Herrburger Brooks spring & loop action

[Alan Forsyth]

This is a multi-part message in MIME format.

---------------------- multipart/alternative attachment
Jon or Noj asked;


"Anyone out there familiar with this action? I have no info on =
regulating procedures or specs. I tried some addresses in England to no =
avail........"

There are 2 types of spring and loop action.
The older version is generally referred to as the "Costa" spring and =
loop. This version can be found in pianos made in the 1880's to 1895. It =
is basically a modified version of the original sticker action, but in =
this case the sticker is the jack, check,damper lifter and whippen all =
in one. In essence, it has 2 moving parts instead of 3 as found in the =
tape check action not taking into account the damper assemblies. The =
whole (jackass- embly) is connected to the hammer butt via a spring from =
the jack to a loop in the hammer butt. They are an absolute pain to =
regulate if the spring tension, length and thickness is incorrect. The =
single spring has to do the equivalent work of the jack spring, butt =
spring and tape. If this is the type you are referring to, just scrap =
it; it is just not worth bothering about unless all the springs are =
present and in good condition. Otherwise the specifications are as per =
normal i.e. set-off, hammerblow, check distance. You will find though =
that the hammer flange assembly is mounted flat instead of vertically, =
so if you need to travel the hammers, you use packing under the flanges =
instead of casting the shanks.

The second version is a normal tape/check action that appeared to have =
been discontinued around  1910. You will probably only find them in =
overdamper actions that were common here. I have had to deal with quite =
a few old German pianos that have this type, the name of Rud Ibach comes =
to mind. Here a long spring is used as both the jack spring and the butt =
spring. You regulate them as a normal upright action, but again if you =
have to replace the springs, they have to exactly match the originals. I =
do not know what the specific tensions are supposed to be and I doubt =
whether anyone alive knows. Generally, the cost of overhaul way =
surpasses the value of the instrument so the need to know specifications =
is not an issue. I usually advise the customer that such a piano should =
only be restored for semi-mental reasons, as I put it. Regulation is =
just as normal.
Assembling the parts can be tedious as it is quite tricky to thread the =
spring through the loop. It's one of those jobs that requires 3 =
hands,...................................................... and a few =
more balls.

AF







---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/c7/a7/15/c6/attachment.htm

---------------------- multipart/alternative attachment--