Pianotech

I can "pre-compress" BR punchings by hammering them on my anvil and reduce their immediate thickness by roughly .010". The idea being to accelerate the compression that will happen anyway under normal circumstances and improve leveling stability.

The question is: Is this a reasonably permanent compression, or am I "shooting myself in the foot" and they'll spring back and ruin me soon?

Anybody done this, or have a better way?

Peter Grey Piano Doctor 

I can "pre-compress" BR punchings by hammering them on my anvil and reduce their immediate thickness by roughly .010". The idea being to accelerate the compression that will happen anyway under normal circumstances and improve leveling stability.

The question is: Is this a reasonably permanent compression, or am I "shooting myself in the foot" and they'll spring back and ruin me soon?

Anybody done this, or have a better way?

Peter Grey Piano Doctor 

The balance rail punchings don't often get the attention they deserve, in my estimation. The balance point / key fulcrum is where the forces in the key collide - the downward blow from the fingers on one side, and the mass, friction and inertia on the other side in resistance.

The balance rail  punching there serves to eliminate the potential of noice emanating from this point.  And more - they need to help move the energy along through the key to the wippen.

Often, the punchings are overly thick - up to 3 mm (1/8").  Playing above a medium dynamic will force this punching to compress; it acts like a shock absorber. This drains energy (power) from the system and reduces the threshold to action saturation. I always try to use a thin, firm punching at the balance rail, one which is just soft enough to avoid a key knock.

A thick punching also has the potential to compress more over time, leading to the regulation going south a lot more.

When I had Piano Forte Supply I sold balance rail punchings made of firm Crescendo felt. They were 1.4 mm thick, but beautifully firm and stable. I don't seem to see these on the current Piano Forte Supply website.
Failing that I would go for thin bushing cloth punchings, 1.0 mm.  I am not sure that trying to flatten them with a hammer is worth it. First off, there will be inconsistency from one to the next, and surely there will be "recovery" anyway.
If the punchings seem too fuzzy I have, in the past, laid them out and used a hot iron to smooth the nap.

I can "pre-compress" BR punchings by hammering them on my anvil and reduce their immediate thickness by roughly .010". The idea being to accelerate the compression that will happen anyway under normal circumstances and improve leveling stability.

The question is: Is this a reasonably permanent compression, or am I "shooting myself in the foot" and they'll spring back and ruin me soon?

Anybody done this, or have a better way?

Peter Grey Piano Doctor 

Jurgen,

On a phone call with Chris Chernobieff, he echoed your recommendation nearly to the letter. I think it makes a lot of sense. In fact I have long wondered why there was such a wide assortment of punchings used in the industry. 

I do in fact have a nearly full set of Crescendo BR punchings from long ago, in the drawer, that I have now decided to use on this current project. Good to use up stuff anyway now rather than buy new. Retirement is not that far away. 

Peter Grey Piano Doctor 

The balance rail punchings don't often get the attention they deserve, in my estimation. The balance point / key fulcrum is where the forces in the key collide - the downward blow from the fingers on one side, and the mass, friction and inertia on the other side in resistance.

The balance rail  punching there serves to eliminate the potential of noice emanating from this point.  And more - they need to help move the energy along through the key to the wippen.

Often, the punchings are overly thick - up to 3 mm (1/8").  Playing above a medium dynamic will force this punching to compress; it acts like a shock absorber. This drains energy (power) from the system and reduces the threshold to action saturation. I always try to use a thin, firm punching at the balance rail, one which is just soft enough to avoid a key knock.

A thick punching also has the potential to compress more over time, leading to the regulation going south a lot more.

When I had Piano Forte Supply I sold balance rail punchings made of firm Crescendo felt. They were 1.4 mm thick, but beautifully firm and stable. I don't seem to see these on the current Piano Forte Supply website.
Failing that I would go for thin bushing cloth punchings, 1.0 mm.  I am not sure that trying to flatten them with a hammer is worth it. First off, there will be inconsistency from one to the next, and surely there will be "recovery" anyway.
If the punchings seem too fuzzy I have, in the past, laid them out and used a hot iron to smooth the nap.

I can "pre-compress" BR punchings by hammering them on my anvil and reduce their immediate thickness by roughly .010". The idea being to accelerate the compression that will happen anyway under normal circumstances and improve leveling stability.

The question is: Is this a reasonably permanent compression, or am I "shooting myself in the foot" and they'll spring back and ruin me soon?

Anybody done this, or have a better way?

Peter Grey Piano Doctor