'yo-yo' Aka 'baby-bird' Folding Knife Pendant (UPDATED)




About: I made a beer mug with only a knife & a hatchet. I think that says a lot about me.

I've always wanted to design a useful pendant.

Not just a pendant.

And not just a tool.

But a tool, with such good looks that it has nothing tool-ish.

Okay, I made a DARC and I'm the proud author of The Wasp. They àre quite good looking, thank you, but calling these mindsick designs 'pendant-able' would be like pushing grandma in the nettles - Flemish expression, which means what it means.

Like a lot of people, for some reason I love knives. And so I decided that the tool a knife it would be.

Once I had a lot of fun while building the Crazy Carver, and I wanted to surf on that experience by building a simple, stylish ànd ubersexy tiny folding knife.

Why? Because I don't have my 800 years old red cedar yet to dig out a decent canoe.

And because I never made a folding knife, in fact.

And because I wanted to give my wife a gift to remember Valentines Day.

That was one month ago?!


Step 1: Prototyping

If you'll ever design a folding knife, this step is the one not to skip.

Making a prototype in light materials like cardboard, plastic or aluminium will give you a nice idea about the pros en contras of your design, wether it's too big or too small, too unpractical or just not etc.

Unless you're designing it with nice 3D software, of course, but even then you just don't have any idea if it fits nicely in your hand or not.

Make it, that prototype.

I made one in alubond - a lightweight pvc-aluminium composite that's easily drillable, carvable & grindable.

Like you've already seen, there is no such thing as a locking mechanism.

In fact, the necklace ITSELF is the locking mechanism.

When closed, the rope prevents the blade to get out of its coffin.

To open it, you need to remove the rope, open the blade with your finger nail and pass the rope through the second hole in the blade. It's not that kind of knife where you'll put a hughe amount of power on, so 'just' the rope as a kind of 'safety pin' is far safe enough.

Kind of emergency skinner, you know.

Too unpractical in case of a cobra attack - however, fear can do strange things with humans' reflexes...

Step 2: Building Supplies

The supplies for this project are quite elegant, in fact, you just need 3 washers - two washers made of solid wood and one made of carbon steel.

I made the wooden discs out of a cheap cutting board. Most of the time those boards are made of quite okay beech and they have a quite okay (10mm) thickness. Great stuff for small projects.

The carbon steel washer is another story. In my Crazy Carver project I had been able to drill a nice hole in an old machete with a clock drill - easy - and I decided to do this simply over again.

Sacrificing one of my earlier knife designs sounded like a great idea, since it was made of an old high-quality butchers axe.

In fact, it wasn't a good idea at all. Even a heavy duty clock drill (worth $55) made only a few scratches on the blade (!).

Axe 1 - bart 0.

Instead of grinding it brutally and irresponsibly down, I sacrificed another setup.

Lower quality steel 0 - bart 1.

Note the 12mm hole in the middle of the 3 washers. Even with so called 'lower quality steel' it's still everything but a joke to make it. Start with a 5mm drill. Then 6, 7, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5 and then, finally, the 12. Lubrify as much as you can, you'll need it.

Step 3: Drill It Once, Drill It Right

After the big 12mm hole, smaller ones will follow: one of the axis (3mm), two for the safety pin aka rope (5mm).

Look at the position of the holes, that's where that prototype was made for.

First things first. The first axis hole in the blade will lead the way to drill the axis holes in the woodies.

Once the axis is temporarily installed you can drill the smaller holes all the way through the three layers.

Note: only the blade has 3 holes.

Note bis: I'll post some plans to make it all a lot easier to reproduce. Just for you guys.

Step 4: Shaping Calimero

When the painful drilling is finally behind, it's time to do the shaping of the blade. Read: removing the concave and the convex side to get a 'beak-shaped' design - more like a chick-head, in fact.

I used a grinder, and since I didn't want to lose the temper of the blade a lot of water was used to cool it while I shaped it. Melting water, from our backyard glacier.

Round the edges of the drilled holes, do some sanding, sharp the cutting edge and your blade is ready to rock.

Step 5: Assembling

Once the blade's done, all you need to do is glueing a spacer between the two former cutting board pieces - on the cutting edge side of the blade, of course, and adding two rivets all the way through.

Alubond as spacer is great. If you really feel good, you can use a piece of the same steel as the blade.

As you see, I felt bad.

Drill tiny holes first all the way through, put some glue on the rivets aka nails and smash them with love and precision through the whole. Be careful, beech splits EXTREMELY easily. This isn't the step where you want to ruin your project.

Some sanding, some sanding and some sanding later, you're done.

Finish with walnut oil. No stickyness, great shine.

The result is what you call 'a small knife'. Compact, quite good looking (my opinion), razorsharp and extremely well fitting in someones hand. A bit too big for a womens hand, maybe - and also a bit too heavy to wear around a fragile girls neck - but as a second prototype it was definitely worth the few hours in the workshop.

Step 6: Wear It With Pride

And use it wisely.

'Thank you so much, but why I'm getting a YO-YO?!' my wife said.

It took me only ten minutes to show her the secret of the gift...

Happy Valentines Day, btw.


Maybe I should make it elliptic...

Step 7: Perspectives... Aka the Birth of Baby Bird

Beech is okay, but not more than that. To get a decent strength you need a quite thick piece - use a disc of 5mm and it will break when you just turn the music too loud - and since I really wanted to reduce the 'yo-yo-factor' of the design I decided to scale down the thickness.

Beech is out, olive is in.

Same concept, different design.

Less Yo-Yo, more Baby-Bird...

Check out the story behind the scene...

Step 8: Useful Numbers

Blade 2.0 - more steel on the cutting edge side, two curves on the opposite side.

This version's gonna be awesome.

Necklace Challenge

Runner Up in the
Necklace Challenge



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39 Discussions

Slime Eel

3 years ago on Introduction

This looks awesome! I'll try to make one but since I don't have a clock drill I'm going to try to forge a leaf spring into the blade.


4 years ago on Introduction

and congratulations to you for making it to the final round. May the best 'ible win. Haha, where can I get a clock drill?

And I love the olive

2 replies

Reply 4 years ago on Introduction

Honestly, your design standed out! I'm not going to say that the best design won this time. The best design was that with the turquoise, point. Next time better my friend!


Reply 4 years ago on Introduction

I second that! I'm sorry to see you didn't pull off the win; I really thought you had it.


4 years ago on Introduction

Really interesting design, I could see it being very comfortable to use. I have to say though, and I would hope some one would tell me this about one of my own, there are several details swiftly skipped over without proper explanation. I do however like all of your links. :)

3 replies

Reply 4 years ago on Introduction

Thanx Attmos! Don't worry about those details, I planned to post a few plans to make it a lot easier to reproduce...


4 years ago on Introduction

Kinda creepy looking,which is always good.I like it.


Reply 4 years ago on Introduction

There's a tiny boundary between pendants and omas. Sometimes the oma IS the pendant, also. Haha.

Am I the only one that finds this a little bit disturbingly weapon like? Why is the knifey thing a yo-yo? Why isn't it just a yo, so that it doesn't yo the other way and cut your fingers or some poor sod's face or something? Don't really get the grandma humour (?) either. Help I'm lost here!

Tecwyn Twmffat

4 years ago

Excellent as always, you have my votes . Is grandma still stuck in the nettles, I am worried about her?

6 replies

The moment I threw her, I forgot that the nettle season hasn't started yet.

Concrete hurts more than nettles, in fact...

She's still using a German helmet as a bread baking pan. 'German bread' means something very particular at her house...

I'll send you over a bottle of my special sugar free sloe gin, which apart from curing all known physical ailments, will cause uncommunicative grandmothers to reveal their darkest secrets and protect them from being pushed into patches of nettles.