[pianotech] Wegman, we have a problem

[Patrick C. Poulson]

John: thanks for the information. I will try these techniques, and hopefully 
one will be the cure. BTW, when you used new pins, did you have to cut them 
to a shorter length, and if so, how did you cut them?
Thanks,
Patrick C. Poulson
Registered Piano Technician
530-265-1983
----- Original Message ----- 
From: "John Delacour" <JD at Pianomaker.co.uk>
To: <pianotech at ptg.org>
Sent: Thursday, September 02, 2010 2:42 PM
Subject: Re: [pianotech] Wegman, we have a problem


> At 12:24 -0700 02/09/2010, Patrick C. Poulson wrote:
>
>>I am restringing the Wegman upright that I spoke about in an earlier 
>>email. The problem is that I am finding that some of the tuning pins no 
>>longer have enough friction to hold to pitch. The piano uses .284 diameter 
>>1 1/2" unthreaded pins that go in to a slighter oval hole in the plate 
>>(there is no pinblock), and create sufficient friction by the pressure 
>>against the narrow end of the oval hole. Usually, that is. Many pins in 
>>the tenor and bass sections slip. These are the options that I can think 
>>of this point:
>>1. Use epoxy or CA to tighten the hole, as in a wooden pinblock.
>>2. Use a shortened standard, i.e. threaded,  3/0 tuning pin . This would 
>>require cutting or grinding a number of these down to the correct length.
>
> Hello Patrick,
>
> You will remember from the previous thread that I mentioned the Papps 
> upright made in England the has a similar but not identical system. I 
> posted a description and a picture.
>
> I now have two of these -- a vertical and an overstrung -- and have been 
> experimenting with them.  I got the vertical simply to investigate the 
> system but I intend to rebuild the overstrung because it has great 
> potential.
>
> First of all I'd say DON'T PANIC!  It's simply a question of friction and 
> can easily be solved, I'm sure.  With the Papps I have had no problem 
> whatever pins I use -- threaded, not threaded, oversize, undersize, same 
> size -- though the cleaner things are the smoother the feel in tuning.  I 
> got the 1924 overstrung on eBay a few weeks ago and it arrived at pitch 
> and pretty well in tune, and there it has stayed.
>
> The vertical has smooth pins and the overstrung has file-roughed pins.  It 
> seems to make very little difference and simple laws of physics dictate 
> that the friction will be the same in either case.
>
> My guess is that you simply need to make sure that the sides of the hole 
> are clean and that the pin is clean.  You could also roughen the pin with 
> a file to speed up the process of settling in.  But I think that if you 
> pull the string up to a few semitones below pitch, then up and down a bit, 
> applying a slight downward pressure on the pin all the time, you will find 
> that it holds and will continue to hold.
>
> Using CA glue would almost certainly be worse than useless because you 
> would reduce the coefficient of friction and give yourself a lot of work 
> cleaning it off.
>
> You can (at least on the Papps) use a larger or a smaller pin to bite at a 
> slightly higher or lower point in the tapering hole.  If the sides of the 
> hole in the cast iron have been eroded by the wear of the previous pins, 
> in other words the sides are not giving a straight taper, then you must 
> use a larger or a smaller pin because the whole system relies on a certain 
> angle of taper.  I have not come across this problem on the Papps, since 
> if anything wears it is the pin and not the hole, but in theory it is 
> possible.
>
> In any case I am sure you will find you had nothing to worry about.
>
> JD