[pianotech] brass rail duplication

Encore Pianos encorepianos at metrocast.net
Wed Sep 12 03:20:37 MDT 2012


My hope is to get the piano to work satisfactorily, ideally with proper new parts.  Lacking that, moving the rails so that they will work.  

 

As for payment, I have his deposit for the parts which was paid to the supplier.  Whether or not the piano is worth it, it is not his fault that the supplier does this poor quality of work, nor is it mine.  I see no sense in fighting with my customer about payment before I know where we are with this thing.  

 

Will 

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of tnrwim at aol.com
Sent: Tuesday, September 11, 2012 10:31 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] brass rail duplication

 

This piano, however was a Craigs List special that he had moved from MA. To New Hampshire.  I did advise him against doing what I am doing given the overall age and condition of the piano. But he insisted on the repair.  

So is he going to pay you for all the work you've done, much less the cost of the brass rail, even though the piano won't work?

 

Wim

 

-----Original Message-----
From: Encore Pianos <encorepianos at metrocast.net>
To: pianotech <pianotech at ptg.org>
Sent: Tue, Sep 11, 2012 4:26 pm
Subject: Re: [pianotech] brass rail duplication

Fair enough, Wim, and something I do regularly.  This piano, however was a Craigs List special that he had moved from MA. To New Hampshire.  I did advise him against doing what I am doing given the overall age and condition of the piano. But he insisted on the repair.  

 

So here I sit with a broken heart, I took 2 bennies and my semi-truck won’t start (Commander Cody and the Lost Planet Airmen)

 

Will

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org <mailto:pianotech-bounces at ptg.org?> ] On Behalf Of tnrwim at aol.com
Sent: Tuesday, September 11, 2012 10:08 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] brass rail duplication

 

Maybe the jig used to make the new rails is bad, or the materials used is not what it used to be, or the guy who is doing the work isn't experienced enough to do the job right in the first place. But for whatever reason, maybe we should all learn the lesson that brass rail replacements are no longer available.  

So my solution, and I'll probably get a lot of flack for saying this, is to tell the customer that replacement parts for brass rails are no longer available, and it's time to get another piano. If the problem had been a rotted out pin block, or badly split bridge, or completely worn out action, what would you tell the customer?  As long as they work, old uprights are great. But there come a time when we need to say, "enough is enough, it's time to bury the sucker".

 

Just my 2 cents worth

 

Wim 

-----Original Message-----
From: Encore Pianos <encorepianos at metrocast.net>
To: pianotech <pianotech at ptg.org>
Sent: Tue, Sep 11, 2012 3:05 pm
Subject: [pianotech] brass rail duplication



To the list:

 

A few weeks ago I sent two brass rails from a big old Henry F. Miller upright to a supplier (who shall remain unnamed) for duplication.  After several weeks I got them and put them back on the wooden action rails, mounted the original parts onto them with the brass rail butt plates, put everything together and went to my customer’s house to put it back in and go from there.  

 

The first thing that jumped out at me was the fact that the hammer shanks were sitting a good 1/4” off the hammer rest rail.  Moreover, a number of notes were now blocking against the string because the let off had changed also.  It was interesting to note that a number of hammers were wedging lightly against the wooden top of the damper head because there was no longer sufficient clearance.  

 

Allow me to establish a fixed point before you put your thinking caps on:

 

The bottom of the original brass rail was resting on the shelf of the action rail when screwed into place.

 

The replacement rail, when screwed into place, was also resting on the shelf of the action rail in the same place as the original. 

 

So screwing the rails into place did not change that particular relationship, and allows me to use that as a point of departure because it is the surest point of reference since it has not changed from one rail to the other.  

 

I took several measurements with my digital .001 caliper before getting back to the supplier with my findings.  They were:

 

		
New 

		New 

		


Hasenjaegar Miller upright 

Old 

treble 

Difference

	tenor 

Difference

	
	

Rail

Rail 

 

	Rail 

 

	


Measure bottom of bracket to center pin v

0.886

0.851

0.035

smaller

0.854

0.032

smaller


Center of screw hole to center pin V

0.671

0.650

0.021

smaller

0.640

0.031

smaller


bottom of bracket to top of individual mount 

1.032

0.999

0.033

smaller

1.000

0.032

smaller


bottom of bracket to top of brass plate pin 

0.547

0.528

0.019

smaller

0.535

0.012

smaller

 

 

I took measurements at 3 points on each rail, they were pretty consistent, variations no more than .001 to .002, the above figures are the average.  My relatively new caliper is certified to within .0005.  When I compare my readings against a micrometer, variations of .001 or less.  So my caliper is sufficiently accurate and consistent.  

 

The center pin V is the slot that holds the butt center pin to mount it to the rail with the butt plate. You can see that that distance is .035 smaller on the treble rail, and .032 smaller on the tenor rail 

 

The center of screw hole to center pin v is .021 on treble rail, .031 on the tenor rail.  This measure is compromised by the fact that I was eyeballing the center of the hole, but both are smaller than the originals

 

The following measurements are not critical, but instructive nonetheless.  

 

The bottom of the bracket to the top of the individual mounting arm is about .033 shorter on the new rail. As long as this arm is not too long or too short, this measure is not critical

 

The bottom of the bracket to the top of the brass plate guide pin is .019 smaller on one, .012 smaller on the other.  This is not critical either, so long as the butt plate is able to full cover the center pin.

 

 

As you can see, everything is smaller.  As best I can judge, the most accurate and meaningful measure is the first, the bottom of the bracket to the center pin v.  Since the bottom of the bracket is sitting on the shelf with both rails, this can only mean that, in reference to everything else in the action, the center pin v is .035 lower than on the original rail.  This means that any part of the butt and the hammer is now sitting .035 inch lower.  

 

The butt leather is now .035 closer to the jack top, because that position has not changed.  Presumably that is why the hammer shanks are sitting ¼” off the rail now.  The reason why the hammer bottoms are now touching the top of the damper heads.  And, of course, the geometry regarding the intersection of arcs between the butt leather profile and the arc of the jack has changed, and not for the better.

 

I spoke with the fellow who made it at the supply house.  I asked him if he had a caliper or other means of measuring needed values to assure accuracy.  He told me that he did not, said that he eyeballed it when it was done, and he thought it was good enough.  Apparently they have an indexing system on their milling machine that allows them to duplicate rails without using measurements.  The essence of it is that he has no reliably accurate means of checking his work or whether or not the machine has drifted or worn its way out of tolerance.  

 

I sent the rails back to be done again, asking that they buy a caliper and check their work. Their technician, not the same fellow, called me to tell me that the he had measured the distances I had given on the new parts with his caliper accurate to .001.  He said both the first and second sets of rails came out essentially the same, and varied from the original by 3 or 4 thousandths.  So he thought my caliper was suspect.

 

We argued about who was right for a while.  He thought it was sufficiently accurate, they had been doing this for 50 years, and they had never had any problems before. He told me I should be able to make it work and besides, what other choice do I have, since nobody else makes them?  

 

 

Finally, the 64,000 dollar question:  Would any of my dear readers find a tolerance of .035 acceptable, or is that value totally out to lunch?  If you were in my shoes, where would you be finding yourself sitting?

 

Thanks for your help.

 

Will Truitt

 

 

 

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