How many moving parts . . .

[alzado]

. . . are in the action of a grand piano?

Does anyone know?

[thalberg]

It's a LOT.   The Renner company makes the actions for most of the world's finest pianos.  Go to Rennerusa.com and you can read about it.  At one point in the site, it says there's 5700 parts in a piano mechanism.  I don't know what that means.  At another point, it offers some sort of sample action for technicians with 41 parts. 

Go see for yourself.  And if you're interested, there's a download of a real Renner action in motion.

The only other company that makes actions that I know of is Steinway, who makes their own actions.

[jeremyjchilds]

I've never taken the time to count...but for comparison, there are more moving parts in any piano action than an automobile...

[gfiore]

 Yamaha, Kawai, and Baldwin make their own actions. Detoa, a Czech company manufactures actions used in some Eastern European and Chinese pianos. Hamburg Steinway uses Renner parts, utilizing the same action design as the New York Steinway, except for a few modifications. In all, most grand actions have between 5,700 and 6,000 stationary and moving parts.

[rich_galassini]

Just to expand on this idea, there are over 12000 parts, moving and stationary, in any acoustic piano.