It sounds like the plastic nut is cracked
in the
string slot or is just too tight to let the string slip in and out. I
would try to take a nut file or emery board and make the edges of the
offending string as smooth as possible. Lift out the string and check
the slot to see if a small hairline crack is there. Also if there is
dirt or buildup in the slot clean all of it out. Reinstall the string
and tune. For the best sound change the material to bone.
Donated by: Tim Lawson http://www.timsguitar.com
I was experiencing a grinding or clicking sound about every half turn with my G tuning key. In addition, I wasn't getting the pitch change expected from the amount of turning I was doing relative to the other five keys. It's a brand new guitar with Grover Keys so I saw no reason for the poor performance and wondered if I was doing any damage to the nut or neck. I had a suspicion that the noise was caused by the G string grating against the nut and took this notion to the shop. They agreed with my assessment and said the worst-case scenario was that the nut hadn't been properly cut for this string, but that first I should try lubricating the nut to see if this helped. They suggested using powdered graphite lubricant available at auto parts stores to lubricate automobile key locks.
I squirted some out
on a sheet
of paper, scooped a little up on a knife blade, and
deposited a small amount in the offending groove (after loosening the
string and moving it out of the way).
This worked like a charm. Not only did the noise disappear,
but the machine key suddenly functioned as expected: a slight
turn, a slight pitch change. The next time I change strings,
I'm doing this to all six string slots in the nut as a preventive
measure.
And you don't even have to buy the powdered graphite. They suggested taking a razor blade or exacto knife and shaving some powder off the end of a pencil "lead", which is actually graphite and gives the same results as the store-bought variety. Only a small amount of the powder is needed, but any excess can be blown away.
I hope your readers find this as useful as I did!
Keep up the good work,
Barry Moore