Hi Terry. Welcome to the forum. This link will take you to the Cat website for the 621. To bad this one doesn't have a decent drawing as we usually just scan it and have it enlarged to the size you need. Might find you 1/2 or 3/4 square at home depot or Metal supermarket. Hope this helps. Rob
http://xml.catmms.com/servlet/ImageS...mageId=C198833