Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Reconditioning 1923 Gulbransen Player, Replacing a Bridge

I had a feeling the cart was going before the horse. A car mechanic friend likes to say, "Ya don't rotate tires by first taking out the transmission." As Gene said, provided the bridge placement doesn't vary you can get close. I like to use heavy brown packing paper and use sandpaper for the impressions. I feel it is more accurate than pencil rubbings. If you try to get termination impressions without the strings in place its important to keep that paper taught. Too much slack will throw of the winding placement and there could be problems getting it to pitch.

Dan do you have all the proper tools for tuning and restringing?

Why do you capture the tuning pins ?

the length of winding I leave to my winder to choice. If memory serves it is suppose to be 25 mm and 28 mm after 3 tunings.
They work from distances A & B mostly an provide always a very nice lining of the wouned portions.

They also ALWAYS have a look at the parameters of the strings, an use a TF65/ slide rule when in front ogf the winding machine, to determine how are the progressions (computers would take too much time) . SOfter wire in the first basses , generally better on smaller pianos. (not the case there)

the bridge APron have 2 roles : indcuce some suppleness for the strings to be allowed to move enough (strong attack)

Install the transmission of the vibrations in a more supple part- of the soundboard (farther from the edges)

I suppose that the caniilever induce some stressing of the panel, and help the bridge to keep firmer contact at its front ( a non cantilevered bass brige would be better curved to avoid tilting probably)

Cantilever are suppose to be accepteables when they are small enough, they are also in 3 parts so to keep suplleness, an if possible curved for a more stable implantation.

That long cantilever is visibly too much. (not so large in the end, but I question its stability) being really central it stand on a part of the soundboar that transmit well low frequencies. that may give that 'blooming' basses that I notice on some of those piano types

You need to see how it stands in regard of the sounboard ribs

If you plan to reduce it , install in a similar way

It's safe to say that I don't have all the proper tools for tuning and restringing. And as I'm on a very limited budget I am not planning on restringing it at this time. The strings are still attached to the tuning pins. I have bought an inexpensive tuning kit and some replacement felt. This piano was headed for the junkyard, not only was it free but the previous owner paid the entire cost of moving it. It isn't a rare or historically valuable piano so the worse case scenario is I learn a little about how a piano works and it becomes a desk. That is not my goal though.

I like to tinker, I don't have grand plans on selling it and making this my profession. I just want to learn, which is what I've been doing thanks to all of your suggestions, reading Reblitz book and things online. I truly wish my financial situation was different and I could afford to just pay someone to do a complete restoration on a piano that was worth putting that sort of money into. But then I wished that about a lot of things and if I waited until finances were there I'd still be waiting. I would still be waiting to be able to afford piano lessons vs. teaching myself, never learned to work on cars or do blacksmithing either. Any mistakes I might make hopefully I'll learn from which is better than just safely reading about it.

Thank you again everyone for your feedback and comments. Mr. Haley, you were right about removing the bass bridge in that it could've been a destructive process. Fortunately for me the apron separated from the spacer or foot, and I wasn't trying to separate the bridge from the apron which would've resulted badly as it was screwed and glues to the apron from within. Perhaps this picture will be of use to someone later on reading this so they know how it's assembled on this particular piano.

[img]http://imgur.com/a/Zmvka#C8X1OEU[/img]
[img]http://imgur.com/a/Zmvka#wyfpE63[/img]

DO not loose the carboard shims under the key frame.

Just a suggestion : under the front part of the key, a shim that goes all along the rail is better (the same under the balance rail if possible) this is for stability, when the shims are just to regulate the height an key dip at large, they allow warping when the piano is played.

It is not really worth making a restringing by a pro, but may be you could repair the player part.

As I wrote, for normal plaling, long keys are some trouble. The piano can play but have a very soft and not very precise touch because the keys have a long leverage an they also flex.
SO your idea to repair the bass bridge is good.
You could make a few saw lines in the bridge and probably in the foot as well.

Why do you capture the tuning pins ?

In Dan's case for stability of the paper pattern that he is making.

That long cantilever is visibly too much. (not so large in the end, but I question its stability) being really central it stand on a part of the sound boar that transmit well low frequencies. that may give that 'blooming' basses that I notice on some of those piano types

I have been taught as well as tried it myself on my own restorations that the cantilever is indeed mounted onto the board in a more flexible area that enhances bass tone. It is also true that the bearing on an assembly like that will stress the soundboard unevenly - put sort of an s-curve in it.
The question becomes, why not mount a solid bridge there and shorten the strings?
I have done it with great results.

I'd like to restore the player mechanism, all the parts are there. For the time being I put those parts in a safe place and will focus on the piano. Only 3-4 keys actually play, which is likely why the owner was willing to pay the moving cost. Almost all the bridle straps are broken and the jacks were jammed under the hammer butts. The action is going to need a lot of work, though I haven't found broken shanks or flanges.

Isaac, studying the picture you sent, thank you. The saw lines would then be in the foot and bass bridge, not the apron? And the reason for doing this is to reduce the mass which is going to conduct energy or sound better? How would I know how many saw lines to use, depth & width?

Gene, in my case I'm trying to close to the original design and get this piano at least playable with minimal expense. At this point I have no idea what it sounds like. I've been cleaning the wound strings as Reblitz recommends in hopes I can still use them.

Almost all the bridle straps are broken and the jacks were jammed under the hammer butts.

When I see this it means that the bridal straps were broken when someone took the action out of the piano not knowing that replacing the action without replacing the straps would jam the jacks the way you describe. It is likely there were previous DIYers at work here.

Very possible. It was clearly refinished at some point in a haphazard manner. Another problem for both the action and the keyboard were the lead vacuum tubes that go from the spool box to the wind chest were mostly broken had fallen into the keys and action. My guess is that occurred when someone tried or did take out the player mechanism then put it back.

Should the cantilever be made of quarter sawn hard rock maple? And how would you implement the saw lines?

Thinking about the load direction I would flat saw the apron.
How was the original oriented?
What species of wood was the original?
Why not just copy the original?

the saw lines are for suppleness on small pianos, that may have some soundboard curvature ( spherical soundboard) and that use a 2 parts cantilever, not 3 as in your case.

the saw lines are located between the ribs.

When on the bridge itself they go up to half the height of the bridge.

if your base is in a soft wood this is probably not necessary.
but not a problem to make some.

Soft woods save weight on the bridge so sometime they are employed.

The minimum space between pins on the bridge is 8 mm.

I took the apron and bass bridge to a wood specialty shop today. They said both were made of the same type of maple, though couldn't say if it was hard rock maple. I did try indenting it with my fingernail and wasn't able to leave much of a mark. Orientation meaning how the grain runs? The wood grain on the apron runs parallel to the 4 cracks, so it's running vertical. I thought the grain for the bridge ran horizontal or the length, but need to lightly sand it due to the varnish to be certain.

I wrote the measurements in inches on the back of the apron and included a picture if that is helpful at all.

[img]http://imgur.com/a/Zmvka#fplUA78[/img]

When you say a "3 parts" cantilever what do you mean. Does that include the spacer and the bridge? The apron originally was a single piece before it cracked. Are the ribs the notches or indentations from the bass strings?

hello, the ribs are under the soundboard.see how is the bridge located vs them.

I am not sure the cracks are so much a problem, due to the way the brige works, may be shimming them or open them more woul pe OK (?)

But it can be fun to make a new part indeed.

The wood does not look as a very hard wood to me it may have hardened in time. (I am not a specialist in woods )

The cantilever that Fenner proposed was done with only the bridge and a support , no intermediate part, the curved shape allow to gain some lenght for the strings, locate the brige foot a little farther, but really not much ( 20 mm) and it is an exemple for a small piano.
Anyway if saw lines where to be done that would be in the bottom part of the spacer it is too difficult and I think that in the underpart of the bridge it is not so much useful in your case.

Cannot be bad anyway.

Regards

I sanded the ends in order to see the grain better. Looks like you are correct about the original apron being flat sawn and the bridge is quarter sawn.

http://imgur.com/a/Zmvka#OjMEQJw
http://imgur.com/a/Zmvka#LmWKhMu

At wood craft an older gentleman there said it was maple, he didn't say hard or soft. I will just copy the original orientation. Thank you very much!

The video below helped me to understand flat vs. quarter sawn.

http://www.youtube.com/watch?v=sVBsA1KbfY8

It's been awhile since I've updated this thread. Building the new bridge was a slow process as I was dependent on someone else's help. Plus my friend likes to work very slowly and methodical, but we finally have an exact replica of the old bridge! At least to the point where the dimensions, pin placement and angles all match. Reblitz says to burnish it with a mixture of alcohol and graphite? I've searched online and gather it means to rub something smooth, but could anyone please elaborate?

Here's a few pictures prior to routing the edges that show transferring the pinhole positions and how the angle for the pinhole were drilled. Not only was the table for the drill press placed at a 45' angle, but the bridge was then placed at a 45'.

http://i.imgur.com/7xos1g4.jpg
http://i.imgur.com/1di9i3X.jpg

Nice job. You can buy it in a small jar and it's called Acheson DAG. That said, it's not needed. It's very messy stuff IMO. Some of the high end pianos don't use it. I would just spray a thin coat of nitrocellulose lacquer or better yet conversion varnish and call it good.

Thanks Ed. I also came across this which talks about using alcohol and molybdenum disulfide powder. I have some from building kid's pinewood derby cars.

http://www.graflex.org/speed-graphic/lubricants.html

if you are concerned about the new bridge matching the others, you can also use black lacquer. It's a lot less messy than graphite.