Basic Action Design/Performance Question

Ron Overs sec@overspianos.com.au
Tue, 25 Sep 2001 23:26:01 +1000


John Delacour wrote;

>. . . The friction (and weight, tending to friction) inherent in the 
>design of the EH action and aggravated by the increase in hammer 
>weight after 1850, is considerable and can be reduced only to a 
>certain point.  The only significant improvement in the geometry of 
>the intermediate lever was made by Herrburger of Paris about 1900 
>and was adopted by very few makers.

Where is there an illustration of this action? Does anybody have a 
jpeg to post to the list? JD?

>. . Any preference for hornbeam v. maple would also need to be 
>justified and I'd be interested to hear this, since it's a question 
>I've often wondered about to no good end.

Hornbeam is much easier to drill center pin holes which are more or 
less square. Maple is very difficult to drill since the medullary ray 
tends to cause the drill to wander (speaking from experience).

>So far as the intermediate lever is concerned, I've seen no evidence 
>that either wood is better than the other and prefer hornbeam only 
>for its cleaner and smoother texture.

As long as the repetition lever center is located in the correct 
position (to minimise friction - and it isn't in the Renner/Steinway 
style of action), it matters little which wood is used.

>Reduced to essentials, the action consists of nothing but points, 
>each of which consists of contacting surfaces.

Sure, but in the case of the majority of contemporary actions, little 
attention has been given to friction control. The roller/knuckle 
contact scrubs badly since the contact is around 8 mm below the line 
of centers at the rest position.

>It is the positioning of these points and the management of the 
>coefficient of friction of the contacting surfaces that is critical 
>in the production of a good touch, and it in these two respects that 
>makers and/or grand finishers . .

. . . .  generally give little or no consideration to good design. 
It's 'carry on marketing' as usual, while 'ignorance is bliss'.

>. . You might think that the Steinway tubular action frame restricts 
>the finisher's geometrical excursions, but anyone who has fitted a 
>new Kluge keyboard to an existing action has been made painfully 
>aware of the amount of geometry that lies outside that frame.

Well yes, provided that tubular rails are located in the correct 
relationship the action stack may work as intended. However, the 
tubular action frame is a relatively weak assembly, which is not 
particularly efficient at holding the action components in their 
correct relationship during heavy playing. I just can't understand 
how any designer could be convinced that it is a sound idea. We've 
replaced split tubular action rails with milled rails of solid brass, 
tapped for machine screws. It seems to work quite well, but its a lot 
of trouble. At least it won't split open in response to moisture 
exposure. As for the relationship of the Steinway wippen with the key 
board, I'm not sure about their 'one wippen heel fits all' philosophy.

For those who played our piano in Reno (with a new action design JD), 
we are getting very favourable reviews with our 225 piano no. 003, on 
trial at the Sydney Conservatorium of Music this week (we're 
delighted that it is being tested against a Yamaha CF3 and a Steinway 
D). I still haven't measured the action upweight/ downweight since 
returning from Reno (and after removing the air travel corrosion off 
the capstans). Will measure and post these figures to the list over 
the next couple of weeks.

Ron O
-- 
Overs Pianos
Sydney Australia
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Web site: http://www.overspianos.com.au
Email:     mailto:ron@overspianos.com.au
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