Wooden Scorpion

My goal for this project was to create a hand-held weapon that I could use to hunt small (or possibly large) game.   This is an original design I adapted from a tabletop crossbow (which I based on an ancient roman weapon) I made last Christmas as a gift for my brother.  I would say this project is intermediate level, but a determined beginner could do well also.  My wife encouraged me to document the process and share it as my first Instructable.  I have used my scorpion to target shoot, but have not yet had a chance to take it hunting.  It shoots as accurately as I could hope for in a homemade weapon, and I believe with enough power to kill small game.  I will update if/when I am able to use it for hunting. 

You will be using power and hand tools for this project, so of course proper safety precautions are a must!

Step 1 Equipment and Supplies

I had several board feet of red oak saw-mill grade lumber in my shop so I planed down a 5 ft board to 3/4" thickness and another 5 feet to 1/2" thickness.  You could use any hard or soft wood you have laying around the shop.  See Materials list below if you will be buying from a lumber yard.  Be careful with soft woods.  They may not hold up to actually firing an arrow.  The only other materials you'll need are some parachute chord (also known as 550), a small spring from any cheap pen,small finish nails and wood glue.  You could use some other nylon string but the small strands inside the 550 are very strong and worked great for me. 

Materials
1" x 8" x 6' hardwood board (this will actually only be 3/4" thick)
1" x 4" x 6' hardwood board (if you don't have the means to plane down to 1/2", DON'T buy a thinner board.  Use 1" x 4"  and adjust the tenon measurements as noted on the following step.  Your crossbow will be a bit heavier than mine.)
24 feet para-cord for springs
cheap click pen (for the spring) or make your own
finish nails
wood glue (I used Gorilla brand)

You'll also need...

Hand Tools
Square
Chisels
Ruler/ Tape measure
Clamps
Drill bits
Box Knife
Round file
Rasp
Coping Saw
Vice
Mallet
Sand paper

Power Tools
Table Saw
Scroll Saw / Jig Saw
Rotary tool/ Dremel
Drill or Drill Press
Belt or Orbital Sander

You don't need all these power tools.  They just speed up the work.

Comments

[anibioman]

im going to make this but a dumbed down version as im a beginner.

[darthbindy]

amazing! the trigger system helped me sooo much, iv been wanting to build a cross bow for ages, but all the triggers i could find where either to hard for me to build, or required tools/metals that i didnt have, thought i wont be using the bow that yours has, (im attaching an old fiberglass bow) everything else is awsome!!!!! thank you sooooooooooo much!!!!!!!!!!!!!!!!!!!!!! =)

[ducktape.mac]

that's amazing!!

unfortunately, i never have any money and i don't have the tools. what i might do though, is make it out of plastic, metal, and sweet gum saplings... thats about all that i have access to!

[the doctor who]

i built one of thes out of wood pallets

[armourkris]

Awesome. I've been wanting to make one of these ever since a built a little table top onager a couple years back. I'm glad to see other people think like me. this is deffinetly getting bumped up in my to do list.

[PotatoCoffee]

Awsome!

[lasertag1111]

I used your Instructable for the basis of this:http://www.instructables.com/files/deriv/F7H/R17Q/GTGZI7ZN/F7HR17QGTGZI7ZN.MEDIUM.jpg
I was too lazy to make the rifle-stock thing you've got going on, but it is pretty much functional and a great use of torsion. However, I don't think it could kill any animals, and I can't possibly wind it any tighter or it will break. Do decent arrows make a significant difference?

[bwells2]

Can it kill game?

[Electroinnovation]

Nicee. I made one of these once but it was around 10 feet long and I had to use steel for the arms because the 2"x2"x4' pieces I was originally using splintered!

[thelastonekills]

sweet. 5/5
sooo trying this but made out of steel and using metal springs
this is so good thnks heaps

[bowmaster]

Hunting with miniature siege weapons? Sounds like a good time.

[bombmaker2]

Do you think the size could be doubled without making the top and bottom pieces thicker? Or do you think everything should be doubled?

[skimmo]

i was thinking would you get more range if you made the distance between the frame and trigger longer, do you think the arms could stretch back more with out stressing the frame? you seem to have alot of overhang in the arrow

[omnitron]

awesome instructable! i have been wanting to build a scorpion bow for a few years but never found good instructions and the fact that this one is hand held makes it even better. the only problem im having is finding out the length of the trigger and release mechanism if you or anyone can help clear that up it would be great

[dbull]

I'm glad you are able to use my Instructable. I will take some measurements and get back to you as soon as I can.

[omnitron]

thank you

[skimmo]

this is pure epic win!

[popa27272]

i wish i had thought of tighteners like yours when i made my ballista for my physics class, i only wrapped my rope around the entire thing and twisted the arm until it was too tight to slip the peg on the outside back in. needed to use a car jack to get the clearance needed to put it back together

[dbull]

Yeah, I went through a few designs before thinking of the tighteners...I wanted to avoid the problem you had.

[brando1]

can you use bigger rope

[dbull]

are you asking about the strings for the springs or the rope that pulls the limbs back?

[curt-fullmer]

great project. Currently working on my own crossbow, i know what you mean about the red oak, pine has been breaking alot.

[dbull]

If you just want it to show off, then by all means use pine. However, pine just will not hold up to the forces exerted during firing if you actually want to shoot it. Good luck with your project!

[jlipimpski]

Pretty good instructable. Only part that was lacking were drawings (could have been cleaner) but other than that, i'm going to base one of these off your design. Thanks for sharing, i look forward to seeing more from you.

[dbull]

I also wish I could have had the drawings turn out better, hopefully I will work the bugs out of that component of the process before I do any more 'ibles. thanks

[ilpug]

this is an amazing project. although at the moment i have no free time (high school senior :/) i will definetely build one of these. love the design. excellent workmanship and simple directions. the only thing i might suggest is making the trigger mechanism out of metal. wood is slightly weak for something like that. since this is definetly a dangerous weapon, i might also suggest making a safety.
one thing i might also recomend is putting pads on the forward upright pins to reduce shock when the limbs snap forward. other things you might think of: put a forward grip so you dont have your fingers so close to the string (you can lose fingers, or at the least break them), paint it, maybe work out a sight. Don't take my criticisms the wrong way it is all purely constructive. LOVE THIS PROJECT!!!

[dbull]

Thanks for the love man, no hard feelings over the suggestions. I made this project just exactly as I wanted it to be (as much wood as possible) and it has worked great for me. Your suggestions are good ones, and would make your project unique. I recommend writing up an 'ible yourself. This took me about 10 days total, working a few hours each day after work.

[Electroinnovation]

Very cool but this is not a crossbow, it is a Roman Scorpion. A Scorpion uses rope torsion with rigid arms while a crossbow uses arms that flex when pulled back. See attached pictures. (first is a scorpion and second is a crossbow)
Nice work anyway

[skelly7447]

he said that in the title

[Electroinnovation]

Yes he changed it after I informed him.

[dbull]

I didn't originally-I added that after I verified this comment was correct. I didn't want to totally change my title and confuse people. thanks though!

[dbull]

I stand corrected, sir! I actually modeled my weapon off of pictures of ancient Roman weapons I have seen, but the books I had didn't say what they were called. Thanks for the info and the compliment.

[Electroinnovation]

And I just looked at the instructable again and you have a very cool trigger design! I build a giant version of this a few months ago (about 10 feet long) at my friends house but we never could figure out how to make a trigger...Maybe ill try to build one like this!

[dbull]

that sounds awesome. Just shoot me a message if you need any design pointers. The more I use this one, I'm sure I will come up with some tweaks to the design. I would be happy to lend a hand

[Electroinnovation]

Sounds good, thanks.

[Electroinnovation]

Okay no problem

[rimar2000]

VOTED!

[dbull]

Thanks man!

[rimar2000]

You are welcome. Today is the last votation day, I have two projects too...

BTW, for the crossbow, did you try using latex tube instead of paracord? I think It will enhance a bit.

[dbull]

I didn't think of that, but I may try it. The more I use it, I am sure I will be thinking of tweaks to the design. thanks.
Your spinning top is cool, I wish I had a lathe, it is one of the few tools I don't have in my shop.