This is a piece of crap! Don't waste your money! I wanted to drill 6 holes in wooden planks and used a 6" hole saw. . I knew I couldn't drill all the way through because the hole saw was too flat, so I had to make one side and then go over the other side. It's WOOD and not even solid wood.I used the lowest speed on my drill bit and this junk kept starting to open up so I eventually had to use some serious tools to tighten the mandrel but after my first hole was done.In the middle of the 2nd Lochs I noticed the teeth were getting dull and NO I DID NOT TURN THE DRILL BACK BACK like some idiots do.This set is good for cutting butter,water and pudding.If you want to cut other materials buy it you a real hole saw.