[pianotech] Pinblock expensive experiment

[Terry Farrell]

You could simply resaw the capped block in half, flip the bottom over  
(top to bottom), clamp it together and see if that straightens things  
out. If it does look better, just glue it back together (I recommend  
either epoxy or two-part urea-formaldehyde). And even if it doesn't  
straighten it out perfectly, you can try again (only hopefully better  
this time!) to induce a little counter-bend to it that makes it end up  
straight. Will only cost you a little adhesive. And like David Love  
pointed out, the small loss of thickness from the saw kerf, you can  
make up with shims - or if you want that full thickness, simply  
laminate a layer or maple (or really any hardwood) to the bottom of  
the block to make up the full thickness.

And if you end up screwing it up again, resaw the darn thing again and  
glue it back up!

No problems mate! No reason to buy a new pinblock!!!

Terry Farrell

On Apr 4, 2010, at 1:31 PM, Duane McGuire wrote:

> I think that my first grand pinblock replacement has become an  
> expensive experiment.
>
> I wanted to do the multi-lam capped with delignit block that Ron  
> Nossaman described at Grand Rapids and was documented in the  
> journal.   I resawed the delignit and planed a 9mm cap for the block.
>
> Before gluing up I noted that the multi-lam  (Schaff) was not  
> exactly flat, but I did not measure its degree of bow (I believe  
> this is the root an expensive mistake). I selected a clamping caul  
> with a compensating bow, and glued the assembly up, thinking that it  
> would tend to flatten out.
>
> After unclamping and planing the multilam to final thickness per the  
> original block,  I find that the bow in the board is just plain  
> awful.  Total deflection measured at the midpoint of the board is 10  
> mm!  I'm thinking I have some more firewood for next winter.
>
> By the way, the original block measures 39.6 mm, and from my look at  
> the suppliers, Bulduc's 1-5/8 is the only material that will match  
> that thickness.   At the same time, I do suppose a person could  
> place blocking at the ends, and use a somewhat thinner board.  From  
> my starting, I didn't find that idea appealing, but I'm looking at  
> this from every direction now.
>
> Right now my thought is that tomorrow I order a Bolduc pinblock and  
> get on with it.
>
> But rather than just reacting to my own self-pity, I'd appreciate  
> your input, before my wallet gets even thinner.   In the category of  
> self recrimination, I expect that I should have measured the bow in  
> that multi-lam and shipped it back when I found the degree of  
> deflection that was present.
>
> Thoughts?
>
>
> -- 
> Duane McGuire
> 801-830-5858
> http://blog.duanemcguire.com

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