Steinway Action Nut

[Dave Nereson]

----- Original Message ----- 
From: "Paul Chick (Earthlink)" <tune4@earthlink.net>
To: <mortier@netreach.net>; "Pianotech" <pianotech@ptg.org>
Sent: Wednesday, February 04, 2004 9:37 PM
Subject: RE: Steinway Action Nut

> Anyone have a Steinway upright action nut to spare? I have a
> 1912 model missing one. My machinist wants $90 to make it!
> It's a simple, concave brass nut with 1/4" X 27 thread.
>
> Philip Jamison
>
> Phil
> I may have what you are looking for: Brass, concave 1/4x27 thread, .500"
> tall, .980" large diameter with knurled edge, .690" base diameter machined
> square to contact surface.  You may contact me off the list if you need
it.
> Paul Chick Sr
pianotech list info: https://www.moypiano.com/resources/#archives


    One of my customers has an 1880 Steinway upright (#44008) that has
similar action nuts.  These are 3/8" tall, tapered from 5/8" to 9/16", with
vertical grooves all around the outside (not really what is known as
knurling nowadays) spaced about 1/16" apart.   The action bolt measured
.217"   (7/32" is .218").   And yes the threads are 27 t.p.i.   I measured
with a pitch gauge.  I was planning to make one from 5/8" brass rod, a short
piece -- chuck it in the drill press, put a taper on it with a curved-tooth
file (meant for soft metals), then make the grooves with a little cutter in
a Dremel tool, saw it off, then drill a hole in the middle and tap it with a
12-28 tap, which I hope will be close enough.
    He's willing to pay for an exact copy so I was going to see if you could
have two made, but it sounds like the one you need is bigger (1 inch
diameter, concave --  I think I've seen these also).  If anyone has one with
those smaller dimensions, I'm willing to buy.
    Surely by 1880, most machine screw sizes were somewhat standardized.
How did they come up with that 27 threads/inch?  Of course many other things
in pianos became standardized except with Steinway, namely capstan screw
sizes, flange shapes, and sostenuto mechanisms.
    --David Nereson, RPT