Need explanation of terms

[Dave Nereson]

----- Original Message -----
From: Gordon Holley <gholley@hi-techhousing.com>
To: <pianotech@ptg.org>
Sent: Monday, July 16, 2001 12:02 PM
Subject: Need explanation of terms


> Hello List.  Over the past months, while reading the posts and exchanges
on
> the list, I've encountered three terms used in the authors dialog.  I've
> read through two books 1) Piano Servicing Tuning & Rebuilding, by Arthur
> Reblitz, and The Technical Examination, Source Book - PTG, and cannot find
> any explanation on the three terms.  Will somebody assist in my search:
> 1. "Burning In" - used in the explanation of hammers and the shank area.
> 2.  "Get The String To Render" - I know what render means, but what does
> the term render mead in this usage?
> 3.  "Raking The Hammers" . - Sure don't understand this one.
> Thanks in advance for the help.
> Gordon Holley
> Goshen, IN
> gholley@hi-techhousing.com

    "Burning in" refers to a method of correcting hammer angle (hammers that
aren't perpendicular to the string).  Look for hammers that aren't parallel
to their neighbors, then heat the shank with a heat gun for about 15 - 20
seconds, an inch or two away from the shank, and  preferably with a curved
guard that fits on the nozzle so you don't burn nearby felt, then remove the
heat and quickly twist the hammer in the direction you want it to go, but go
just a little too far, since it will spring back slightly. Just takes
practice and experience.  Don't hold the heat on so long that the wood
scorches.  And in uprights, if you're straightening many hammers, you might
tip the action back so you don't heat the strings up, making them go flat.
    "Render", as I understand it, is just getting the strings to pull
through their various friction points (aliquots, bridge pins, pressure bar,
capo bar, agraffe, etc.) so that the tension in the speaking and
non-speaking segments of the string are equalized.  I've never been able to
actually feel in the tuning hammer that the strings are pulling through the

bridge pins (it's only a few thousandths of an inch, if that) -- I just back
them down ever so slightly, then overpull in a quick almost-jerk, trying
(hoping) to get the whole length of the tuning pin to rotate -- not just the
top, then settle it back down to where I want it, all in one motion, sort
of -- it happens in about a third of a second.
    The "rake" in a set of hammers is the difference between their angle to
the shank and a right angle.  Theoretically, hammers should be hung at 90
degrees to the shank, but in many verticals, they're at more like 88 (a
"rake" of 2 degrees) or even 85 degrees (a 5 degree rake), supposedly to
compensate for the flexing of the shank upon impact.  --Dave Nereson, RPT