Bechstein spring & loop AND bridle tape

[John Delacour]

At 22:49 +0000 13/3/08, David Boyce wrote:

>I tuned the 1892 Bechstein model 8 of a customer yesterday. I hadn't 
>noted it before, but the Schwander action is spring-and-loop AND 
>bridle tapes. Belt and braces!  I wonder if it really made any 
>difference.

If it's a model 8 then it's later than 1892 and more likely about 
1905.  Before that it was the model III and before that it had no 
style letter cast in the plate.

The action is by Herrburger-Schwander in Paris and was imitated by 
several other makers, who needed to produce an action that would 
satisfy the requirement, especially of the player piano, for perfect 
repetition.  The principle has been applied much earlier to the 
English grand action, notably by Brinsmead.

When the action is properly regulated the hammer will move gently 
towards the string when released from check, so that the jack returns 
positively and immediately back into the notch for a repeated blow. 
No lost motion is needed with this action.

You need to distinguish between the function of this "spring and 
loop" and the spring and loop fitted to some English pianos (eg. the 
Brinsmead upright), which did substitute for the tape and had the 
function only of pulling back the hammer and speeding up the return 
of the jack, since the loop was positioned above the notch.  In the 
HS action the tape is just as necessary as on a straightforward 
action, since the spring and loop has no tendency to pull back the 
hammer -- quite the contrary.

Incidentally the old Steinway action, when properly regulated, will 
also behave in a similar way and give good repetition, but this is 
achieved by the angle of the notch and a stronger spiral jack spring. 
Unfortunately most technicians never do properly regulate either type 
of action.  We had a tuner/repairer locally who would simply nip off 
all the springs and loops when he repaired these actions!

JD