BCing

[Newton Hunt]

Hi, Tom,

The best test of the angle of the backchecks is to place one in check
and then tap on the strike point with the force of mf.  If the hammer
does not move the angle is too acute.  If it passes through then the
angle is too abtuse.

Check the length of your tails.  If they are less than one inch
(unlikely with Blues) then that is the problem.  Angle then is super
critical as is the curve of the tails.  Radius of the tail should be
between three and four inches.

Steinway invariable sets their BCs to high.  Optiumum height should be
level with the top of the hammer shank when the hammer is at rest
(regulated) and slightly below the tail end when at drop.  Ceck the
angle then try the height and recheck angle as see how it goes.

I am assuming that when you glued on the new leather you got the grain
oriented so the nap allows easy movement of the tail downward but
catches on it on the way out.

Backchecks should be no rougher than a clean piece of 80 grit paper will
make it.

IF the tail has a charp edge at the end you might round that over to
help preven early leather wear and help checking.

Tails should engage the backcheck in the center and parallel to the
hammer heels.

                                        Newton
                                        nhunt@jagat.com