Short Tips, Long Post

[Tom Cole]

I just finished reading the letter in PTJ entitled "Bending Pins" and I
am moved to comment. I hope that the author, Jack Brusette-Mills, is on
the list but, if not, all are certainly welcome to respond. It takes 3
months for a letter to get published in the Journal and, this list being
so much more immediate, I thought that a change of venue would be
appropriate.

The main point of Jack's letter is that when you tune a piano, you are
bound to bend the pin, that this is not a great sin and that, by how you
position the tuning lever, you can control the direction of the bending
such that you don't needlessly change the pitch so much in the course of
settling the pin. No argument so far.

Another, auxilliary point is that longer tips bend pins more than
shorter ones and that the shortest tip possible should be used. This is
where the author and I part company. This is also where I will probably
draw some fire because it is a restating of a common myth that is
repeated by so many in this organization. 

Jack said that he "would like to end the debate on 'bending tuning
pins'" but I think that some very scientific experiments need to be done
before we can pry any pet ideas away from their masters. And even then
we can expect some Cling-ons to remain (Mr. Sulu, activate deflector
shields!).

Performing a vectoral analysis will show that the length of the tip is
only one factor in the equation and that the angle of the head must also
be considered. If the tuning lever is high enough to clear the plate
struts, it matters not if the tip is long and the head angle is low, or
if the tip is short and the head angle is high. You still end up with
the end of the lever in the same height above the plate and the tuning
pin has no eyes to see that you are tuning with a lever of one style or
the other. It just knows that when you push or pull at a given height, a
certain percentage of that force registers as a pin-bending force
because you are not exerting that force at the level of the tuning pin.

To get a virtual feel for what I'm saying, imagine that you are tuning a
grand piano and that, on a tuning pin, you have a twelve-inch-long tip
with a handle attached to it that puts the handle, pointing at you, at
the level of the pin block. This means that there is a twelve-inch
downward offset in the shaft of the tuning wrench, to compensate for the
long tip, which allows you to turn the pin in the block with no
unintentional bending. It's just as if you had removed the stretcher and
were turning the pin with a flat ring spanner (box wrench).

Imagine now that you are changing to a tuning hammer that has a short
tip and a 45° head. Half of your exertion is turning the pin while the
other half is bending the pin.

In this extreme example, the long tip works better than the short one,
if you discount for the kluge of a handle you need for the long tip.

IMPO, the reason that the short tip was invented was to allow the tuning
of pins which are located in tight spots (player action or case parts in
the way). Understand that I'm fine if the rest of PTG uses short tips on
everything. But Jack is asking for agreement amongst us that the use of
short tips minimizes pin bending (with no mention of head angle). If
someone can provide plausible arguments in support of this thesis, I'd
be happy to consider them. Or any comments you might have, yea or nay.

(For the record, my personal preference is to use a long tip and a
Coleman 20° head for all grand piano tunings, regular tip and 15° head
for uprights, short tip when necessary for players. I like the looks of
the regular tip with stainless steel head, made by Keith Bowman, but I
prefer the clearance the grand piano rig gives me and I've learned to
control the pin-bending consequences.)

Tom

-- 
Thomas A. Cole RPT
Santa Cruz, CA