Restoration of a Knabe Ampico Reproducing upright for Carol Drummond
1) 
2) 
3) 
1) Here is a photo of the piano before work began.
2) This photo shows the most obvious flaw in the piano. This became the focus
of my attention when I saw the piano the very first time. The glue joint which held
the pin block to the back supports of the piano had failed. This had allowed the
plate to bend forward, carrying the pin block with it. Happily, a careful inspection
revealed that the plate had not broken or cracked under the stress. Thank you Knabe
for making your plates hefty!! I was not expecting this problem when I went to see
the piano and had no tuning tools with me. However, Carol and I used our ingenuity
and found a way to release the string tension immediately before the piano was moved.
This prevented the chance of the plate breaking during the moving process.
This fault with the piano will entail a significant amount of extra work to set
right. However, it also did a few of my jobs for me. The first job that I
would normally have undertaken was to remove the portion of the lid board which was glued
to the top of the pin block area. This board had been severed from the piano by the
stress of the pin block failure. This photo shows the underside of this lid board
set along side the area of the piano to which it was originally glued. All the old
glue and torn wood will have to be removed and replaced before reassembly can happen.
3) Here, all the removable boards have been taken off and their hardware dismantled
so that they can be stripped of their old finish. You can now see the Ampico player
mechanism clearly.
4) 
5) 
6) 
4) The top part of the mechanism is now out. This is always a difficult job on
old systems because the old tubing has hardened and become difficult to remove. Care
must be taken to get the mechanism out safely. After rebuilding, it will be possible
to put the mechanism in and out of the piano much more easily.
5) The pneumatic stack and spool box assembly out of the piano and sitting on one of
my many work benches.
6) Now the entire player mechanism is out of the piano and placed on and around this
bench. It is often hard to believe that these mechanisms will actually fit inside
the pianos when you consider how much room they take up on the work bench!
7) 
8) 
9) 
7) The piano is now tipped onto its back so that the next step in taking it apart
can be done. The bottom board must be removed along with the board which houses the
pedals. Next, the front casters are taken out temporarily in order to reveal the
screws which hold the bottom halves of the legs secure. After these screws are
removed, the casters are reattached for ease in transporting the piano about the shop
during restoration. The next thing that has to happen is to remove the keybed.
This is the assembly on which the keysticks themselves operate. In normal
installations, another pair of screws are removed from the tops of the legs. Then a
series of heavy screws come out of the keybed and then the keybed can be slid from the
piano like a drawer. This is not the case with this instrument. This Knabe was
assembled differently at the factory. The original way the piano was made was to
construct the back assembly (which will shortly be revealed in this photo record.)
This assembly consists of the back wooden braces, the sound board, bridges, pin block,
plate and strings. After the back assembly (sometimes called the harp) was
assembled, the cabinet was preassembled next to it and then wrapped around the back and
glued into place. The keybed was never designed to be slid out ever again.
Since we can't take the piano apart in the way it went together, compromises had to be
made. The mission style piers at the ends of each cheek of the piano actually served
to hold the keybed in place even after all else had been removed. What's more, these
ends were attached to the piano with an extremely good type of joint. These blocks
had to be removed to get the keybed off. However, there was no way to safely remove
them without badly damaging the parts of the piano around them. It was decided that
the best way to proceed was to sacrifice these original blocks by splitting them off the
piano in sections which would preserve the surrounding structures. Later, exact
duplicates will be made and installed as the piano is reassembled.
8) The piano is ready to have the string sizes recorded and then to have those
strings removed. The reason that loose strings are hanging everywhere is due to the
emergency conditions under which we removed the string tension from the damaged piano.
The wire coils that held the strings tight had to be broken with a chisel since
more appropriate tools were not at hand. This left some wire hanging.
Normally, I would never proceed with this part of the process in such an untidy manner but
there was no choice in this case. Better to have some wire flapping than to have a
broken plate by the time the piano got back to the shop.
9) Here, you see the keybed after it had finally been successfully removed from the
piano. One other thing that was unusual and had to be compromised was the way in
which the legs of the piano were affixed at their tops. Instead of the standard
screw holding them in place, they were held with dowels. It became necessary to use
spreader clamps to spread the leg support blocks away from the keybed about 1/16" so
that these dowels could be exposed. They were then cut carefully so as not to damage
the surrounding structures. When putting the piano back together, I will probably
use a more standard screwed together arrangement for this joint.
10) 
11) 
12) 
10) The strings are now off the piano. Now the wiring buss which is housed in
a metal conduit will be removed from the piano. All the original metal components
are in good order as are the ceramic and bakelite fixtures. I will take all those
apart and run new wire through them during the rebuilding of the player mechanism.
11) Removing the tuning pins. Many of the things Knabe did in building their
pianos were very, very good. One of them is the use of plate bushings. These
are wooden rings which are driven into the holes in the plate which will house the tuning
pins. The tuning pins are then driven through these wooden rings into the pin block
behind. The use of plate bushings adds extra strength to the assembly that would
otherwise not be there. During the restoration we will remove the old plate bushings
and install new ones.
12) Removing the bridge pins. New bridges are slated to be made for this
piano. This is a good thing since careful inspection reveals that these bridges are
in such horrid condition that repair of the originals is impossible. We will make
new vertically laminated bridges which will exceed the quality of the originals vastly.
This is one area where Knabe consistently dropped the ball with their quality.
Vertically laminated bridges were not used. In addition, the cap of wood
glued to the tops of the bridges to make the notched areas clean, crisp and strong were
always too thin and the grain oriented in a way guaranteed to sabotage the longevity of
the bridge. The bottom line is that, despite a vast number of excellent building
techniques which make Knabes some of the best pianos in the world, they have constant
problems with pin blocks failing, bridges failing and some lids breaking because of bad
wood grain orientation. As a further example, if you take note of the rebuilding of
the Victorian Knabe grand for Don Hollingshead going on at the same time as this project,
the lid was so badly broken that a new one had to be made. In the cup, you can see
the old bridge pins which have been extracted. These are taken out for a number of
reasons. It is easier to make a pattern of the bridges if the pins are out.
Also, the bridges are safer to work with when the pins are out. Pulling out the
sound board and removing the old bridges, then transporting the bridges about the shop is
an invitation to getting your fingers cut when all the old pins are still in place.
13) 
14) 
15) 
13) The plate is now out of the piano. The red color of the top piece of wood
(the pin block) is chalk. This was used as an aid to fit the pin block to the plate.
In fact, Knabe did a fairly good job of fitting this piece of wood to the plate.
The wood is, in and of itself, in great shape. The only problem is that the
glue joint has failed. I will reuse the bulk of this piece of wood. Recesses
will be routed out of the block to make places to insert new delignit pin block segments
to replace all the wood which surrounds the new tuning pins. However, an entirely
new piece of wood is not called for hear.
14) The plate, after it was extracted from the piano. Some of the screws along
the treble edge were so close to the side of the piano that they nearly wouldn't come out.
This is further evidence that this assembly was constructed separately from the
rest of the piano and then the case of the piano was attached to the harp later. I'm
sure those screws will be equally fun to put back in later!
15) The pin block is now out of the piano. To extract the entire pin block
from an upright piano usually involves jigs mounted to power tools like chain saws.
The process trashes the pin block completely and requires that all new wood be
installed. In this case, I was able to remove the pin block by hand without so much
as a chisel because the glue joint had totally failed. What's more, the joint failed
completely and all at once. No signs of warping or bending are apparent in the
block. If the joint had slowly failed starting at the top, the block would show
signs of warpage; which it does not. Upon close inspection, it would appear that
part of the reason for this failure was that Knabe was not very liberal with the glue when
they originally assembled this. In order to ensure that the block is glued in better
than when it was new, all old glue residue will be soaked from every surface that faces a
glue joint. In addition, the new pin block inserts will be cut and installed before
the pin block is reinstalled into the piano. One possibility that I have entertained
is that this damage to the piano may have happened suddenly as a result of the piano being
dropped during an amateur moving attempt... In any event, I will probably add
additional steel supports that pass clear through the entire plate/pin block/back assembly
in order to sandwich them together and prevent any shock or stress from every bringing
this glue joint apart again.
16) 
17) 
18) 
16) When the pin block failed, the weight of it came down
hard on the rastin. This is a ledge of laminated wood which supports the edges of
the sound board. This meant that this support board came unglued as well due to the
shearing force of the pin block coming out of alignment. The fact that portions of
this rastin were lose made it extremely difficult to remove the old sound board while
maintaining my index marks which will assist me in making the new board. With solid
rastins, heavy blows with a large board strategically placed around the edge of the board
from the back will slowly loosen and then dislodge it. In this case, I had to add a
lot of chisel work and even more strategic blows to get the board out. In addition,
the board incurred serious damage in removal. This is not unusual for boards which
are in bad shape but this one really got hammered because of the condition of the
surrounding structures. The board will have to be carefully taped up to maintain its
original shape so that various index marks and access holes can be transferred to the new
board accurately.
17) Here, you see the piano with the sound board removed. The next step is
going to be to clean up all the dirt and debris and then soak and chisel off all remaining
glue residue and wood fragments left throughout the pin block and sound board areas.
This will get them ready for the repairs which will ensure a solid sound board and
pin block installation which will last us another century.
18) A picture of the back of the sound board after it was removed from the piano.
19) 
20) 
21) 
19) This shows me indexing the bridges by drilling holes
through the sound board into the backs of the bridges. Also, I'm drilling out the
dowel rods which passed through the ribs into the bridges. This will enable me to
remove the bridges without tearing up the old sound board too much. Although it
won't be reused, I need it to make a pattern for the new board.
20) The pin block has been removed from the piano. The main posts and spacer
blocks which back the pin block up have also come unglued in many areas. In this
photo, those glue joints have been put to the test. I intentionally severed as many
of the joints as I could. Any joints which were still extremely strong, I left
alone. The rest will get reglued but I have to open up the joints to clean them out
and put in glue first.
21) Using a hand plane to remove splinters of wood left behind by the lid board
where it glued to the pin block. This will give me a nice clean joint to glue the
lid back down.
22) 
23) 
24) 
22) Here, I'm using water soaked paper towels strategically
placed to remove all old splinters of wood and glue residue from every joint which must be
renewed.
23) Here, the back and sides of the pin block where it glues to the piano is being
soaked as well to remove all traces of old glue and wood splinters. If the old glue
were left in place, the fresh hide glue would probably partially melt it and cause it to
bond anyway. However, it would be impossible to get as tight a joint or as strong a
joint without removing every trace possible like this.
24) During the process of cleaning up the rastin (the shelf the sound board glues to)
and pin block areas, many of the segments of the rastin had their rear glue joints show
signs of failure. Therefore, I went out of my way to soak off all boards whose glue
joints were anything less than perfect. Then those boards were thoroughly cleaned of
all glue residue in preparation for being glued back in place. This photo shows just
how many separate boards had come unglued. Obviously, this piano has been subjected
to some terrible moisture levels which will need to be monitored more carefully in the
future after the piano returns home.
25) 
26) 
27) 
25) All of the glue joints for the pin block, sound board to
rastin and rastin to back frame have been thoroughly cleaned and are ready to have their
various components reglued to them.
26) First, I had to pour a very large quantity of glue down inside the joints to the
back beams which were opened but could not be totally dismantled. This glue was
mixed to dry very slowly and to be quite runny. This enabled it to have time to
rehydrate any glue residue that was missed inside and to penetrate every nook and cranny.
Once I was satisfied that every square inch was well coated with glue down inside,
many clamps were laid on to bring the joints back together in proper alignment.
27) This photo shows the case after the old varnish was scraped off. Later,
the residue left behind will be washed away with thinner to bring the wood to a clean
state ready for new finish.
28) 
29) 
30) 
28) The white pieces are a jig which was custom made to fit
this piano to make new inserts for the pin block. After the inserts are completed,
the jig will be thrown away since it won't fit any other piano. By using this jig, a
router can be used to clean out a recess in the old pin block to receive a new thick block
of Delignit. This is a modern pin block material which is very good at hold tuning
pins tight for decades. It is far superior to what the piano had when it was new.
The negative halves of the jigs are cut from the positives. The other halves
are used to guide the router in shaping the new Delignit to fit the recess very well.
Later, these will be indexed into the recesses and the plate reinstalled so that
the holes in the plate can be transferred onto the new wood for drilling at the bench.
After drilling, the inserts will be epoxied into the piano.
29) Getting ready to glue the pin block back into the piano. The recesses were
cut into it before it was glued back in so that the job could be done better and more
easily. Usually, we do this job with the block still in the piano which is much more
difficult and sometimes requires special techniques to get new wood around the outer
edges.
30) The pin block is glued up and clamped firmly into place. The new wood
inserts are in place temporarily so that I can get pressure onto the back of the pin block
in the areas behind these inserts.
31) 
32)
33) 
31) Gluing all the rastin boards back into their correct
orientations. The pin block had to be glued in first before these boards were done
because two of them glue both to the back frame and to the lower lip of the pin block.
That is why the clamps are arranged in two plains. One is to pull the rastin
toward the back frame and the other batch to pull it into the lower edge of the pin block.
32) Transferring the tuning pin and plate screw locations to the pin block
inserts.
33) Drilling out the inserts at the drill press.
34) 
35) 
36) 
34) Getting the action ready to be torn down.
35) Removing the damper levers.
36) The action has now had all its original parts removed. I will be replacing
all action parts on this piano that can feasibly be replaced. Some of the parts are
such that exact new replacements are not available. In these cases, I will clean and
restore those originals so that they will be reliable and high effective before assembling
them with the new parts. When I am finished it will probably be difficult to tell
the difference between any part which I had to recondition and the new parts they will
look that good.
© Copyright 2010 {David Rodgers' Piano Rebuilding}. All Rights Reserved.