I just installed a new sink and faucet and get really bad water hammer when I run the faucet. I never had this trouble before. I made sure the water supplies from the copper to the faucet is as short as possible. How can I fix it?
With the water running, and presumably making the noise, put your hands on the copper pipe - can you feel the vibrations? Does it go away if you hold the pipe? (Be careful of the hot water pipe - it can get, well, hot)
It could be that the pipe is simply loose.