Shallow repetition

[Newton Hunt]

Center pinning.

Carefully check the pinning of the hammer flange, rep. lever
support, wippen flange and jack center.

The hammer, held horizontal should swing down past lowest point
seven times.  Eight or six are acceptable but barely.  If these are
white teflon bushings then six is the only acceptable count.

There absolutely must be some resistance at the repetition lever
support center.  Disengage the spring and see if it will drop of
it's own weight.  If so repin so it requires but a small amount of
pressure to move it but not much.  A 1 or 2 gram weight on the drop
cushion should be sufficient.

Wippen centers should be loose enough that the wippen will swing
one time while the action is set so the wippen flange is up and
horizontal.  Too loose or too tight repin.

Jack centers should be only tight enough that the jack will slowly
move when the long arm is horizontal.  Repin as needed.

Work on only two or three notes and make them as perfect as you can
and have the customer test those notes to see if the problem has
disappeared.

Regulation.

Too much drop can cause such a problem.  The drop should be 1 mm
below let-off, no more.,

Some actions may require 11 mm of dip.

Backchecking should to set as high as possible, 15 mm or less.

Rep. lever height should be set so the jack can move in and out
from under the knuckle with it just barely brushing the nap of the
leather.

Jacks should be set so the back edge of the jack is in line with
the back edge of the knuckle insert.

Key bushings need to be free, no resistance but no excessive
movement, .3 mm front and .2 mm center.

Keypins and capstans should be polished with really fine metal
polish like Flitz made in Germany.

Key  bushings and key pins should be lubricated with a dry Teflon
spray or powder as should the capstan contact area and the knuckle.

Action performance is not one single element but the cumulative
effect of careful attention to the minutiae of every aspect of an
action.

No rest for the righteous.

		Newton