Tuning Pin Height by Danair

[Farrell]

"A picture is worth a thousand words."

Any chance of you sending one directly to me? I know some folks get bogged
down with pictures - I don't.

You gave a very detailed account of your system - please don't fret if I
still don't quite understand. Your old system is essentially what I have
used. Let me see if I have a correct understanding of your new approach: You
take an appropriate length of hammer shank and hose-clamp it to the outside
sliding/retractable sleeve of the nailer at the proper position such that as
you are pounding the tuning pin in, the hammer shank will touch the plate
BEFORE the tuning pin is driven in to its desired depth - but you continue
driving it in - now the hammer shank is pushing the sliding sleeve to a
retracted position - and continue driving until the hammer shank pushes the
sliding/retracting sleeve back far enough to the point where it holds back
the driver piston from being activated because it is no longer exerting
pressure down on the tuning pin top. (Wow, was that a mouthful or what?)
Assuming your hammer shank is the right length and was positioned correctly,
your tuning pin is now exactly at the desired height - as are all of them.

If I am right with the above, doesn't the hammer shank end mark the plate?
Or does the sleeve retract so very easily that it doesn't mark the plate? I
guess if one was worried about it, you could cover the contact point with a
piece of leather or some such.

Thanks for your explanation. I hope I have it right! I would love a picture
if you have one. Thanks

Terry Farrell

----- Original Message -----
From: "Bill Ballard" <yardbird@pop.vermontel.net>
To: <pianotech@ptg.org>
Sent: Sunday, October 28, 2001 1:03 AM
Subject: Re: Tuning Pin Height by Danair


> At 4:10 PM -0400 10/27/01, Farrell wrote:
> >Hi Bill. I was one of those who posted on this wonderful tool. I find
your
> >method of getting consistent pin height intriguing. It sounds as though
you
> >are attaching some device that physically stops the nailer from pounding
> >further than the desired depth.
>
> Absolutely. You should start with my trust and now retired system, a
> 6" pin punch (Schaff 174A) with a vertical hammershank held on by two
> small hose clamps (A machinist welded be a small blob for me, into
> which I carved a small square ledge to back up the top end of the
> shank/dowel gage stick.) With the depth gage of a dial caliper, I
> laid out the desired TP height on the shank and trimmed. Then as I
> pounded the pin in and the depth gage closer to contact, I would lean
> it backwards a few degrees while driving, and swing it down into
> parallel when checking. Yes, I have seen the tell-tale marks of this
> system on plate finishes of the '70s studio uprights, but there rods
> were probably steel (or they were in a bigger hurry).
>
> >I have attached a thingee to my nailer and
> >visually observed that the nailer was at the desired height. Your method
> >sounds more definitive.
>
> There was plenty of room for first-time fudginess, but for under ten
> minutes, it sure looked good to me.
>
> >Can you please describe exactly where and how you
> >attach exactly what to your nailer to get it to stop at height X? Got a
> >picture?
>
> Let's see, I can switch Eudora to HTML mode and paste a picture in
> the body of this email. Y'all got reasonable machines, right?
>
> The nailer drives until the piston rod is now longer activated. That
> happens when the nailer body is prevented from moving any closer
> towards the surface (presumably because the 16p nail is driven flush
> and the fat sleeve assembly surrounding the rod has made contact with
> the surface). The sleeve assembly consists of a ~1.5" dia. plug (I'm
> sorry I don't have the parts diagram here in the office), which
> thread into the housing of the nailer. This plug is ~1" tall, and
> inside it telescopes a steel sleeve pushed from behind by a spring to
> the sleeve's furthest extension. As the nailer approaches the surface
> first this sleeve will contact is and then be pushed into retraction.
> At the sleeve's utmost retraction the piston rod no longer has the
> initial retraction it requires to trigger, and the driving stops.
>
> All that is required for the length of the height gage is the desired
> pin height (possibly not a standard for you, from piano to piano),
> and the displacement of the rod which falls just short of triggering.
> The first comes from the piano.
>
> The displacement required to trigger, I derived from two adjacent
> transfer punches (you could use adjacent drill bits). The sliding
> sleeve was removed from the plug, which is the fixed object in this
> assembly anyway. Using the roughly equal punch rods to set the nailer
> down on, the end of the piston rod (at rest, always a fixed distance
> out from the plug) will either be close enough to trigger or
> out-of-range and unemployed. I simply moved up in punch rod diameters
> until they held the rod high enough off the surface that although it
> may have depressed the rod but not enough to trigger the valve.
> Again, my notes are at the shop, but it seemed around .220".
>
> TPHeight + (just under)TriggerDisplacement = gage length
>
> This gibes me the length to which the hammershank is trimmed. I then
> put the sliding sleeve back into the plug and reinstall the sleeve
> assembly, extend the sliding sleeve to its fullest (actually it could
> be anywhere--we're not indexing off it but off the plug rim--but we
> are using its length to lash the gage stick against). When the gage
> is fastened to the sleeve with is top end just even with the plug
> rim, the bottom of the gage will approach the surface of the plate,
> and as soon as that distance equals zero, the piston rod will be
> prevented from retracting the amount which it needs to trigger. The
> beauty of this system is that, unlike my old system where the the rod
> was slaved to the punch and could yet pounded into the plate as the
> tuning pin was driven, here the contact between the plate and the
> gage results directly in the nailer being prevented from driving.
>
> The 3/4 hour R&D time(including going to the hardware store for wider
> hose clamps) was well worth it. A picture is worth a thousand words.
>
> Bill Ballard RPT
> NH Chapter, P.T.G.
>
> "Schumann wrote in spurts, composing an incredible amount, then
> writing nothing for a stretch. While Clara was away from home giving
> concerts, Schumann was completely unable to compose."
>      ...........A "Junior Scholastic" profile of Robert Schumann.
> (Say, if Robert was unable to get any composing done when he was on
> kid duty, how come his wife had no problem preparing her programs
> while looking after the six kids in that household?)
> +++++++++++++++++++++
>