Instructables
Picture of Ballbearing Crossbow

My cheap crossbow broke, so I decided to make a wooden one using the left over parts (limb, trigger mechanism and foot stirrup) that could fire marbles or ball bearings by having a top barrel so the bearing doesn't jump out.this is my first instructable and im also writing this in hindsight; meaning i've already made it. this is more of a guide to the layout not strict instructionWARNINGIf you plan on making one of these you should treat it as a normal crossbow. NEVER POINT IT AT ANOTHER PERSON OR LIVING THING!I made this for target practice and for fun but a ball bearing could be potentially lethal! obviously bear in mind that power tool and hand tools can cause harm so work safe! I take no responsability for any damage or injury sustained by making and using one of these!

 
Remove these adsRemove these ads by Signing Up

Step 1:

Picture of

So first of all you'll need some wood, I used sapele because I had some but you could use most hardwoods (bear in mind it will be under a lot of stress from the bow being in tension and then released so go for something sturdy like ash or beech if you can) the stock needs to include the distance the bowstring is drawn back, a handle or grip and the butt which is normally the lenght of your forearm.

Step 2: Layout

Picture of Layout
0.358863023853110420131207_025943.jpg
0.44155482685320120131207_025924.jpg
0.799443618652970120131207_025918.jpg
0.647524678283852520131207_025908.jpg

really the only critical part of this project is routing the channel for the marble so that it sits right and can roll freely while still leaving room for the bowstring. That and the recess for the trigger mechanism. in my case i had 16mm bearings and the string was 6mm thick so i made the depth of both channels 5mm with a 45 degree bevel on the inside.

Step 3: Shaping!

Picture of shaping!

using a spokeshave i rounded the edges and also cut a notch for the bow that i packed with leather to hold it steady.

Step 4: Changes/improvements

Picture of changes/improvements
temp_-993740126.jpg
temp_-2047291463.jpg

I planed the stock down to about 30mm thick, routed an ovolo to reduce friction on the string and made a longer barrel to hopefully increase accuracy.

Jonnis shed stuff (author) 9 months ago
Thanks for the feedback guys :-) next instructable probably wont be as dangerous!
antagonizer9 months ago

Reminds me of that Macaulay Culkin movie, The Good Son. Very neat.

boatingman9 months ago
Wow. I love this. I made a similar crossbow when I was about ten or eleven, from plans in the Book of Knowledge Encyclopedia. Great memories. Thank you.