Key Pin Friction - was Heavy Playing S&S C

[Newton Hunt]

This is a hand job.

First move a key sideways and move it up and down, forcefully, and if there is drag
then the pin needs polishing or there may be burrs on the pin.  Polishing should be
done with real fine polishes like Flitz or similar polishes.  Brasso is too course
and does not leave a durable polish behind.  Messy also.

Once all the pins, front and center, have been polished and lubricated and the
bushings have been lubricated with a dry Teflon spray or Prolube then fit each key,
one at a time, onto the frame.

First check the fit of the center pin to the bottom key hole.  Enlarge as needed with
a hole easer from the top of the key.  Supply houses sell the appropriate tool for
this.  It is best to have the key fall slowly into position than to have it drop down
fast.  

Second make sure there is a minimum of free movement of the pin inside the button
bushings.  Ease these gently and carefully for one over eased there is no recourse
but to rebush.  Grasp the button and move it left to right and watch the bushings and
pin to gauge the movement, about .2 mm.  You want the key to just barely be free.

At the front of the key move the key left and right at the rest and depressed
positions.  There should be about .3 mm at each position.  Then gently move the key
and and down and feel for any drag or snag and correct as needed.

When the last key has been eased and installed on the key frame the job is complete
and will not need to be attended to again during the regulation process.

It is the details that count and working with each key until it is perfect that makes
for a completely dependable job.

		Newton