Checks cause hammer bounce ?

[David Skolnik]

Ric -
I'm just trying to fill in with whatever seems not to have been 
mentioned, even if it seems something too obvious to bother with:
Check solder joints of action rails
All hammer flange and action frame screws are truly tight?
Any play in the rail dowels?
Does symptom appear equally from playing any bass note? ie, less with 
notes proximate to glides?

Since it's not clear exactly how you've gone about testing, some of 
the following may be redundant.
You said you do all the bedding with the action frame on, but I would 
look at the back rail stripped down.  Could the dags in back have 
anything to do with it?  Is there any frame distortion when you 
reinstall the top action?
You said it was an older D.  How old?  New York or Hamburg?  Is the 
key frame oak? How much "crown" is there between balance rail and 
straight edge running from front rail to back?  Measure under cross 
members.  (sorry, my key frame terminology is deficient).

Can you (with some help) put pressure on the back rail while you are 
playing notes?
Wedge the hammerflange rail
Wedge between pinblock and tops of balance pins

My biggest concern in all of this is that Andre's response might be 
the most correct.  Let's solve this thing, for Andre.

David Skolnik