Pianotech

Scott,

The torsion spring pictured cannot be adjusted (bent), or any spring for that matter, and expect to have any range of pressure adjustment. Bending only changes the range in which the given pressure begins and ends.  The given pressure is determined by the wire size. My read on this is to make new springs with a different wire gauge.

Roger, 

Thanks. What about modifying to take modern springs? In examining my photo, I wonder whether there would even be room because of the proximity of the shank to the spring. Drilling a hole might even put it through the shank. The spring resides in a pretty shallow recess. I'd probably have to somehow deepen the groove so the that the coil sits in a position to receive chord to hold it in place.

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Scott Cole, RPT
rvpianotuner.com
Talent, OR
(541-601-9033
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Original Message:
Sent: 10-29-2024 15:42
From: Roger Gable
Subject: Double-sprung dilemma

Scott,

The torsion spring pictured cannot be adjusted (bent), or any spring for that matter, and expect to have any range of pressure adjustment. Bending only changes the range in which the given pressure begins and ends.  The given pressure is determined by the wire size. My read on this is to make new springs with a different wire gauge.

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000

Roger, 

Thanks. What about modifying to take modern springs? In examining my photo, I wonder whether there would even be room because of the proximity of the shank to the spring. Drilling a hole might even put it through the shank. The spring resides in a pretty shallow recess. I'd probably have to somehow deepen the groove so the that the coil sits in a position to receive chord to hold it in place.

Scott,

The torsion spring pictured cannot be adjusted (bent), or any spring for that matter, and expect to have any range of pressure adjustment. Bending only changes the range in which the given pressure begins and ends.  The given pressure is determined by the wire size. My read on this is to make new springs with a different wire gauge.

Scott,

Your concern about proximity to the shank is justifiable, but from the photo it does appear to allow you to drill a hole through the side of the butt to insert a retaining center pin without encroaching into the shank. It's hard to see from the photo. Adding the Schaff 3736 mentioned by Nathan appears to be a possibility, although the wire gauge may be incorrect. You just have to try them.

P.S. I'm not sure what you mean by "modern springs"

Roger, 

Thanks. What about modifying to take modern springs? In examining my photo, I wonder whether there would even be room because of the proximity of the shank to the spring. Drilling a hole might even put it through the shank. The spring resides in a pretty shallow recess. I'd probably have to somehow deepen the groove so the that the coil sits in a position to receive chord to hold it in place.

Scott,

The torsion spring pictured cannot be adjusted (bent), or any spring for that matter, and expect to have any range of pressure adjustment. Bending only changes the range in which the given pressure begins and ends.  The given pressure is determined by the wire size. My read on this is to make new springs with a different wire gauge.