I suspect that would be used by the piano technician to smooth the felts 
on the piano hammers. AND I believe you've found the answer to John's 
question. They're smoothing irons, used to smooth the felts, which are 
sometimes 'pricked' by the tuner using a 'toning needle' to soften the 
tone. Thanks again to Salaman!

Don

On 2022-07-01 5:03 p.m., Phil Schempf wrote:
> We were all led astray by our typical connotation of a hammer.  There are
> other types of hammers in a piano, as shown here -
>
> https://www.bonanza.com/listings/Piano-Hammer-Head-Smoothing-Iron-Piano-
Voicing-Tool/1271947255?goog_pla=1&gpid=177431040541&keyword=&goog_pla=1&pos=&ad
_type=pla&gclid=Cj0KCQjwtvqVBhCVARIsAFUxcRvZPVtKiJ_oeuOQt4KDhEoNr89fjWvxjPRa9-He
6WXa8OZ4fUM3eskaAqp_EALw_wcB
>
>
> Yikes!  This one should work, too.
>
> Phil
>
> http://tinyurl.com/mr3k43hm
>
> On Fri, Jul 1, 2022 at 2:56 PM  wrote:
>
>> As I recall from watching a tuner, the key wrench was about as long as
>> my forearm, with a solid hand-filling hardwood handle.
>>
>> I remember the tuner using the keys themselves to strike a note.
>>
>> But it's been a long time, Gary Katsanis
>> Albion New York, USA
>>
>>          -----------------------------------------From: "Don Schwartz"
>> To: "John Ruth", "old tools list"
>> Cc:
>> Sent: Friday July 1 2022 6:53:17PM
>> Subject: Re: [oldtools] Are these piano tuner's hammers?
>>
>>   John
>>
>>   I have no doubt Studley would have possessed at least one piano
>> hammer.
>>   Although in his exhaustive book on topic of the Studley chest and
>>   workbench, Don Williams doesn't seem to list one. I did find mention
>> of
>>   a 'piano-regulating' tool, but could not find a photo or description
>> of
>>   it....
>>
>>   Pianos are strung much like guitars and similar instruments, having a
>>   tuning peg which holds tension on the strings. But piano strings
>> require
>>   considerable tension, and so a little thumb button such as you see on
>>   fiddles and guitars would never do. Instead, they are tightened using
>> a
>>   wrench sized to suit the pegs. In my limited experience, they are
>>   generally nice things, plated and brass, with turned hardwood, even
>>   rosewood handles. Salaman refers to it as a tuning hammer, also
>> spinet
>>   hammer and piano wrester. He describes it as
>>
>>   "a small key-wrench with a square, star or oblong hole... used for
>>   turning the wrest pins on which the ends of the piano wires are
>> wound.
>>   The cross handle is sometimes used as a hammer for tapping home the
>>   wrest pins when necessary."
>>
>>   Why they are called a hammer rather than a wrench is beyond me.
>>   Especially since the wooden felt-tipped piano components which strike
>>   the strings to sound them are also called piano hammers.... Autoharps
>>   are tuned with a similar, but smaller wrench. Harps as well.
>>
>>   fwiw
>>   Don
>>
>>   On 2022-07-01 1:05 p.m., John Ruth wrote:
>>   > On Thu, Jun 30, 2022 at 11:30 PM, Don Schwartz wrote:
>>   >
>>   >> They don't remotely resemble any piano tuning hammers I've ever
>> seen.
>>   >>
>>   > Don,
>>   >
>>   > Thanks for that.
>>   >
>>   > Another Porch dweller suggested looking at the Studley Tool Chest
>> to see if anything matches. Henry Studley was indeed a piano builder.
>> Whether a builder ever has need for a tuning hammer is not known to
>> me. In any case, watching a few YouTubes about the famous chest did
>> not reveal anything resembling the tools in question.
>>   >
>>   > So, still wondering about the identity of these mystery tools.
>>   >
>>   > John Ruth
>>   >
>>   >
>>   >
>>   >
>>   >
>>
>>   --
>>
>>   God's away on business - Tom Waits
>>
>>   "...it's just a humpty dumpty world" - Ry Cooder
>>
>>
>>
>>
>>
>> Links:
>> ------
>> [1] https://groups.io/g/oldtools/unsub
>>
>>
>>
>>
>>
>>
>>
>
> 
>
>

-- 

God's away on business - Tom Waits

"...it's just a humpty dumpty world" - Ry Cooder