knocking noise on sink faucet

[Blackhawk]

I have an 2nd floor sink faucet that has started causing a knocking sound in the wall when only the hot water is running. This started a couple of months ago. It is a two handle faucet and only the hot water side is causing the problem. It only starts knocking after the handle is opened past about halfway. The entire bathroom was remodeled about 4 years ago with copper pipe. The faucet is a high quality well known brand. After doing a little research on this forum, it sounds like this is being caused by a fluctuation in pressure in the pipes, which is not water hammer. If I understand correctly, water hammer occurs after a faucet or valve is shutoff. I read one thread that talked about the possibility of a faulty washer causing the pressure fluctuation. The water runs fine with normal volume up until that halfway point. Is the faucet really the most likely cause of the knocking? What signs should I be looking for inside the handle valve?

[HayZee518]

check the tightness of the valve packing and gland nut. the valve stem may be brass. as the water flowing through the valve heats up, the brass expands. the stem washer is about 3/16" away from its seat and acts as a venturi to water flow. a difference in pressure will cause a vibration.

[Redwood]

A loose washer will sound like a damn jack hammer.
do you know the make and model of this faucet?
post a picture if you don't know.

[Blackhawk]

The faucet is a Kohler model K-10270.

[Redwood]

That faucet does not use a washer. It has a ceramic stem..
Probably the faucet is not the source of the noise...

Look first at the angle stop valve under the sink.

[Blackhawk]

I actually turned off my angle stop a few days ago just to keep my kids from using the hot side. I just opened it back up and now the knocking is gone. I tried opening the angle stop 1/2, 3/4, and full and never got the noise. I am leaving it at 3/4 where I still get nearly full flow and see what happens over the next few days. It will probably come back, but who knows.

If it comes back, I will take the angle stop apart and see if I can find anything there.