Mechanical Music Digest  Archives
You Are Not Logged In Login/Get New Account
Please Log In. Accounts are free!
Logged In users are granted additional features including a more current version of the Archives and a simplified process for submitting articles.
Home Archives Calendar Gallery Store Links Info
MMD > Archives > May 1999 > 1999.05.21 > 11Prev  Next


Rebuilding Metal Stem Player Valves
By Craig Brougher

Because of the problems with players using the metal-stemmed valves
over the years which I have both experienced and troubleshot for
others, I want to offer this bit of advice to hobbyists who try to
rebuild their own.  This article is primarily concerned with actions by
Standard, Lester, Baldwin, Cable, Story & Clark, Beckwith, Hardman, and
the others which used metal stems and press-fit collars.

At the outset, The Player Piano Co. can be a good place to buy parts
and supplies, but it is not always the best place to buy valve leather
punchings unless you know what you are going to get before-hand, or
know what not to use (because they don't).  I recommend being suspici-
ous of their plastic coated leathers, plastic synthetics, neoprenes,
so-called patent leather (which is not real patent leather) and other
valve washers represented as better than leather.  Nothing yet has been
better than good leather.

When choosing leather for valves, I have never seen this rule fail:
Don't use any leather, either corrected calf (meaning that the grain
has been taken off the smooth side and the leather wax-finished), or
suede that you wouldn't want to wear.  It must be beautifully even,
reasonably heavy, supple, smooth, and have the proper stiffness, just
like the leather removed from the original player.

In metal stemmed valves which have a pressure fit collar for each valve
washer-- as in the Standard, Beckwith, and others, you also have a thin
metal washer backup plate which keeps the leather from "sucking up"
against the inside seat.  We could call it a "face washer." Without it,
the valve might never "let go" of the inside seat, if the leather were
supple and limber enough.

This has happened often to those who buy PPCo's leather valve replace-
ments for Standard.  Even with the thin shim washer, the leather they
sell presently is so limber and thin -- bodyless -- that it prevents
the valves from working.  I suggest not buying it.

Meanwhile, when you rebuild a player, you have to notice the little
things-- like, leather stiffness.  It is stiff for a reason.  It isn't
that way by accident.  Unless that leather was precisely that stiff and
very flat when punched and laid, that valve would not operate
correctly.

The leather in Standard inside valves was corrected calf.  It is about
.025 -.030 thick.  Shoe leather, some might call it.  It cannot be
patent leather, or it will stick on tin-plated brass inside seats.  It
cannot be soft, or it will stretch and distort, and will not release
cleanly.  And, it must be mounted the same way it was designed, with a
little flexibility at the valve stem.  That means, the valve washer has
to "tilt" slightly on its stem.  If it is too "tilty," then it will
leak.  If it is too "tight," then it will not seal reliably.  If it is
patent leather or slick plastic (today's stuff), it will not slide to
seal, so it will stick on the first spot it touches down on, and leak.

(This is not to discourage some Lester owners, some of which had
patent leather valves originally.  That was the real patent leather.
It was not vinyl coated and sticky to metal like vinyl.  It was also
heavy-bodied and flat.  They don't make it anymore.)

The next thing you MUST do in the case of the press-fit metal stem
valves, if you want a successful rebuild, is to back up your valve
washer with either the tiny leather seal, or a tight vinyl seal as sold
by the Player Piano Co.  Notice what comes off the stem.  There is a
little pouch leather washer about 1/4" diam.  It's hole is tight around
the metal stem.  The reason is because it alone is the stem seal for
the valve, allowing the rest of the valve poppet to tip slightly on the
stem for flexibility.

(If the total valve seepage of each valve in a player equals only the
diameter of a shirt pin, The overall leakage is a bit over what you
would have by drilling a 1/4" hole into your pump.  A few organ
rebuilders have had problems with this tightness requirement, because
they are dealing with relatively low pressures and huge, overdesigned
blowers to take care of leakages they always have.  Player pianos don't
have 1000% margin allowances.  They are designed for a smaller maximum
number of playing notes occurring at one time.  Above that number of
notes, they will drop notes.)

The next point is the fact that some player valves use metal backup
plates (the valve washer), and some use fiber.  Both will give you
problems, today.  Here is why.  The metal backup plates used by
Standard actions were tin-plated brass which reacted with the leather
acids to form a "vertigris," or green corrosion, which in turn makes
big green lumps under the valve leather.  Just one or two of these will
disable the player.  But you will have over 90 of them, any of which
will disable the player.

The fiber washer backup plates of similar actions are either red or
gray fiberboard.  They are worse.  They warp.  If you don't believe it,
then sit them down on a metal or glass plate and using a toothpick,
press around their circumferences.  They will almost always tip and
"click." That means they are not flat.  They may look flat.  They might
fool you.  Flip them over and check both sides.  If they seem to be
"evenly" cupped, they are NOT!! Put a dozen of them on a sheet of glass
or Formica countertop and tap with the end of a toothpick all around
the disk.  It will usually click and move around, meaning that it isn't
flat anymore.

Player Piano Co. sells both stainless steel washers for the two sizes
of Standard valves.  Those are the ones to substitute for the "face
washer", as well as the backup valve washer.  But for the actions which
use the fiber valve washers, be sure to throw away ALL red and gray
original fiber washers, and buy them from Organ Supply Co. in Erie, PA.
The Player Piano Co. in Wichita has discontinued those most important
parts.  I do not understand why.  It is their bread and butter...

(It would seem to me that if you are going to sell to a specialized
trade, you first must sell the things that nobody else wants to stock
for your trade, or you are no longer specialized.  But I am not a
merchant, so I guess I just don't have good sense in those areas.)

If your red or gray washers are "perfect," and do not tip on glass or
metal plate and are optically flat, congratulations.  Now throw them
away.  Because if they haven't warped yet, they will.  Thin fiber
washers of the original variety are the most insidious thing in the
valves of a player piano.  The tiniest warp cannot be remedied and will
cause even the cushiest valve material to leak, especially at low
intensities when you need tightness in a critical way.

The Beckwith player had a Standard-type player action, horizontal
valves, but used a thick, very heavy gray fiber washer for an inside
valve seat that was recessed in the valve chest.  When you unseal and
remove it, it warps.  From that moment on, it will not straighten back
up, regardless what you do.

The only way to fix Beckwith's fiber inside valve seats is to sand them
flat again on a belt sander, and then smooth them down.  I doubt that
you will find replacements for those, so we hope that the material has
fully responded to all the stresses inside it by now, and that it is
through warping.  But within a couple of days, it might be wise to have
gapped, sealed and seated all your valves in the stack again.  How soon
or if they decide to warp is anybody's guess.  Just be sure the screw
holes are tight to help clamp it again.

The tin-plated brass seats, stems, washers, and whatever else you have
must be cleaned up.  Then coat them with something like dry electrical
silicone spray (available at electronic supply stores) or TFE mold
release coatings to seal the brass against leather acids which
immediately begin on it again and start up corrosion.  Be sure that you
have removed all verdigris from the brass parts if you reuse them, or
it will grow quickly again to stop your player.

Any oil or grease, such as mink oil, Syl-Glide, Neatsfoot oil,
Vaseline, hemorrhoid creme, or whatever else they'll sell or recommend
for sealing and preserving valves is verboten in a professionally done
player stack having metal valves, because these oils are all lighter
than water and have a high vapor pressure index.  That means they will
redeposit themselves through the player.

When that happens, water molecules which travel with the air as
humidity are trapped under this molecular film of oil and together with
heat and the acidic moisture drawn from the leather, corrode all the
metal parts in this type of action, particularly in Southern climates,
and humid conditions.  Only pure silicone grease will stay put, and
will seal out moisture as well as cooking oils in the air, when you
lightly coat your metal parts with it, first.

Gap the valves between .035 and .045.  Anything under .035 is too slow
and too weak.  Even an overgap of .055 is better than an undergap of
.032.  Gapping with a gauge is okay, as long as you know about the
leather compression rule.  Metal stemmed valves are checked at the stem
for travel, not at the poppet face.  The gap is determined at the lowest
pressure able to lift the valve, not at some higher pressure.  That
means, practically no compression -- only enough to make a positive
seal.  So a certain "finesse" is in order, if you are going to be
successful on every valve.

Unless your pressure is constant and unless the leather nap does not
vary, the gaps, after you set them, can vary greatly.  I have seen
meticulous work with a machinist's gauge vary + or - .007 because of
differences in valve compression caused by either the spacers, both of
felt and leather, paper, valve leather thickness and nap variances,
etc.  A home-made feeler gauge is usually better than machine tooling,
because it allows you a close and personal feel of what you're doing,
and you won't trust it altogether.

Usually, in the common vertical valve chest, the finger presses the
valve stem up from its outside seat, while the gauge measures the
travel to the inside seat.  Here too is a potential mistake.  The
finger is very strong and you don't recognize differences between 2
ounces and 2 lbs, often enough.  So while the gauge may be reading
correctly, the finger is changing that reading all over the map (nap?).

Get a piano action jack spring, mount a little button of some kind in
its end to touch the valve stem, and then mount the spring on a little
peg set into a tiny "stool" that sits on the outside seat surface.  Now
each valve will be compressed the same amount.  It's really simple, but
if you really want consistency you have to plan for it.

When setting the lifters to the pouches, the best way to do this,
I have found, is to set 4 or 5 valves from end to end, first, by hand.
Then, in the Standard chest, I will find a straight stick that spans
the chest and slides on its edges, which I then shim up to just touch
the adjustable lifter buttons.  That will give me a pouch clearance of
between 1/16" and 1/8." Putting a gap between button and pouch speeds
the valve's return, which is really the limiting factor of any valve.

The last thing I can advise about doing metal-stemmed valves of this
type is precision of movement.  If the valve guides allow too much slop
around the stems, or if their bushing guides are either damaged, the
felt fallen out, worn out, or crusty with tin residue, they won't work
well.  They will drag the valve and jam it.

The Standard valve is a powerful, fast valve because of the very thin
contact area on its inside valve plate.  If its guides are not
well-centered, or if the stem travel is not straight and true, the
flexibility you put in the poppet connection will not help.  It will
not correct for a stem that can jiggle very much.  It is the precision
of the stem that allows a metal stem valve to work fast and reliably.

Horizontal valves in particular are susceptible to tin crust
accumulation in their guides and wear and tear on the felted holes.
Use a pipe stem cleaner and solvent to remove crust.  And if the felt
has fallen out or is worn, either replace with new bushing felt or buy
all new guides without felt from PPC.  Some guides didn't have felt,
originally.  On those types, I suggest silicone spray for electronics
again.  Coat the stems.  It is a perfectly dry lube, will stay put, and
will protect the tin plated stems from wear.

Craig Brougher


(Message sent Fri 21 May 1999, 13:52:34 GMT, from time zone GMT-0500.)

Key Words in Subject:  Metal, Player, Rebuilding, Stem, Valves

Home    Archives    Calendar    Gallery    Store    Links    Info   


Enter text below to search the MMD Website with Google



CONTACT FORM: Click HERE to write to the editor, or to post a message about Mechanical Musical Instruments to the MMD

Unless otherwise noted, all opinions are those of the individual authors and may not represent those of the editors. Compilation copyright 1995-2019 by Jody Kravitz.

Please read our Republication Policy before copying information from or creating links to this web site.

Click HERE to contact the webmaster regarding problems with the website.

Please support publication of the MMD by donating online

Pay via PayPal

No PayPal account required

                                     
Translate This Page

. .