This crosscut sled is quick and easy to make and can be made out of scrap material.
I used 9mm MDF for the base and runner and the fence is made up of 2 pieces of 18mm plywood glued together
Dimensions for my sled are 600 x 600 but you can make it whatever size you want.
I also took the extra step and added toggle clamps to the fence to hold down the work piece but you could easily make do without them. I also put some briwax on the runner to give it a smoother operation.
A quick and easy way to check if the cut is square as you see at the end of the video is by putting the two pieces together and flipping one piece over. Any error is then doubled and you should see a gap or light coming through the two pieces if the cut isn't square.
Feel free to ask any questions!