Duysen Grand

[Richard Brekne]

Hi guys and gals..

This action is in for repair. Duysen grand from 1913. The action is
manufactured by Lexow of Germany. Action number 566522

Here are some  present specs before doing anything. Hammers are severly
worn and it plays very heavily and clunky. The hammer bore length and total
lengths are 50 / 80 mm treble, and 56 / 86 mm bass. Knuckels are 10mm
diameter and 16.8mm from the hammer shank center. Capstans are at 90
degrees from the keys. The action spread is wide.. 5mm at the top and 3mm
at the bottom. This has been moved at some time as the indents from the
washers on the whippen rail show also these exact differences. I assume
this was an attempt to get a lighter touch to the action at some time.. but
who knows.

Stanwood measurements as is yeild the following.

Key    1,    15,    25,    26,    38,    48,    49,    59,    67,    68,
77,    85
SW   11.3  11.5 10.9  10.6   9.5   8.6     8.6    8.1    6.9    7.0
6.5    5.8
WW  18.9  19.3 19.7  19.1 19.5  19.1  19.4   19.1  18.8  19.1  19.5  18.5
FW   21.6   21.3 16.3  19.9 17.1  12.9  10.1    9.8    6.7    1.0   -1.8
0.9
KR     .59     .60   .59    .62   .64    .62    .60    .60    .63
.60     .63   .60
UW    30      35     40     35    35     34     35     35     31
33      28    30
DW    69      64     60     60    52     48     48     46     46
43      38    36

As you can see there is little or no friction. This is due to very loose
centers no doubt. I checked a few and they averaged about 20 swings. Moving
the whippen rail in will probably give a bit heavier UW / DW readings, I
will do that tommorrow evening and post the changes.

I also noticed the odd numbers on the hammer bore. I will have to bore
myself if I am to follow these figures. Somehow or another I had the idea
that the knuckle was supposed to be around 10mm from the hammer shank
center. I measured a few spares I have laying around and the figure of
around 17mm seems about the norm. So I guess thats about right. The KR on
this seems very suspect and I expect that this is one of the real culprits
here. Moving in the capstan about 10 mm gives readings down around .54
which is more what I would expect as a max ??? or what ??. Doing so would
also bring in the WW numbers down to around 17 grams. These would combine
to give a Whippen Balance Weight of just above 9 grams which seems to be
standard for Standwood schemes. At present it is a bit over 11 grams.

I will be changing hammers,  knuckles, and centers and correcting the
spread amoung other things. The owner has complained about this always
being a bit heavy so I want it so be a good deal lighter, without over
doing things. My guess is that a BW spec of 38 with a SW ratio of 5.7 might
be a good choice... tho admitedly I am guessing at this. Its an old piano
with a hint of thining soundwise. Piano is solid tho.. no cracks anywhere
to be seen tho I didnt check crown. I have to go out there to get the
string height measurements so I can do that at the same time.

Looking forward to comments and suggestions. Hope a lot that there will be
some interest for all this.

--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway