I'm with kicks all the way. I have the one that has the springy point on in the middle of the cutter, and as Vaughn says you have to make a pilot hole. I now use a good quality sharp 3/8" with not a lot of pressure. If I can I slip a screw driver between the pieces and give it a little pressure so that it "pops" up when the first layer is cut through. I saw one that I thought was well done, the fellow had ground the cutting edges of the bit so that there was a little point (1/16") in the center of the bit sticking out and acted like a pilot drill, not sure how he ground it though. Worked well and when the point got dull he just reground it.
