seeking clarity, was relevance of bridge pin spacing

[Gene Nelson]

> Hi Gene
>
> Thanks. I think I understand what you are saying now.  You use the 
> sideways spaceing to fudge the placement of the bridge pin sets upwards 
> (or downwards) on the long bridge to facilitate your spec'd speaking 
> length. Then you adjust front / back pin distance as needed to avoid any 
> interference between neighboring sets.. yes?

Yes

This is why you raised the
> point about hitch pin placement as well I suppose... because if that isnt 
> a given you get further degrees of freedom I suppose ?
In relation to Ron and Frank using spread sheet - yes. My problem was the 
verticle hitch pins that I installed, (a conversion) their larger than 
original diameter and possible errors in alignment are potential problems 
with unison spacing and string angles.

>
> Two questions also come to mind from the discussion... Ron O mentioned a 
> spread sheet capable of figuring all this out. That of course immediately 
> caused my left temple to itch a bit...  Wouldnt that require the length 
> the center line of the bridge has to the front termination and the overall 
> length of the bridge itself ?  Along with maximum / minimum sideways 
> spacing possibilities I suppose I can see a dim tunnel of light here.
I am not certain if the spread sheet is used for more than varing the bridge 
pin offset. Again, the question of building a new bridge or fixing an 
existing one comes to mind.

Aslo.. how within how many mm does one expect to be
> able to actually conform perfectly to a spec'd speaking length at 
> different parts of the scale ?
I suppose that if a new bridge is part of the work it could be a very close 
tolerence.
On my piano the bridge is in the original position with new cap - by my 
observations of the original cap it appears that I can get the scale 
speaking lengths exact down to note 58 - beyond that the shape of the bridge 
will not allow these adjustments. However, I have no idea if it will all 
work out this way - after I do the initial layout I will find out. My desire 
is not to compromise the speaking lengths.
>
> One other thing... I hear  of three row spacings of 16,  18 mm, 20 mm. 
> The only premade tool I've seen as a punch for this was from Jahn and came 
> at 15 mm. Where do you get these or are they something you just make 
> yourself ?

I am busy trying to make my own from clear plexiglass using Ron Nossman's 
data. I have seen them used in a local rebuilding shop but making them 
accurately is a bit of a task. I get the feeling that making one for each of 
these lengths as well as 3 or 4 bridge pin sizes and several wire diameters 
will be a good investment of my time.
Some of the spacing on the original bridge are 24mm but my intent is not to 
exceed 20mm.

Gene
>
> Cheers
> RicB
>
>
>
>         > Being far from the expert here... I just wanted to throw in a
>        couple
>         > bits.... first is your question leaves me a bit confused as
>        to what you
>         > are actually asking. If you change your front pin positions
>        for reasons
>         > like avoiding interference between neighboring bridge pin
>        sets... how can
>         > you avoid not altering the scale ? Speaking length changes
>        yes... perhaps
>         > this is not what you were saying... ?
>
>
>    My intent is to correct the original scale to as close to my ideal
>    scale as
>    possible. I can accomplish this by altering the original bridge pin
>    spacing
>    to get the fudge room to change the speaking length. I am hopeful
>    that there
>    are no conflicts with front bridge pins as part of this layout work
>    - I will
>    not know about this until I put the plate back in and start looking
>    at how
>    everything fits the new cap. On the original bridge there was quite
>    a bit of
>    variation of speaking lengths and I can correct this from note 58 to
>    88 by
>    changing the original bridge pin spacing. So my priority will be
>    speaking
>    lengths and any variation will be due to conflict with neighboring
>    bridge
>    pins. Any notes lower than 58 will not conform to my ideal scale no
>    matter
>    how I alter bridge pin spacing.
>    Gene
>
>
>