My Mechanical Bone-Themed Crossbow.

So I want to build a really cool looking crossbow, but without using a tradition "bow". I want it to be powered by springs and levers and pulleys.

So I've been working on designs to make it functional, but also aesthetically pleasing. I like the old Goth Horror idea of using bones to build things, so I thought I would incorporate a bone theme to it as well.

So I started with this basic design.


Then I've been designing and redesigning parts until I get the "look" I want.

Sir, I believe I'll be following this!

Like the design of it. nice work

So is it just the springs and pulleys that do the work? Are the cables and strings all rigid ie not elasticised? I'd love to make something like this but they are illegal where I live (without a licence anyway)

The string may have a little elasticity, but most of the power/force comes from the springs, through the swing arm and pulleys.

I am starting this thread a little late, as I have been working on this for about 2 weeks, but I thought I'd let my RPF friends know what I am up to,

I liked this trigger design.

(Sorry the lines are thin and the animation is hard to see.)

So I started on taking this design and adding a bit of a "skeleton clockwork" look to it.


I busted out some balsa wood to sculpt the "tickler" style trigger.

And some test pieces for the mechanism.


Rigged up a test receiver group to try out the parts to the trigger.



Then I used a local hackerspace's laser cutter to cut some plexi for a prototype.


And made some visual updates on the trigger itself.


Found I needed some reinforcement in the mid section and added a bit more to it.


So trigger is ready to mold, replicate in wax, and get cast in metal now (it's still just mostly balsa wood and paper-clay.)

Next up was getting the end piece of the bow designed, and finally I came up with this.


And then sculpted a core out of regular craft foam (one sheet of 11" x 17" red and little white for accent.)


I'm adding additional detailing and making it more anatomically correct with paper-clay.


It's slow going, it is like working with Spit-wads! But as I sculpt a little, let dry a while, sculpt a little, then dry... basically it is taking shape.

Ok, so I made several minor changes to the Receiver Group on my crossbow. Improvements on the geometry. So in the next few days I'll get another set laser cut and see if everything works perfect this time...

So I can send to the waterjet cutters!!

I did more sculpting on the jaw bone piece.

That looks cool. Foam for the core and what is it covered in?

think he said paper-clay not heard of it before so looked it up


more info here http://www.paperclay.co.uk/clay.htm

It is looking really good. I am following this with much excitement. I love the design of the bow.

Great work!

Pobbrett said:

---

think he said paper-clay not heard of it before so looked it up


more info here Paperclay Information Paper Clay Instruction Page

That's exactly what it is. It feels like sculpting with Spit-wads though!

Thanks for all the kind words of motivation, helps me keep going on such a big project.

That is some amazing mechanical design work! I love it! Very inspirational!

Ok, sorry for the wait, but I got some updates.

Updated the Bone swing arm prototype a bit more, making it fit better and look a little more steampunk.


Got my crossbow main backbone pieces back from my welder friend. They look great to me.


And here's how the swing arm will mount and pivot.


And this is what my work area looks like with 10 things going on at once!

Working on this project still.

Started a mock up on a quiver for the bolts (arrows) built out of a soda box's cardboard.


Looked a little too boxy to me, so I hit the Dollar Store and got some supplies... Grabbed 2 aluminum spray bottles, a dog hair brush, some masking tape, and a pair of chicken scissors. All on my lunch-break at work.

And after a long, NOT busy day I had this...


And after I put my crossbow bolts (arrows) in it kind of looks like this.


And yes, the crossbow bolts are hollow stainless steel CHOPSTICKS!!

Quiver update.



And here's the start of what will fill the lower opening.

really cool work you are doing on this. Subscribed!

I am REALLY digging this thread. Keep it up, sir! I can't wait until it's all done!

-Jonaas

Nobby said:

---

Excellent!
I must admit I was starting to wonder if maybe you had abandoned this one.

Looking forward to seeing the rest of the bow come together

If ADHD... so when I get to a point on a project that I need someone else help, I have to pause. Then while "waiting" I get involved on whatever other thing I'm working on... It's a constant juggle to keep all my projects active at any one time.

Plus, I can only work on stuff as I have the funds, which are extremely tight for my family these days.

Remember that metal 1/4 dome aluminum piece in the background of the above pics? It's a doorstop!
And now its a lower jaw!



Of course a lower jaw alone is...lonely, so I formed a skull face to go with it as well. It's from a vacuum-formed piece off a cool coin bank I got. Then I tucked and attached material to it to blend into the rest of the quiver.



Finally, a bit of color matching paint over the skull face. The flash makes the color a little light compared to the leather. To the eyes in regular light it looks to blend well.



So how does it look so far to you??

looking good
If I was totally anal, I'd ask if there was any way that the lower jaw could be 'squared off' a little at the bottom.

Nobby said:

---

looking good
If I was totally anal, I'd ask if there was any way that the lower jaw could be 'squared off' a little at the bottom.

Want to do a "photoshop" sketch of what you mean?