S & S 'D' Problems

[Richard Brekne]

Hi Avery, read this and a few other posts and I have a few thoughts
below.

Avery Todd wrote:

>  List, I've talked to the shop tech and he told me that he'd had to
> raise thestack some because the hammers weren't hitting correctly. My
> firstquestion is what effect would that have to how the action would
> thenhave to be regulated?

I almost wrote out my thoughts last night, but decided to check them
with an action model this morning at work. If you just raise the stack
and do nothing else, the whippen is going to drop relative to the stack
to meet the capstans. This causes a change in a few angles and a few
centers distances, and one of the results of all this is that the
hammers drop lower relative to the Keys/ Back checks. So that you report
that the hammers are resting on back checks, this shouldn't surprise
really.

I wanted to also ask what about the hammers hitting was wrong, and you
mention over centering. Seems to me that this then you need to know
whether the hammers were actually hung wrong to begin with, or if the
stack actually needed raising.  If raising the stack was an answer to a
poorly hung set of hammers then its not really the right thing to do ...
or what ? What's the rake and the bore length suppose to be on a  New
York D ?. What's the distance between the hammer shank center and the
string height ? Isn't it such that with the shanks parallel to the
strings the hammer should be just touching the strings, and if the rake
is correct also at the proper point ?

A few other things... Moveing the stack will also increase the differnce
between the letoff button and the jack tail. The whippen drops a bit but
the hammer rail follows the stack completely.  With the same key dip as
before, same capstan height, and same letoff button setting, the Hammer
will have an increased strike distance and  increased lettoff distance.
If you then adjust for proper letoff, you are not going to have enough
key dip / aftertouch... so a few punchings could be removed to fix this
resulting in a 10mm + dip, a 2 inch blow, hammers resting on backchecks,
and I think (tho I will no doubt have to think on this all
evening...grin...) slightly increased leverage resulting in a bit
lighter touch. If you have too much drop, that fits as well... as it
would be neccessary to raise drop screws and that might result in them
draggin on the bottom of the pin block, or needing to be up higher then
then actually can effectively be regulated (you can check easily to see
if they are at this point by just looking at them)

Anyways.... just my thoughts on the matter. If anyone can shoot holes in
my reasoning... please... by all means do so. Neat to try and think
these kinds of things through from afar.

Seems to me tho, from what you wrote... that the hammers were hung
wrong, and thats what needed addressing, not the stack.

>   Regards,Avery P.S. At least they corrected some of the problems with
> the damper lift,even though I don't really like the damping, either.










--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html