Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Installing WNG wippens & shanks/flanges

For those of you that have experience, are there any tips you can share to make the installation go as smoothly as possible? Are there any special tools I will need? I did some PW searches and read that some shank flanges might need repinning, but not nearly as many as on a typical wooden set. I'm also curious if the WNG wips typically need any repinning, especially the rep lever. Is it also true that the ideal pinning in grams for WNG parts is different from wood?

And, lastly, is it generally a good idea to remove the hammer rest rail and go with individual hammer rests?

A tech friend has the complete sample set of WNG wippens so I'm confident I will be able to choose and order the best setup for this particular piano, but advice on making these choices is most welcome.

... If you are going to apply the heels and /or knuckles yourself (easy) get 2 tubes of glue...1 for the hammers and extra for other parts.

As far as gluing on the shanks, practice before hand. You have to get the hammer on and positioned qui ckly. I did come up with a glue application technique for the shank/hammer joint which I greatly prefer to what WNG taught.

Leave the glue in the tube, and as you work on each individual hammer, squeeze out a small 1" long ( or so)line of glue on the shank...just a single not too heavy line of glue. Then take a hobby store 1/4" ID piece of hollow aluminum tubing (these have very thin walls for hobby work)and cut/sand/whatever 1/2 the circumference off for about 1" at the end of the tube. Take the now exposed inside radius of the tube, place it on the end of the shank on the previously applied glue line and twist the tubing around the shank to spread the glue evenly around the shank. I think this works great and fast. The CA glue does not harden on the spreading tube, interestingly. If it does get globbed up a bit, it wipes easily with a paper towel.

That would solve the problem I've had gluing hammers to these things. Gluing on the hammers has been one of the main difficulties with cf hammershanks.

Ed McMorrow described another technique a while back. Simply dry-fit all of the hammers on the new shanks, line them up where you want them and put a few drops of thin CA glue at each joint. Capillary action will draw the CA glue in and the hammers are glued permanently in place. I haven't tried this myself but it does sound like a good idea.

ddf

Sohmer Model 41 cupid grand (1933)
Action ratio is high - around 6.1
Action spread is 113.5
The original reps use a low angle jack that appears to match up well with the WNG low angle jack. It also looks like I will have to modify the wippen rail with a clearance cut, no big deal.

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

>-In this position, a line drawn perpendicular to the shank, through the center of >the knuckle spline, should pass to the distal side of the jack center by a 1/8" or >so. This line is defining the jack/knuckle contact angle referred to above.

At rest, the line from the knuckle core should align with the jack center pin.

Since the dimensions lie outside of current standards, or even if they didn't I would suggest starting your action redesign by proving the stack geometry.

In setting up S&S action frames for techs of many different action design skill sets, I have found that there is a fair amount confusion about what the stack geometry is supposed to accomplish. I'm designing a class for next years Boston NEECSO called "Understanding Spread" to address this confusion.

As I see it, and I would love input from Del, Ed Foote, et al regarding the the following, the goal of the stack's geometry is to:

1-arrange for the jack to contact the knuckle at an advantageous angle with key at rest.
2-locate the jack in the rep lever window so that there is sufficient room for both escapement and aftertouch without bottoming out on the jack stop felt
3-with the jack/knuckle angle at an efficient rest angle, the jack located with sufficient room for escapement/aftertouch, and the action feet sitting elevated on the tapered or non-tapered riser blocks, arrange for the shank, at rest, to be 5mm or so off the rest felt.

As far as overall key&action leverage, within functional limits defined by the given parts, the stack has very little to do directly with defining overall key&action leverage. Leverage is primarily defined by key balance point, capstan location, knuckle distance from shank center, heel distance from whip center and shank length.

So in changing parts, you need to prove that the 3 items above can be accomplished with these new parts, on the existing or modified action frame.

To do this...

Mount a new rep flange and shank flange on the existing stack. Measure the spread. Also with the action frame mounted on the key frame and riser assembly,measure the height differential between the whip center and the shank center.

What you have just measured is, in effect, a radius of a circle(spread is a radius with the shank center the center of the radius), and where on that radius in, relation to horizontal, the whip center lies.

-Take a 1'x1'piece of mdf of other flat smooth sheet stock.

-Set a drafting compass to draw a radius that matches the spread you just measured.

-with a .050 drill bit, drill a hole 1/4" or so deep in the center of the mdf. Set one foot of the compass in that hole(that hole is your shank center location) and draw a spread arc.

-draw a line, call it line#1, through the shank center hole and roughly perpendicular to 2 sides of your 1'x1' square mdf.

-draw a line, call it line #2 parallel to the line you just drew, offset from that line by the differential you measured between shank center and whip center heights. Current standards use 2.5" as this differential, but your Sohmer might well be different.

-you'll notice that line #2 intersects the spread radius at some point. That point is your whip center location. Drill .050" hole at this whip center location.

-Take a proposed shank and whip, with a pin punch push the center out enough so that the center pin can engage the holes you drilled in the mdf. Locate the shank and whip as defined by the drilled holes.

Set the parts so jack touches the knuckle, while the shank is resting 5mm off jack rest felt. (with rest rail, you will have to transfer this felt location from the existing stack. On an integral whip with rest felt, you are all set).

-In this position, a line drawn perpendicular to the shank, through the center of the knuckle spline, should pass to the distal side of the jack center by a 1/8" or so. This line is defining the jack/knuckle contact angle referred to above.

-Also, in this position, where is the jack in the rep lever window in relation to the "score mark"...ie, is there enough room for escapement & aftertouch.

If the parts don't line up with these standards, or somewhere reasonably close to them, draw other spread arcs and differentials until things alighn properly within the stack.

Hope that's not too long and hard to understand. The point is that, rather than recite dimensions to adhere to, understanding what you are trying to achieve gives you more scope to understand the action geometry changes you are trying to make. It will allow you to understand why you should either avoid the changes or make the changes with confidence.

Jim Ialeggio

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

Since the dimensions lie outside of current standards, or even if they didn't I would suggest starting your action redesign by proving the stack geometry.

In setting up S&S action frames for techs of many different action design skill sets, I have found that there is a fair amount confusion about what the stack geometry is supposed to accomplish. I'm designing a class for next years Boston NEECSO called "Understanding Spread" to address this confusion.

As I see it, and I would love input from Del, Ed Foote, et al regarding the the following, the goal of the stack's geometry is to:

1-arrange for the jack to contact the knuckle at an advantageous angle with key at rest.
2-locate the jack in the rep lever window so that there is sufficient room for both escapement and aftertouch without bottoming out on the jack stop felt
3-with the jack/knuckle angle at an efficient rest angle, the jack located with sufficient room for escapement/aftertouch, and the action feet sitting elevated on the tapered or non-tapered riser blocks, arrange for the shank, at rest, to be 5mm or so off the rest felt.

As far as overall key&action leverage, within functional limits defined by the given parts, the stack has very little to do directly with defining overall key&action leverage. Leverage is primarily defined by key balance point, capstan location, knuckle distance from shank center, heel distance from whip center and shank length.

So in changing parts, you need to prove that the 3 items above can be accomplished with these new parts, on the existing or modified action frame.

To do this...

Mount a new rep flange and shank flange on the existing stack. Measure the spread. Also with the action frame mounted on the key frame and riser assembly,measure the height differential between the whip center and the shank center.

What you have just measured is, in effect, a radius of a circle(spread is a radius with the shank center the center of the radius), and where on that radius in, relation to horizontal, the whip center lies.

-Take a 1'x1'piece of mdf of other flat smooth sheet stock.

-Set a drafting compass to draw a radius that matches the spread you just measured.

-with a .050 drill bit, drill a hole 1/4" or so deep in the center of the mdf. Set one foot of the compass in that hole(that hole is your shank center location) and draw a spread arc.

-draw a line, call it line#1, through the shank center hole and roughly perpendicular to 2 sides of your 1'x1' square mdf.

-draw a line, call it line #2 parallel to the line you just drew, offset from that line by the differential you measured between shank center and whip center heights. Current standards use 2.5" as this differential, but your Sohmer might well be different.

-you'll notice that line #2 intersects the spread radius at some point. That point is your whip center location. Drill .050" hole at this whip center location.

-Take a proposed shank and whip, with a pin punch push the center out enough so that the center pin can engage the holes you drilled in the mdf. Locate the shank and whip as defined by the drilled holes.

Set the parts so jack touches the knuckle, while the shank is resting 5mm off jack rest felt. (with rest rail, you will have to transfer this felt location from the existing stack. On an integral whip with rest felt, you are all set).

-In this position, a line drawn perpendicular to the shank, through the center of the knuckle spline, should pass to the distal side of the jack center by a 1/8" or so. This line is defining the jack/knuckle contact angle referred to above.

-Also, in this position, where is the jack in the rep lever window in relation to the "score mark"...ie, is there enough room for escapement & aftertouch.

If the parts don't line up with these standards, or somewhere reasonably close to them, draw other spread arcs and differentials until things alighn properly within the stack.

Hope that's not too long and hard to understand. The point is that, rather than recite dimensions to adhere to, understanding what you are trying to achieve gives you more scope to understand the action geometry changes you are trying to make. It will allow you to understand why you should either avoid the changes or make the changes with confidence.

Jim Ialeggio

ps chances are the string height on this Sohmer are outside of the 7 1/4" to 7 1/2" standards. This is more reason to make sure the new parts will be able to be aligned with the various parameters defined by the existing piano.

At rest, the line from the knuckle core should align with the jack center pin.

How the jack to knuckle is located in regard to the centers line determines the amount of friction during letoff.
Indeed hammer bore is there the main element.

open jack angle helps to line the jack contact point on the button, with the line of centers, assuming the hammer bore is good, friction on the button is then at its lower.

Jon,
my take on this is that in theory, as you say, the line drawn perpendicular to the shank, through the center of the knuckle core should go through the jack center.
My suggestion for the line to be favoring the distal side of the jack center is to allow for inevitable wear. Wear, as I see it, will swing that line proximally. If the line starts, with new parts, at the jack center, wear will drive the line to the proximal side of the center, making the jack work at a mechanical disadvantage. Starting out slightly distal to the jack center will keep the jack at an advantageous angle for a longer period of time.
..no???...
Jim Ialeggio

What I find, in practice, is that getting the alignment so that the perpendicular line begins by being very slightly proximal to the jack's pin allows a longer "dwell time" in the ideal zone, rather than leaving it at the starting point.

Greetings,
If the line perpendicular to the shank, through the knuckle, crosses the centerpin of the jack, at rest, (and I am speaking of the centerline of the knuckle core to the center of the pin), the geometry is at its most efficient for transferring energy, in that there is the least amount of force vectored away from the knuckles movement around the shank center pin. From that point on, the distal arc of the jack's tip,(around the whippen center), combined with the opposing arc of the knuckle, around the shank's center, would ideally be congruent enough to keep the relative motion between them at zero, removing sliding friction. I think R. Overs is on top of that as a design principle. What I find, in practice, is that getting the alignment so that the perpendicular line begins by being very slightly proximal to the jack's pin allows a longer "dwell time" in the ideal z
Regards,

Yes, no sliding friction at the knuckle/jack interface would be ideal,

Yes, no sliding friction at the knuckle/jack interface would be ideal, but it's not the reality. I studied this effect quite closely using a Solidworks model of an action, and there's plenty of sliding. It is for this reason that people have experimented with rotating knuckles, and it is for this reason that Ron Overs changed the geometry of his action. I believe Ron's changes are both warranted and technically sound.