I can't add to what has been said above, but I will confirm it. Make sure the blade is 90 degrees. I did a puzzle where the blade was just off. Some pieces fit in front and other fit in through the backr. Don't push the blade because it will bow the blade. I would suggest starting with 1/2" thick wood. It is a little more forgiving on blade deflection and if the blade is not perfect 90 degrees. I use a #5 blade on 3/4" and less material and a #7 blade on thicker stock. Puzzles are a great way to practice following a line. No one notices if there was blade drift.