Picture of 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

Picture of 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. 

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
Ruler/ Tape measure
Drill bits
Box Knife
Round file
Coping Saw
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.

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MattC104 months ago

Your attempt to explain the construction of the torsion springs (Step 7) is rather pathetic. It does not offer a clear explanation of how/where to begin or end the spring cords. Do the ends hang loose? That would unravel the spring. It offers little assistance to the casual reader. Please consider adding more detail.

mikeyvans MattC102 months ago
MattC10 mikeyvans2 months ago
Ah. I appreciate your absolute abandonment of the art of disagreeing, preferring instead to resort to vulgar, childish name calling. Thank you, sincerely, for adding absolutely nothing to the conversation.
mikeyvans2 months ago
This is awesome I'm sooooo adapting this design into a longbow size design
terrefirmax26 months ago

I love reading all these inspired projects and seeing the (mostly)supportive comments. I feel frustrated that I have a garage full of tools and wood and other supplies and no one to utilize them. Even I have a hard time getting started because there's not good organization of everything. My family would like me to just get a dumpster but I have old heart pine 2x4s and beams and bolts and hardware just aching to be turned into something in the right hands. I have tried offering a rental house I own for free to a local hackerspace but after leaving me hanging for months they rented a bigger space. I just want to expose kids and adults to doing and making that maybe don't have the place or resources on their own. Any thoughts on how to connect? ps. Organization is not my strongest suit.

warthur6 months ago

just asking, why the lever trigger instead of a roller nut?

This is brilliant, possibly one of the best things i have ever seen. I have tried building my own crossbows before but i could never source an effective prod, well good enough to hunt with anyway. This is the ideal solution to my problem, how powerful is the crossbow?

jerseyman2 years ago
Hi dbull
I'm in the process of making the scorpion , having trouble downloading the stock plans could you give the length and with of the stock and barrel . Thanks Ron
This is SlenderMan.
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
While we're getting all technical the projectiles crossbows shoot are generally referred to as bolts, not arrows. A scorpio is a type of a crossbow too so the original author was technically correct. Actual scorpios all have mount stands.

Great article by the way.
he said that in the title
Yes he changed it after I informed him.
dbull (author)  skelly74474 years ago
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 (author)  Electroinnovation4 years ago
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.
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 (author)  Electroinnovation4 years ago
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
Sounds good, thanks.
Okay no problem
anibioman3 years ago
im going to make this but a dumbed down version as im a beginner.
darthbindy3 years ago
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!!!!!!!!!!!!!!!!!!!!!! =)
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!
i built one of thes out of wood pallets
armourkris3 years ago
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.
jschap13 years ago
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?
bwells24 years ago
Can it kill game?
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!
sweet. 5/5
sooo trying this but made out of steel and using metal springs
this is so good thnks heaps
bowmaster4 years ago
Hunting with miniature siege weapons? Sounds like a good time.
bombmaker24 years ago
Do you think the size could be doubled without making the top and bottom pieces thicker? Or do you think everything should be doubled?
skimmo4 years ago
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
omnitron4 years ago
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 (author)  omnitron4 years ago
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 dbull4 years ago
thank you
skimmo4 years ago
this is pure epic win!
popa272724 years ago
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 (author)  popa272724 years ago
Yeah, I went through a few designs before thinking of the tighteners...I wanted to avoid the problem you had.
brando14 years ago
can you use bigger rope
dbull (author)  brando14 years ago
are you asking about the strings for the springs or the rope that pulls the limbs back?
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