. All were framelocks.

Oh, and one more thing...

I'm a CNC guy. While I can only look on in awe at knifemakers who grind bevels on a knife grinder ...it's just not my style.

One of the hardest parts of the prototype knives I CNC-machined was getting the surface finish on the main bevels dialed-in. But, having spent a few hundred hours on it, I was starting to get somewhere when I put them on hold few years ago.

In terms of the locking mechanism...

I've spent a lot (a LOT!) of time over the last couple of months designing various mechanisms. Most of the initial design concepts I do in my head ...and, if they show promise, I then go to CAD to flesh them out a little more and try and discover the various flaws (of which there is always at least one or two issues and is why, currently, I'm still at the R&D stage ).

What I'll do is post where I currently am with the mechanism (various CAD screenshots).

One last thing...

Initially, I think this thread will likely have a bit of a slow-burn in terms of progress while we come up with locking mechanism.

But, once that's sorted, we should start to make decent progress with the knife overall.

 

[Magnus Knives]

Before I post some screenshots of where I'm at with the locking mechanism design...

I reckon it's important for me to cover the specific criteria for this new locking mechanism.

The reason for this is because some things in the design may not make sense unless you know specifically what I'm aiming for.

Without getting too geeky on you, here's where I'm at:

#1 -- Locking mechanism must be rock-solid and be impossible (or close to impossible) to fail. This is a MUST HAVE.

#2 -- User must be able to open and close the knife without having to change hand position (this is also a MUST HAVE and absolutely non-negotiable)

#3 -- The mechanism must be simple and consist of two or three parts at most. This, again, is also a MUST HAVE.

#4 -- The knife (and therefor mechanism) must be able to be easily disassembled and assembled by the user. MUST HAVE.

#5 -- The mechanism should be contained as close as possible to the pivot area of the blade. This is a NICE TO HAVE.

This last one is from my perspective as a maker...

#6 -- The mechanism must be CNC machinable and (ideally) not require constant tweaking and adjusting during production. This is not a deal-breaker on my side ...just a NICE TO HAVE.


I think that's it. Some screenshots to follow.

 

[Magnus Knives]

The blade and scales are just a crude placeholder while the lock gets developed.

The blade has a typical crescent shape ...but the small grey circle is a push-button (not a stop-pin).

There is a small spring inside the push-button. The spring would be Titanium (we have made these before for pens ...just not quite this small).

 

[Magnus Knives]

In the above images it's hard to tell ...but the pin has a taper to it. And, similarly, the blade as the equivalent taper to accept the tapered pin.

 

[Magnus Knives]

Here's the knife from the left side (where the push-button would be to release the lock of the knife and allow the blade to shut).

 

[Magnus Knives]

In this next image you can see I've added another cylinder and spring. This is for a detent ball to keep the knife closed and allow it to load-up and flick open (just like a regular framelock).

 

[Magnus Knives]

...and this is where I suddenly don't like where the mechanism is right now.

To me it's starting to get a little messy. Too many parts.

There is also a problem here that there will likely be some "play" in the pin. Although the pin taper will fit snug into the blade taper, there will likely be some back-and-forth play. The reason for this is because the pin must be able to slide left to right. So while it may be loose enough to move ...this looks like it will in turn be loose enough to have a bit of play.

Now, yes, I could add a stop-pin to hold the blade from opening fully ...but I am really trying to avoid that. Although the obvious place is to put the on the top rear of the blade - I'd be more inclined to try and get it closer to the pivot area.

I'm going to shelf this concept for the time being (not forever as I think there is still something there) as I have something similar brewing - but hits the criteria better.

 

[fishface5]

Hmm I think 2 buttons puts it at a considerable disadvantage compared to a regular button lock . . . Oh we posted at the same time!

 

[Magnus Knives]

Hmm I think 2 buttons puts it at a considerable disadvantage compared to a regular button lock . . . Oh we posted at the same time!

Oh, sorry. My poor explanation there. The second one is fully internal and not a button as such.

 

[Green•Dragon]

This thread is where I'll be showing the designing, prototyping, testing, tweaking and (hopefully, at least) the producing of my first flipper knife.

Firstly, I have to get something off my chest...

I like framelock knives ...but I don't LOVE framelock knives.

Don't get me wrong. All my knives are titanium-scaled framelocks.

But it bothers me that I have to put my thumb across where the blade comes down -- together with having to change my hand position -- just to close the knife.

So here's my thinking...

If I'm going to make a flipper knife from scratch, then why not go to the very beginning and see if we can come up with a different locking (and therefor closing) mechanism.

I'm not going into this all starry-eyed and totally clueless (only a little starry-eyed ...and somewhat clueless ).

I've made a few flipper knife prototypes in the past. They got to the 95% finished stage and just needed some tweaks. All were framelocks.

Oh, and one more thing...

I'm a CNC guy. While I can only look on in awe at knifemakers who grind bevels on a knife grinder ...it's just not my style.

One of the hardest parts of the prototype knives I CNC-machined was getting the surface finish on the main bevels dialed-in. But, having spent a few hundred hours on it, I was starting to get somewhere when I put them on hold few years ago.

In terms of the locking mechanism...

I've spent a lot (a LOT!) of time over the last couple of months designing various mechanisms. Most of the initial design concepts I do in my head ...and, if they show promise, I then go to CAD to flesh them out a little more and try and discover the various flaws (of which there is always at least one or two issues and is why, currently, I'm still at the R&D stage ).

What I'll do is post where I currently am with the mechanism (various CAD screenshots).

One last thing...

Initially, I think this thread will likely have a bit of a slow-burn in terms of progress while we come up with locking mechanism.

But, once that's sorted, we should start to make decent progress with the knife overall.

I’m a CNC guys also- prototype machinist. I came hand bevel a knife to save my life either !
I’m gonna keep up with this thread it’s right up my alley !

 

[Magnus Knives]

I’m a CNC guys also- prototype machinist. I came hand bevel a knife to save my life either !
I’m gonna keep up with this thread it’s right up my alley !

I think the main thing about grinding a knife is that it's not scalable - that's probably the thing that puts me off the most.

Also, I will admit now... I'm not a machinist. I reluctantly learned it over the last few years (because I totally screwed-up my business and couldn't afford to pay the machinist I was working with and so had to start doing it myself).

In saying that... I really do enjoy it.

Here's a couple of photos (just to try and keep things interesting in this R&D stage) of some previous prototyping I did ...that never really went anywhere.

(NOTE: I'd never try and machining it like this again )

 

[Magnus Knives]

I knew it was going to be hard coming up with a new locking mechanism. But I didn't realise it was going to quite as hard as it's turning out to be.

I disregarded dozens and dozens of possible concepts before going to CAD. But now, even at the CAD stage, I'm still going through design after design. Nothing is really working out (and by this I mean meeting the criteria fully).

Here's some of the failures so far:

As you can see...

These are all based along the idea of fitting the mechanism inside the blade.

Maybe I'm not going to be able to do it and I'll have to use external stop-pins, etc.

 

[Planterz]

You should use Crucible Magnacut steel for the blade, for obvious reasons.