[CAUT] jack alignment

[Mark Cramer]

I tend to think of the jack position screw like the "fine-tuner" on a
violin. For others, the drop screw is the "fine tuner."

IOW, when all four adjustments are as close as I'm able, I will use the
sychronization of let-off/drop contact, (what some refer to as
"single-contact escapement") as a "fine-tuning device" for optimal jack
position.

Like Jim, I find it easy to be precise with let-off, drop and rep height,
but jack position can be tricky... ( I tend to end up with "drop-screw
shaped indents" on whichever side of my head's been resting on the hammer
rail! :>)

So, although I try to be precise, I don't anguish too much over this
adjustment, knowing the "fine-tuning" stage will dial it in precisely where
it needs to be.

Going back a step or too, it's a great idea to pre-regulate a test note and
prove dimensions beforehand:

i.e.: If a particular action is needing a smidge more rep height, or a
little wider drop than typical, I will explore the other 3 adjustments to
see where I can offset the compromise. On at least one occasion, this has
even meant setting the jack slightly behind the knuckle core, but with
absolutely no detriment to the touch.

("fine regulation" always presumes knuckles to be in optimum condition)

At the other end of things, jack-position as the "fine-tuner" is a great
diagnostic tool:

i.e.: After fine-adjusting, if I notice a jack out-of-line, I can lift the
shanks and see if the knuckle is also out of line with it's neighbors, or
perhaps the jack is telling me I've left the repetition lever a bit too
high, etc. When I correct the rep lever height, I will fine-tune the jack
position again, and expect it will line up nicely with it's neighbors.

IOW, even though I'm "re-negotiating" jack position without reference to the
knuckle core, I fully expect the jacks to end up in a nice straight line,
and positioned exactly where they're supposed to be, relative to the
knuckle.

Most times there's no adjustment needed at all.

So my recommendation is to use whatever bulk method you prefer...  a
string-line, sighting down the neighboring knuckle, etc. to get the jacks
"close" in a hurry.

Then, do the fine adjustment of jack position (black, white, otherwise)
comfortably from the back of the action, with shanks up, using the initial
motion of the jack-top (post drop-screw contact) as your precision
reference.

best regards,
Mark Cramer,
Brandon University




  -----Original Message-----
  From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org]On Behalf Of Chris
Solliday
  Sent: Wednesday, August 08, 2007 9:29 AM
  To: caut at ptg.org
  Subject: [CAUT] jack alignment


  I, like Fred Sturm, have found that many of my clients prefer the more
positive feel of the jack further under. I certainly never have cheating
problems when adjusting that way unless there are flange problems. I might
be tempted to try and eek out a little more speed of repetition if someone
complained about it being slow but then there are so many other issues
available I would rather address them first. So I'm saying being on the edge
of cheating may not be the best position even for a concert regulation. I
usually do as Fred with a taut thread line after setting end samples, then I
check individually for anomalies. That yields a more consistent result than
trying to do 88 individually, at least for me with my eyes and usual
concentration level. I do like the "Garlick method" offered by Michael for a
"quickie" though.
  Paul is right, we get such good food for thought at this trough. Lucky us.
  Chris Solliday
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