Hi,
One of the things I always wanted to do with my CNC, was a medieval crossbow. I made everything myself except the fiberglass bow and screws.
Here are the pictures in 10 steps.
The Crossbow is designed in Fusion 360. It took a lot of learning to get it right. I’ve only been working with Fusion for about 6 months, and those “gun stock” curves kept getting wrong.
First thing was to top flatten some Ash tree.
Then it was time to cut the two parts for the crossbow body. This is the right side.
This was my first time trying to make a two side cut. First I had to cut the inside holding the trigger and roller nut. Then the outside curved profile using a straight flat end mill followed by a ball end mill.
Then is was time to make the roller nut. To make it strong enough, it’s made of three pieces of aluminum and two pieces of ash. The extra hole offset from the center hole, will have at pin inserted. This will make sure the pieces are kept in place together with some superglue between the pieces.
This is the inside showing the roller nut and the trigger. Later I added a spring, that kept everything in place.
This is the part that holds the fiberglass bow in place at the front of the crossbow.
Now I had all the parts for the crossbow, except the bow string. I used my CNC to cut out the parts to make a Bow String Jig.
I also made a bow string serving tool (first thing not made on the CNC 
)
This is the finished “continuous loop bow string”.
And finally the assembled and painted medieval crossbow
