[CAUT] Baldwin SD-10 questions

[Ron Nossaman]

> After years of rebuilding 'every other kind of piano', I have recently 
> invited a 1969 Baldwin SD-10 into my workshop.  This will be a first in 
> dealing with the patented plate suspension system and the accujust hitch 
> pins.  This piano suffers from several things:  snapping tight tuning 
> pins (I believe Baldwin has a reputation for this?), poor tone and 
> 'sizzling' noises in the capo region (what are those machined pieces 
> called, which bolt to the underside of the capo?).   I love a challenge 
> and am in the process of studying what literature I can find on these 
> unique instruments.  Several questions immediately spring to mind:
> 
> Although I don't normally adhere to 'hard-and-fast' rules, I learned 
> long ago (the hard way) that it is generally false economy not to 
> replace the pinblock when the plate is out (for soundboard and bridge 
> reconditioning).  However, the pins are so tight on this piano, that I'm 
> wondering if there might be merit in re-using the block, possibly with 
> the same size pins?  Or, reaming for 3/0?  Not sure why I'm trying to 
> talk myself out of a new block (it's in the budget anyway) as I 
> particularly enjoy this process.

That's not a pinblock, and never will be. Replace it with 
something that works.


> Secondly, those machined capo pieces appear to have a radius at the 
> string contact point, quite a bit larger than other pianos.  I once 
> treated the sizzling strings on this piano by tapping them sideways and 
> back into position.  This nearly eliminated all noises but it didn't 
> last long.  What are your feelings on grinding a smaller radius on these 
> pieces or does case hardening preclude this?  The few times I have 
> departed from a manufacturer's original design, it was only with great 
> trepidation but a solid conviction that it was the only solution to the 
> problem.

It might help, but I'm not sure that's the problem. That front 
duplex segment is about 43mm long, with what looks to be 
somewhere around a 15° bearing angle. I'd expect that 
combination to eventually make noise. I have an SD-10 in 
progress at the moment, and I plan on laying a brass half 
round in behind that bearing, making the bearing angle 
slightly less, but shortening the "duplex" segment to around 
10mm. I think that'll work without modifying those termination 
pieces, which are harder than an eight legged by-god. I'll let 
you all know what I finally do and how it works out. I'm just 
now cutting out ribs, so it'll be a while.


> Thirdly, the question of re-stringing on accujust hitch pins.  In the 
> absence of specialized tools/jigs to measure bearing I can think of 
> several ways to at least get the strings back to their original 
> positions on the pins (digital calipers as depth gauge?)  However, 
> perhaps this is an ideal opportunity to establish uniform bearing (if it 
> didn't exist previously).  Although I have the Lowell downbearing gauge, 
> I find it rather cumbersome and unwieldy.  On the several soundboard 
> replacements I have done, I have simply established bearing with a 
> string and thickness gauges.  How about a rocker bearing gauge and 
> feeler gauges?

Take bearing measurements, angular, not string height on the 
hitch pin, before tear down to see what you have going in. 
This should already be a standard part of your tear down 
procedure. You might find that you don't care to reproduce 
what was there.


> Fourthly, the question of the plate suspension bolts.  Actually, I just 
> blundered onto Nick Gravagne's article in the reprint book (Pinblocks 
> and Plates) which, as most of his writing does, de-mystifies the process 
> of relocating the plate.  Any additional advice to offer prior to 
> teardown and subsequent re-installation?
> 
> 
> Thanks and best regards to all,
> 
> Stan Kroeker, RPT

Just one. If, which is likely, most of the poor tone you 
mentioned in the capo region is the soundboard and not the 
termination pieces, it'll still be there after the rebuild 
with the old "reconditioned" soundboard.

Ron N