Bee-bot cart

The idea is not mine. You can find the Bee-bot cart with a Google search and buy it ready made.
I was in a hurry to get my hands on one of these for a kids robotics project so i designed one in solidworks and printed in PLA.
I have included two versions (big and small cart). I personally like the big cart better.
I have also designed two different wheel sizes.The 18mm ones fit better on the small cart. I recommend the 22mm wheels for the big cart.
The cart is designed for 4mm threaded rod, however depending on your printer accuracy,settings etc you might need to enlarge the hole on both the cart and the wheels using a 4mm drill bit.