If this banging is being caused by loose pipes and water hammer, you either have to secure the pipe better if you can get to it, add a wter hammer arrester, or try replacing the water inlet valve with a Fluidmaster 400A float-cup type. They only cost about $5-$6 bucks at a big box, and come with easy-to-follow illustrated installation instructions.
Good Luck!
Mike

 

Doesn't sound like water hammer. The drill-like chattering sounds like a bad toilet valve to me.

 

I agree, not your classic water hammer description. I was thinking a pipe through a stud that was not secured properly and was vibrating when the water flowed. I would try to locate the area where the sound is the loudest, by dragging an ear along the wall, and facing the posibility of having to open the wall up to secure the pipe. But before this, I think a few dollars for a toilet valve is definately a worthwhile investment, and I would even try completely draining down the house piping and opening all the faucets to let some air into the pipes. Many older houses do not have the sealed chambers that are used to prevent water hammer in modern plumbing. There would simply be a tee in the line and a 12" piece of pipe with a cap. Over the years, the air that is suppossed to be in this chamber is dissolved into the water, and the cushion is lost, sometimes leading to quite strange noises.

 

my vote is also be "bad toilet valve also"...

replace it ASAP before it is too late when all your pipes got beaten up... or hold yourself a bit longer to use the upstair toilet until you get it fix...