The Shrunken Dungeon: Dice Catapult

This prints just fine with standard settings. You will have to set a pause print somewhere around the 6mm mark to insert the hair tie into the tension posts, I recommend stretching the hair tie a bit and taping it down with masking tape as seen in the pictures. 

The 2 m3x16 screws are just pins for the tension posts, these are required for proper operation. You will defiantly want a rolling tray with this.

To set up the dice catapult, put the tension posts in the square holes so that there are no twists in the hair tie. Place the screws in the holes so that they pin the tension posts in place. Pull the slack from the hair tie to the front side of the catapult. It should look like the following picture at this point.

Make a loop in the loose side of the hair tie.

Pass the end of the scoop under the back part of the hair tie and through the loop. The way shown works well for standard dice but you may have play around if you are using heavier dice like metal.

Slide the end of the scoop into the socket in the base.

Finally, push the hair tie loop up into the notches on the scoop.

Hardware 

Hair Tie

2 m3x16 screws

Altoids Tin

Rolling Tray