Tuning pin angle(s)

[Farrell]

Hi Jim - I'm by no means the final word on any of this, but I tend to also ponder such things and experiment a bit with all this every time I drill a pinblock it seems. Some thoughts are interspersed below:

Thanks for bringing up this string angle thing - I thought I might have been the only one who spazzed out over things like this!

Terry Farrell
Farrell Piano

----- Original Message ----- 
> In searching the archives and reading whatever info is available
> in past journals etc,  reasonable consensus is that the string takeoff
> angle from the pin centerline to the counterbearing bar should be around
> 90 deg.

That's what happens in my shop. I usually lean the pin back an additional degree or so as I figure there will always be some movement of the pin tipping forward - and then also over time the pin is turned lower into the block, which also will need that extra degree or so to maintain something close to 90 degrees overall.
 
> A couple of questions regarding this:
> 
> 1-in looking at a number of plates, particularly ones with the "ski slope/very 
> minor counterbearing bar/lots of felt contact ", the pin angle in relation to 
> the webbing would have to be a negative angle to achieve 90 deg string takeoff 
> angle from the pin. That is negative, ie  actually angled towards the belly, 
> often by 4-5 deg, assuming coil height at 1/8 " from plate.
> 
> Is 90degrees takeoff ,90 degrees, irrespective of the orientation to the webbing 
> (or actauly the rim top which indexes many rebuilders drilling jig)?

I do not recall ever seeing a piano with this configuration, but yeah, that's what I would do - keep the 90 degree target - otherwise you'll just have your coils stretching out down the pin.
 
> 2-the difference in takeoff angle between the front pin of a unison and the back 
> pin of the same unison results in a very different takeoff angle, maybe 2-4 
> degrees.
> 
> 90 degrees can't actually be 90 degrees throughout, unless you're nuts.

Well, either nuts or it just doesn't bother some folks. I have to admit, it bothers me. Look at the photo below. It is an 1890s Knabe that I put new pinblock inserts in. The top of the pinblock is well below the counterbearing bar closest to the pins and the strings make a definite angle downward to their respective coils. So this is such a case - if coil heights are consistent within a unison, then the strings angle more sharply downward to the pins closest to the belly rail and less sharply to the pins closer to the pianist. 

The angles of the pins in the foreground of the picture are distorted and it actually looks like the  pins closer to the belly rail lean more toward the belly rail - that is not the case. Look at the pins furthest from the camera. You can see that the pins closer to the belly rail lean back more toward the pianist to get something close to the 90 degree target. If I remember correctly, I drilled the two rows closest to the belly rail at one angle, the center two rows are about 2 degrees more vertical and the two rows closest to the pianist are 1.5 degrees more vertical than the center rows. 

This approach successfully maintained the 90 degree target pin/string relationship when keeping coil height consistent. Another approach would be to drill all tuning pin holes at the same angle, but simply make coil heights higher (tuning pin height higher) on the pins closer to the belly rail. I just like the idea of reducing any tendency of pins to flagpole - so I like to keep the coils down close to the block - on this particular piano I am using 1/0 pins.

Doing it this way also causes the strings from the pianist tuning pin row to ride up higher than the strings on the belly rail row - the pianist strings may even be slightly higher than the top of the coils on the belly rail row. I tested the fit of my 1/0 tuning pin socket on my tuning lever and found that it stays up quite high on the pin, so that won't cause any trouble at all. If you try to turn these 1/0 tuning pins with a 2/0 socket, you will find that, whereas it can be done, the overlapping strings will cause interference problems on the pins closer to the belly rail. Just use the proper tuning pin socket and there is no trouble.




> 3-the 90 degrees(or so) is not in relation to the stretcher, but in relation to 
> location of the agraffe, which again changes from note to note. Does anybody 
> actually customize the direction of the angle from note to note?

Yes. Just measure and angle your drill. My new digital angle gauge make this a very easy, quick and accurate task.

> 4-Regarding the "ski slope/very minor counterbearing bar/lots of felt 
> condition"...rendering the string over all this felt creates problems because of 
> the tendency of the wool to hold 
> moisture, and rust the string/felt contact. 
> 
> ??Why is wool felt exclusively used in this place?  Besides the obvious reason 
> which is "because that's the way its always been done".  Some rebuilders do 
> infact use acrylic felt here, but keep it quiet in the fear that they might be 
> struck by lightening if anybody knew their dirty secret.  Any thoughts?

I haven't had the pleasure of restringing a piano with this type of counterbearing setup - however, I have certainly tuned (or tried to) a number of pianos like that - Baldwin grands (M, R, L) come to mind. Yours are interesting questions. What about modifying the ski slope by adding two counterbearing bars at either end of the slope? The strings would ride over the two bars, but the bars would be just tall enough to keep the strings off the moguls in between the two bars. Kinda like the picture above - a counterbearing bar just as the strings come out of the capo or agraffes and then a second bar just before the tuning pins. Or even three bars if two would have to be too tall (creating string angles that are too sharp). You could even place some felt between the bearing bars to hush unwanted noises - but make the felt just tall enough to quiet the strings - not to tall that significant friction occurs between the felt and string.

If (when) I do one of these types of pianos, I can guarantee I will not use the original configuration.

> Jim I   
>
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