Hamilton Beach 52184 12 Speed Blender

I've had this blender for a few months now but don't use it much. Actually I've only used it three times. The first time I used it to make chocolate milk for the kids using powdered milk and powdered instant chocolate it worked great!! I washed everything with soap and water and the next time I went to use it the blades would not turn. I soaked the whole blade module in hot soapy water, then sprayed with WD 40 washed again then soaked in hot water again and a few more times. Lo and behold it eventually loosened up. The next time I made the same beverage I took extra care to washing and cleaning the blade module. The same thing happened except now it doesn't loosen at all. Any suggestions? How does the blade attach to the part that mates with the blender that turns the blades?