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MMD > Archives > October 1997 > 1997.10.21 > 16Prev  Next

Rebuilding the Autopiano
By Craig Brougher

Sam Harris was asking what he should expect to find in an old, pristine
Autopiano he is undertaking to rebuild.  They are big, heavy actions with
double valves and should have no real mechanical problems with the
exception of one thing: Valves.

I always replace everything in every valve-- al the soft working
materials go.  There is no such thing as saying, "Gee, this looks like
new-- I think I'll just leave it in." It's all just as old as everything
else there, so it will be the first to rot out after the rebuild.  That
isn't the problem you want to leave in your piano, I suspect.

When you replace pouch leather, it is very important to first tape it
against a window and mark all the pinholes with light streaming through
them.  Thin areas will be evenly lit like rice paper or something.  mark
them out.  The rest of the skin should not be used if it "mikes" thicker
than .010.  Put the thinnest of the thin into the primary chest.  Seal
with something like the Dow Corning 111 grease, thinned so that you can
brush it on.  Wait for it to thoroughly dry before your pronounce it
tight.  Often, you have to add another coat.

The most common problem with Autopianos are the valve stems which are
threaded.  The valve leather itself also threaded, and the acids in the
leather often weakens the thin threaded rods so badly they are almost
ready to break.  These you can replace with the Auglaughoff threaded rod
of one variety or another from Organ Supply Co., Erie, PA.

The valves can be made from soft, thick calfskin with a pin hole in the
center.  Thread them on dry, first, then I usually put a drop of very
watery hot hide glue at the threaded leather hole, which is wicked up by
the leather.  Straighten each valve and stand them in holes until
completely dry the next day or so.  As soon as they are dry, break the
glue seal and they will thread up and down the shaft to adjust, just like
they had been tapped with a threader.

Regarding the very low cost for all the work that you are prepared to do,
I would suggest that a seasoned rebuilder will be spending at least 160
hours on the player mechanism alone if he doesn't make any mistakes and
knows, from one operation to the next, precisely what he's doing.  If
this is your first one, you may as well plan on spending three times that
long, unless you sort-of give up and start cutting corners, getting
frustrated and saying, "Oh, that looks ok-- let's just let it go," and so
forth.  Everything you fail to do, to test, to measure, to check out in a
player comes back to haunt you.  You won't be happy.

If a player is anything, it is valves.  Any rebuild that has not redone
the valves completely is called a repair.  The difference between a
really great repair and a complete rebuild is several more weeks of work.
It is also the difference between a player that plays just great for
about 5-10 years and quits playing, and a player that is a family
favorite, has a lot of rolls, and is still being played in one of the
children's homes 30-40 years later.

Craig Brougher

(Message sent Tue 21 Oct 1997, 13:33:26 GMT, from time zone GMT.)

Key Words in Subject:  Autopiano, Rebuilding

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