Hey Cranky, From the "...the place of the wealthy hardware man" ACE Hardware. They were actually reasonably priced. Like $3.00 each. I figured they were going to be more like $6, but to my surprise.
While you are there, I'd pick up either a 1/2" drill bit,or a "UNIBIT" that goes up to 1/2". The saddle of the clamp is perfect, but the size of the U-bolt is WAAAYYYY overkill. One could hold a car up. Also, like I had mentioned before, the threaded part that sticks into the box takes up some room. With some time and a grinder (abrasive kind) I could trim them down, but I just stuff stuff around them.
My bags are used for holding the parts and extra oil, so it's not like I'm putting and pulling stuff in and out all of the time, so I've been living with it.
That's my excuse for not wanting to get set up to grind.