check to make sure the needle is in correctly and all the way up as far as it goes before you tighten the screw. my machine won't allow me to put the needle in backwards but some do. Also slowly use the hand wheel to lower the needle to see if it might be hitting on something when it comes down. The tension would have to be mighty tight to break the needle. Most likly that it is hitting something by either not being all the way up in the shaft or when it comes down it's there is a problem with the needle plate. Also try a different needle; maybe it's slightly bent.