I have seen some pianos, even new ones, that don't have sufficient clearance. Often it's not obvious unless you observe closely. Maybe the tone on that note isn't like the others, or there's some noise, or you can actually see the damper head move in an odd way. I'm not aware of any published clearances, but I would imagine as long as they don't collide, I'd call it good. Most often this is going to occur on bass notes where the hammers are angled, and the low shoulder is closer to the damper head on one side. You might have to sand/carve off of one or the other to prevent them touching.
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Paul McCloud, RPT
Accutone Piano Service
www.AccutonePianoService.compavadasa@gmail.com------------------------------
Original Message:
Sent: 01-21-2023 18:24
From: Alden Jack
Subject: Upright hammer clearance of damper
Is there a minimum recommended clearance of the bottom shoulder of the hammer to the top edge of the damper?--
Alden L. Jack
Associate Member, Piano Technicians Guild
Phone: 435.760.3974
Noteworthy piano tuning and repair.