OK, I know this topic has been talked to death, but I wanted to share what I found out about the problem I was having with the blades. I ran out and bought a bunch of the blades (like so many quilters and sewers did) and couldn't get them to cut after the first try. I put them away and carried on. Finally, I started to use my rotary cutter with another blade and it wouldn't cut very well. To make a long story short, after checking some stuff out, I found out my cutting mat was shot. So, I bought a new one and low and behold, the Harbor Freight blades work great! So, if you are having trouble, check your mat, it might be the problem.