Baldwin SD-10 ruminations (long)

[atonal at telusplanet.net]

Greetings all, 

It's been quite a while since I've posted, although I sporadically check the list and I'm 
pleased to see the new techs along with some old-timers (mind you, 10 years is 
forever for a internet listserve).

Today's project is a 1972 Baldwin SD-10. We have acquired this piano from a local 
church that has changed venues and traded the piano on other musical equipment.

Condition of the piano is beaten. Over the years, top treble restringing has ocurred, 
hammers have been extensively hardened, critters have taken up residence in it for 
a time mauling the damper felt, and overall tone and power are bright and weak.

Leaving aside action considerations for a moment, I am now in the analysis phase of 
the soundboard and downbearing. The board is free from separations, and I have 
found no change in crown measurements from the loaded state (4-6 mm in central 
sections of the board) to unloaded. I am getting the same crown measurements with 
the strings off as with them on. 

Bearing analysis shows some whacky results. Using my newly-acquired Lowell 
Composite Bearing Gauge (shout out to Piano Tek!) The front bearing is nicely 
positive in the top two sections, zero to negative in the tenor and mid sections, and 
back to decently positive in the bass. Back bearing shows the opposite, negative in 
the top 2, positive in the centre and tenor, and positive in the bass. Now, the Accu-
Just pins won't be able to cure all of the back bearing problems, as they are at the 
bottom of the pin on the top two sections (the re-strung ones) and the rear bearing is 
still negative! Judging by feel, I can't discern any bridge roll or rippling/cracking of the 
soundboard at the bridge. So now I have to decide of I can change the plate height to 
correct these bearing problems, or if a new soundboard is in order.

Having mulled this over for the past week, the problems boil down to this:

Lowering the plate will increase front bearing in the centre where needed, but also 
severely increase the front bearing in the top, which is currently nicely positive. 
Lowering the plate will also allow me to increase rear bearing in the top treble and 
allow the Accu-Just pins to be set properly. The tenor and bass Accu-Just pins were 
near the top of the pin, and bearing was positive. If I keep the existing board, I will 
have to cant the plate, lowering the front (more on the bass side) and bringing down 
the rear on the treble side, if possible. 

As much as I'd like to pack the whole thing off to Bolduc for a new board and 
bridges, I have to make my business case to the powers that be (i.e. he who writes 
the cheques.) 

Still in the analysis phase currently, anyone with experience in resetting threaded 
plate systems please chime in.

Regards, 

Rob Kiddell RPT
Edmonton, Canada
atonal at telusplanet.net