What IS "belly work"?

...in relation to pianos, of course. The rest is between me and my personal trainer (I wish! ). This is something I've always wondered. It's not in the index to Fine's book and I haven't even had success googling it (that makes it very esoteric)!

Thanks for any and all info.

Ariel

Ariel,

I may be over generalising, but here goes. Its one of the 3 facets of piano rebuilding, distinct from action, or finish work. Usually included is the soundboard, bridges, strings and pinblock. All, or none, may be repaired or replaced at the discretion of the rebuilder.

Often the technician selling does not do this work. Instead its "subbed" out much like an auto shop might sub out machine or body work. Part of the reason for this is that it is complex like much of piano making. "Belly work" today, particularly on Steinways and Masons, frequently leads to complete soundboard replacement. The techs on the board may know better, but 30 years ago soundboard replacement was almost the sole domain of the piano manufactures. To this end the definition of belly work has changed. It formerly was a process that almost exclusively involved repairing the existing wood, which can still be considered a legitimate repair today.

Hope the expansion helped

Chris

Chris described it pretty well. The phrase "belly work" comes from one of the early methods of obtaining soundboard crown. (Still in use by some.) The soundboard panel is dried to a relatively low moisture content (around 4.0%) and glued to ribs of the same MC. When this glued-up assembly is exposed to the normal factory environment the panel begins to re-absorb moisture and the wood fibers begin to swell. At least they try to. This creates a stress interface between the panel and the ribs forcing a curve, or crown, into the assembly. I.e., it "bellies." (A concept some of us are more familiar with than are others.)

It has come to refer generally to soundboard, rib and bridge work.

Del

ChrisW and Del,

Thanks very much for your "horse's mouth" replies. I'm still a little confused, though. Chris W. seems to be referring to rebuilding exclusively (including pinblock), while Del seems to be talking about the original manufacturing process (and didn't mention the pinblock).

I'm especially curious because of the vintage, unrebuilt Steinway O I just purchased. Lately, I find myself reading any and all comments here about rebuilding (which has acquired a sudden urgent fascination for me as a topic). Here is a representative remark (paraphrase): "Well, if you do a really expert job o' bellywork on 'er she might be decent" (why does this feminine metaphor bother me? )

I thought if the soundboard was OK it often didn't need replacing (that pinblocks were more often the first to go, being usually replaced along with the strings and pins if so).

My piano - not home yet - has had its action rebuilt/reworked, and according to the expert tech's report, is in superb condition and shouldn't need anything else for decades. If it's as well maintained in our household as it has been previously, that is...But I'd still like to understand this concept a little better. After all, my piano MIGHT need something else sooner or even now.

Pianos don't have obvious bellies (I'm serious - I can't picture where the image comes from even to get a feel for it)! Confusion reigns

Ariel

The phrase originated in the factories. It is still used both there and in rebuilding/remanufacturing shops.

In our usage the phrase belly work does not include the pinblock. The pinblock can be replaced exclusive of any belly work.

If memory serves, the last Model Os were built in the early 1920s. You might want another "expert tech" check out that soundboard.

A more visual image can be formed when you watch a soundboard assembly go from flat to nicely curved -- i.e., crowned -- just sitting on the bench as it takes on moisture. Visit a piano shop that does belly work and take a look at a fully crowned soundboard assembly.

Del

Ariel,the belly of the piano refers to the acoustical inards,soundboard with bridge and ribs attached.A lot of rebuilders like to replace the soundboard with a new one when re-building a piano.Others repair the sound board by shimming the cracks.A piano that has been totally re-manufactured will have the soundboard,ribs,and bridges replaced .It will also have a new pinblock and strings,along with the action being completly re-built,new parts including hammers.If your piano is 50+,it should be alright for awhile,but eventually will need "Belly Work".

Thank you, Curry - and again to Del and ChrisW1!

This is a GREAT site! I think I get it. The process of exclusion method of identifying just it is in rebuilding, works best for me - it's simplest! It appears to be THE most expensive work one can need doing on a piano (well, refinishing can be quite variable).

I seem to remember hearing that sound-boards installation is so specialized than most rebuilders don't know how to do it, and ship it away - often quite far - for such work, even if they've done everything else.

So I see it IS kind of complicated to define - a rather fuzzy area, anyhow.

Ariel

All things are relative. Replacing pinblocks was considered rare and exotic back when I did my first one in 1964 or 1965 as well. Nowadays it's so common and essential that many rebuilders (including our own shop) refuse to “rebuild” a piano without replacing the block. The same thing is beginning happen with soundboards. As the installed fleet of pianos get older this work becomes increasingly necessary and common. We consider any soundboard more than 30 or 40 years old to be suspect. Not that we automatically replace every 30 to 40 year old board, but we sure look at them closely. As well, we’ve replaced soundboards on the occasional 5 and 10 year old piano. For similar reasons there are more and more rebuilders doing this work as a matter of course now than ever before.

Del

Ariel,

I'm glad the pro's have colored things in. Thinking of rebuilding in terms of three areas is something I admit I came to do in searching for good rebuilds. They apeared to be distinct specialties in my hunt. I don't mean to impose that as the industry view and stand corrected on pinblocks not being belly work.

One thing a well experienced tech told me was to watch Steinway 'O' candidates for signs of "bridge roll". They are just slightly more prone to it, I guess. Maybe Del can elaborate, but it can be understood by envisioning what the bridge can begin to do over time with strings pulling down upon it. I'm pretty sure in the case of the 'O' the bridge is cantilevered and that may be part of why its more suceptable to this condition. No biggie. You should just be content that the tech you chose/choose would spot it and be able to get it rectified on the off chance things aren't right.

Chris

How do these lists grab you? Just found them under a particular Google site when I scanned a little more carefully (I didn't use quotes right before, I think. But I DID bring up Lead Belly!)

Ariel


Normal work performed on piano:[/b]


ACTION WORK:

Keytops, repaired or replaced
Re-bush front and balance rail
Replace hammers, shanks and flanges
Replace repetition
Replace backchecks
Replace backrail cloth
Replace keyend felt
Sand key sticks
Polish front and balance rail pins
Clean keyframe
Replace balance rail paper and felt punchings
Polish action shift bolts
Replace front rail paper and felt punchings
Regulate action
Repace let-off buttons,screws and punchings


BELLY WORK:

Scrape and refinish action cavity
Replace or repair soundboard
New bridge caps
New pinblock
New strings bass and treble
Refinish damper heads
Replace damper felt
Regulate damper tray
Rebuild damper tray
Reguild plate
Stencil plate
Adjust downbearing
Install new leather and cloth on trapwork
Finish underneath of piano
New tuning pins


REFINISHING:

Strip off old finish
Repair damaged wood and veneer
Sand piano with 120&220 grit sandpaper
Stain wood with aniline dye stain
Paste fill piano
Coat piano with sanding sealer
Sand sealer with 220 grit sandpaper
Coat piano with lacquer
Hand rub finish with 400&600 grit paper
Pumice stone entire piano
Polish hardware and coat with lacquer
Felt case parts
Cloth on moving parts
New buttons
New decals
High polished finishes and color finishes also available.

You have to define what is meant by "bridge roll." In general, bridges don't roll. Soundboards distort and carry the bridge with them. Yes, cantilevered bass bridges can create problems, but...

If you've had an experienced technician look at the piano and give it a relatively clean bill of health and you are satisfied with the feel and sound of the piano as it is right now ... well ... why worry about it? The piano has survived this long and it will probably go on surviving for a while longer. Will it need rebuilding some day. Of course it will. But, until then, just enjoy it.

Del

Del,

RE: "bridge roll"

It wasn't my term. It was Jon Page's. I believe he was describing the scenario where the cantilevered end of the bass bridge gets closer to the board. I won't speculate as to how.

Chris

Ariel, I have done both, enjoyed the old thing as is with a bit of adjustment and then, when money was saved, did the rebuild. I have to say I enjoyed the piano thoroughly in it's unrebuilt phase. Now I truly appreciate it in it new restored form, belly work and all!

I wouldn't worry about it too much. Get it home, enjoy your son's playing and then decide what to do. You could sell it as is, pass it on to him and let him worry about it, or rebuild later for the grandkids.

Speaking of "bellywork" (OT), ChrisW1, how's yours coming? Any news?

Oh, the term is common enough -- I've used it myself. What is happening, however, is that the soundboard itself is bending and twisting in response to the stress placed on the bridge. The string load presses down on the bridge body which forces the cantilever down which twists the bridges mounting plate, or shoe, which twists the soundboard. The bass bridge through all of this time is doing exactly what it is supposed to be doing — nothing.

And don’t get me started on the evils of cantilevered bridges….

The term is also applied to tenor/treble bridges which appear to have twisted in response to the pull of the strings but which also are subject to the distortions of the soundboard. The reasons why this happens take up about a chapter….

Del