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Hi,

I have a 1983 Baldwin Model L grand (6'3") that will undergo some rebuilding in February. The work will include installation of Arledge Bass Strings, Mapes IG wire for steel strings, and Ronsen Wurzen hammers and flanges. I live in Bangor, Maine where there are not a lot of Baldwin's around.

My question is this: As I look at the Acu-Just hitch pins, depending on whether I look at the bass, tenor or treble, in some places the wire is wrapped around the hitch pin half way up, in other places about a third the way up, and in others, two thirds the way up. Should all the strings be hitched at the exact same height, or are there specifications on the height at various scale points that are published somewhere?

I'm the owner, not the technician, but just want to be sure that the work is done exactly right, as it appears to me that it will affect the downbearing. This system is more complicated, it seems, than on the Steinway, where you slip the wire around the hitching hook and it's done. Any advice you have on this would be greatly appreciated. Thanks!

David

Baldwin adjusts the Accu-Just hitch pins according to percent of string tension.

They have a special gauge for it.

Longer back scale strings will be lower on the Accu-Just hitch pin in order to have the same bearing load on the bridge as shorter back scale strings.

We just had Tom Malone from Baldwin here for our November meeting.

Tom gave a very good explanation of how they set the accu-hitch pins.

There are indeed specs for setting bearing in Baldwin grands that use the accu-just hitch pin arrangement.
From their service manual www.tinypic.com/42iaoub.jpg

Thanks, Larry and Curry for your explanations.

As I read the service manual excerpt, the precision required seems daunting. And it appears that where there is even variance in tolerances between instruments of the same model, it's a bit of art as well as science. Although my tech has taken care of my Baldwin for 13 years and rebuilds pianos, he has never tackled restringing a Baldwin with the Acu-Just system.

So, if he writes the factory for instructions and a Baldwin guage (as the excerpt suggests), is it likely a tech not factory trained can successfully do this task using just those instructions and the guage? Or will it be necessary to have an experienced factory tech travel here for the restringing? Worse yet, will I have to ship the piano back to Baldwin in your opinion? And if it comes to that last option, will they be likely to respect my wishes to use the Arledge Bass strings and Mapes IG wire, or would they insist on their Syncratone II strings and their Renner hammers rather than the Ronsens I want? Complications!

Most importantly and obviously, I don't want to risk plate and soundboard damage if the task is not done absolutely correctly! I'm feeling in a quandry now. Any other guidance you can give will be most helpful. Thanks again.

David

I recommend you ask him how he measured bearing.

If he has rebuilt many piano's, at worst he is in the right ball park.

Baldwins system allows for greater accuracy note to note in down bearing given the unequal lengths of the back scale.

I think it's likely your tech is reasonably close.
Rebuilding pianos gives him a pretty good feel.

I would not be concerned about damage just because it is a Baldwin.

I have not tried to acquire a "factory gauge"
They are specially calibrated for each note.
I don't know how readily available they are.

If your tech has a Lowell downbearing gauge, then the easiest way to do a restringing job is to measure and record the back scale deflection measurements of the strings on every hitch pin, and then set all the new strings to the recorded measurement.
You need to do it the same way they string at the factory. They first center the loops of every string on each hitch pin with very little tension on the strings. Next the piano is chipped up to pitch starting with the bass and high treble, follwed by the tenor. After the piano is chipped up to pitch, the correct bearing measurement for each piano is set using a special bearing gauge to determine the correct amount of bearing for each section of the scale by raising up or tapping down the strings on their respective hitch pins.

Curry and Larry,

Thanks again. After reading your subsequent messages, I'm feeling better already. I'll send them along to my tech to see how he feels about it. I really appreciate it!

David

The Baldwin accujust pin rises 1/2 inch above the plate and the factory spec for max height of the string is .375" above the plate. Much higher could bend the pin.
Factory specs for bearing is less than other similar pianos and the spec for the L model is stated as % of the string tension and it changes across the piano - 0.5% in the bass and up to note 40, 1% to note 53 and 1.5% to the top.
Factory spec is very specific about stringing the piano and setting bearing - the problem that I have with the technique is that after the initial setting the piano is left to adjust to whatever bearing is set and does not allow to measure the resulting bearing and readjust string hight for any changes. The bearing specs are initial, not final. (string, chip to pitch, set bearing and leave it alone)
Kind of a waste of an accujust pin.

Hi scutch,

Thanks for adding some additional facts and thoughts about Acu-Just. It gives another angle on the "how" of it all.

A former Baldwin supervisor told me the gauge is used for one pass only. He said resist the urge to do multiple passes to double check your work.

I have heard the same line and do not buy it.
This may work for a new piano at the factory where they are aware of the support capacity of the soundboard/rib assembly. (Even then I think it a mistake to resist the urge to check your work) What about a 25 year old piano?
I do not think that it is possible to predict what will happen to a board after string tension is applied - unless it is flat to begin with.

I think Scutch is right. One pass is good enough for gov't work, excuse me, factory new piano work. For an older piano, or to get the best performance out of a new one which has got a perceptive owner and technician, there are further possibilities.

At the factory level, They have developed a process that an employee is trained to duplicate.

That same employee is not trained to tune the piano and evaluate the sound. The first pass is designed to accomplish that task to a certain point designated by the design team.

The production environment that manufacturers create is very different than the environment in a rebuilders shop. Rightly so.

Personally, I would not underestimate the manufacturers ability to evaluate what they are doing and adjust.

Certainly, there are also many rebuilders that also define high standards as well.

I am still looking for a mid 60's Baldwin L plate as well.....

As I shop for a good older Baldwin L, what were the years that the pianos used the Accu-Just pin system?

Is there consensus out there as to whether that system is better or worse than a solid hitch pin?

Phil

RachFan, I was a Baldwin piano dealer for 7 years and have been a piano rebuilder for almost 40 years. Too many of the grands arrived with tonal deficiencies that could be traced to deficiencies or excesses of downbearing. As such, I increased or decreased downbearing as needed, to audible improvement. It is a system that can be finessed if one has the understanding and inclination to do so. In the right hands, it is a very accurate and precise way to set bearing. I like the power that it puts into my hands to individualize the bearing for each note.

The factory recommendations for the height off the plate do not represent the real world of bearing in a Baldwin grand. I have seen them much higher than .375 on many occasions. If one is setting the bearing correctly, the wire may end up much higher on the pin due to plate warpage. I have seen them near the top without breakage. So it is a matter of what the piano will allow you to do, even as you want to respect the recommended maximum.

I have not had occasion to restring a Baldwin with accu-just hitch pins. Setting bearing in an old board must consider the amount of residual crown, so the factory specs might need to be modified somewhat. The only way you will know is to take crown and bearing readings before teardown.

I have digital copies of 4 different manuals for the hitch pins and the perimeter bolts which I will happily share with you. I am Will Truitt of Encore Pianos in Franklin, New Hampshire. My e-mail is encorepianos@metrocast.net Contact me privately and I will forward all of them to you. What I have will be very complete.

It was a clever design, being able to adjust bearing as one needs throughout the life of the instrument (well the life of the board and bridges really).