Sunday, March 18, 2012

Hammer butt leather

Do you hear a pronounced scratching when you play your keys?

Your butts may be losing their leather.

Side View
Looking from above

Looking at these two images you will likely see the problem.  It is relatively simple to resolve the loose leather, but be careful.  Don't use so much glue that it soaks into the leather causing another "noise" problem once the glue had dried.

I like to use a 60 second curing super glue.
Drop of Glue Applied
60-90 Second Cure "Gorilla" brand

After applying the glue, press firmly and hold in place until the glue sets.  Alternately you can hold tight with a clamp, rubber band, etc.

 Re-install part and your jacks won't be dragging along your butt leather improperly anymore!

Sunday, March 11, 2012

Broken Sustain Pedal Pivot

A customer indicated recently at a service call that her pedal was not functioning properly.  What for us a piano technician might seem like a simple repair often will seem completely confusing to you the customer.  While I will describe and show you the point of breakage with this particular pedal I will not suggest you attempt to tackle a problem like this on your own if your piano has the same features.

How do I know?

Cracked Fulcrum block
Internal Pedal Levers

If you look at the 2 pictures above you will see the inside of the piano under the keys and piano action.  This design while not common was used in the 1910-1930's or so.  To know if your piano is like this do the following:

  • Lay on your back under your piano with your shoulder to either side of the piano's pedals
  • Looking at the bottom of your piano do you see any levers or rods that are screwed to the bottom?
  • If you were to remove the pedals and legs would the bottom of the keyed (under the keys) be flat?
If the underside of the piano is flat your pedal levers are "inside" the piano.  

To assist this customer with their non-functioning pedal I removed the key slip, fall board & cheek blocks.  This allowed me access to remove the action from the piano and set to the side. Remember when removing any grand piano action to not press any keys as you slide the action out of the piano.  if you disregard this warning you are going to break a hammer or a hammer shank requiring a visit from a technician with the proper replacement part!  

Once the piano action has been removed you can see the mechanism for the pedals, and if you push the pedals can see what is happening inside and likely you will find the problem.  But as each manufacturer has had different designs it is difficult to tell you exactly how to proceed.

For the most logical approach, follow the links starting from the pedal itself up to the moving lever inside the piano.  You will likely find the problem.  In this piano.... a broken fulcrum.  The fulcrum gives the lever a fixed point to turn or pivot from.  When the pivot is broken the lever will no longer work as intended. 

For this customer I glued the crack before I began the tuning, clamping the workpiece together as the glue had some time to set.  After the tuning I replaced the now repaired piece with instructions that it was possible and even likely the piece would break again.

I took measurements of the original block so that if this piece cracks again I will be able to manufacture a part without an additional service call to the customer to remove the original piece.  When a part is manufacturer I will create 2 or more lengths of this block to use in the future should this problem occur again.

Sunday, March 4, 2012

Key Spacing

Wider Gap Between B & C
When you look at your keys do you see this?

Notice the gap or spacing between the keys, particularly between the 'B' and 'C' notes. You may also notice a clicking sound when you play certain notes, this click can be caused by too much side to side movement allowing the key to contact a neighboring key.

This piano was less than 5 years old and had not been noticed before.  There are generally 2 reasons this can occur:

  • Poor spacing from the factory
  • Poor key easing
  • Worn key bushing felt
In this instance, since it was a "new" issue with this instrument I investigated the easing of the keys first.  Discovering the side to side movement of the keys to be significant, I opted to turn the elongated front rail pin.  I generally do not like to do this, but in this instance felt it was an acceptable repair for such an new piano with key bushing replacement and proper easing to take place when the felt is worn enough to warrant replacement. 
Front Rail Pin Adjustment tool

The Process:

1. With a front rail tool seen to the right, I slip the tool under the front rail felt punchings (and under the paper punchings if there is a considerable thickness of paper punchings)
2.  Move your tool parallel to the key bed and turn the elongated pin to a point where the side to side movement in the keys is minimal yet allows the key to move without sticking or binding.
Front Rail pin being turned

This adjustment essentially will make the elongated pin more wide which restricts the side to side movement in the keys. You do not need to remove the keys.  The keys have been removed to assist in showing the key pins and the proper use of the tool.

*Make sure you are below the punchings to avoid damage to the key pin.  Damage to the pin will cause extra friction and could cause the key to stick and will prematurely wear the felt bushing*

When you have turned the front rail pins re-check your spacing, in most instances this will have corrected the majority of the uneven spacing you noticed before.

Now play each note with the sustain pedal depressed releasing the key slowly.  If any keys are slow rising to rest position you may have turned the front rail pin a bit too far. Adjust and test again.

If the spacing is still not close enough you can also "bend" the front rail pin.  Use the same tool as shown above and gently twist the tool handle in the direction you want to move the key.  I find this extremely difficult to do as you're attempting to bend the pin from the most rigid area (closest to the key bed).

You should now have more evenly spaced keys.