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H.  STRAIGHTEN A CROOKED HAMMER

 

Bent or badly aligned hammers in an Upright Piano

You may have a crooked hammer after repairing a broken hammer. If so, let the repaired hammer dry for 24 hours before you do this next job.

More likely, you have looked at your hammers, and one of them is cocked round getting into the way of the one next to it as in the diagram. This hammer will hang up on the next hammer as it gets to the wire, and you may find it stuck to the next hammer when you first look into the piano.

By the way, this is mainly an upright problem, but it can happen to grands. The grand solution is entirely different from the upright hammer bending process, so skip down the page to the grand hammer aligning section.

Before we go to the solution, there is another bent hammer problem. The hammer may be bent vertically as in the diagram. The way to straighten the hammer shank, or to turn the hammer back to parallel, is with heat.

Buy one of the long nosed propane devices from WalMart which is used to start bar-b-que fires. Get your hand into the hammer area, and isolate the offending hammer from the hammer rest (we don't want to light the felt there), and get thee lighter probe into the area of the hammer shank about midway. Light the lighter, and direct the flame to the center of the hammer shank while trying not to burn your thumb. Ain't this fun?

For a hammer with the hammer head bent horizontally left or right: Burn the hammer shank until it begins to darken. Drop the lighter and grab the hammer head at once and twist it horizontally in the opposite direction from its bent position, slightly off the parallel the other way. Hold it that way for about half a minute, and let go of it. If it is not yet parallel, try again. If you went too far, heat it again very briefly to let off some tension (in the hammer shank, not you. For you, go drink a cuppa coffee). The hammer can be made to come to a perfect position. Don't over burn the shank or it could break when bending it.

For a hammer bent vertically: But your hammer is off parallel vertically, right? Well, are you ever in for it. You will have to heat the hammer shank the same way as above, but when you drop the lighter, you have to pick up a medium sized screw driver real quickly, and, pushing the top of the hammer with one hand in the direction you want to bend it, with the screw driver you have to push the middle of the hammer shank the opposite direction. Don't be scared now, it's not nearly so hard as bending iron bars at the circus.  Please do check out the illustration very carefully.

But you have to be quick, and you have to hold this tension again for at least a half minute without letting off tension, nor do you want to break the hammer. The diagram should help to show the principle. Really, it works very well, once you get the hang of it. The diagram extremes are to show the direction of work, but don't try to bend as far as the diagram implies.

Again, if you don't go far enough, use the second try method as above-- heat some more, and bend some more. Or, if too far, re-heat just a little bit and let off the tension some. Now, look there, you did it, and your didn't burn the house down.

Read the instruction below for grand hammers which are cocked and off the vertical. You may use this method to rotate an upright piano hammer also, and it will often eliminate the need to using the heat. It is more work though since you have to remove the hammer butt and flange and disconnect the bridle strap etc.

 

Badly aligned hammers in a Grand Piano

You have two hammers hanging up on each other. There is a makeshift trick, and a correct solution:

Makeshift solution.

Look through the strings down into the hammer area. Decide which of the two hammers is the one which actually moved. With a long screw driver or such tool, gently push on the hammer shank near the hammer head. If it moves, you may be able to reposition the hammer at least until the tuner comes and can do it as below. The problem is, if you get carried away, you can break something.

CAUTION: If all of the hammers are not hitting the strings correctly, but they all appear to be equally spaced, your action is hung up to the left of right. Open the piano, (See Chapter Five) and find out what is holding the action from returning to its position when the quiet pedal is not in use. Look for something caught on the side of the action opposite the return spring. Maybe the return spring is broken. It must be replaced. Also, you may need to lubricate the wood points on which the guides under the action ride, called glides. Use powered dry graphite or powered Teflon.

The above trick does not work, or a number of hammers are not centered correctly.

Look down into the action at the offending hammers. Decide which ones are wrong by raising the hammer by pushing down on the key. The hammer should be positioned evenly so that the three (or two) wires are centered to the face of the hammer. Make a note of which hammers you need to reposition, AND a note which way, left or right.

Open the piano and remove the action as in Chapter Five.

Set the action on a work area, and this job is very easy. Notice that the hammer is attached to the hammer rail with flanges and a screw. Loosen the screw of the offending hammers one at a time, and move them to the position you feel is needed to correct the problem. Tighten ALL the screws a bit if they are loose, since it may have been many years since this was done. Return the action into the piano and test your work. You may have to pull the action and do some more to get it perfect.

THIS INSTRUCTION IS ESPECIALLY FOR THOSE WHO SEND HAMMERS FOR ME TO REPAIR:
It is also for anyone with a grand hammer which is cocked to one side.

If a hammer is rotated on the shank, and the shank appears to be centered well with the shanks on the right and left of it, you must rotate the hammer so that it is perpendicular again. Remove the action as in Chapter Five. Once you have the action out, find the hammer that appears to be leaning to the side. Remove the flange on the other end end by removing the mounting screw. Now, you want to rock the flange over so that the hammer will move to the vertical. Do this by cutting a sliver of thin paper to lay under the right or left side of the flange, and replace the flange. If the hammer moves too much or too little, add more paper, or find thinner paper for your shim. This is the professional way to straighten a hammer on the vertical.

Any flange on any piano, grand or upright, may be aligned in the above manner if it will solve any problems.

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I. Loose Tuning Pins