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Regulating Hammer Blow Distance

Posted By: asb37

Regulating Hammer Blow Distance - 01/17/18 10:06 PM

I am a amateur learning how to tune and regulate pianos. I have a basic question about regulating blow distance.

When setting the blow distance in a piano, should all hammers be set to an even hammer line? If so, won't the blow distance in the bass be higher than the blow distance in the rest of the piano, given that the bass strings sit higher than the normal steel strings?

For example, in my piano, if I regulate the bass hammers to 1 3/4 in, they are higher than the rest of the hammers because the bass strings sit higher in the piano, causing an uneven hammer line.
Posted By: BDB

Re: Regulating Hammer Blow Distance - 01/17/18 10:19 PM

The hammer line is measured from the string to the tip of the hammer at rest. The tips of the bass hammers are the same distance from the string, not from the hammer rest, so the line is uneven if the piano is overstrung.
Posted By: Chris Leslie

Re: Regulating Hammer Blow Distance - 01/17/18 10:23 PM

If you look at the hammers you will see that the bass hammers are indeed set back relative to the treble hammers by the same amount as the strings are.
Posted By: asb37

Re: Regulating Hammer Blow Distance - 01/18/18 01:34 AM

Thanks for the replies.

In my piano, the entire line of hammers was set even, so the travel for the bass hammers was 2 in, and the rest of the piano 1 3/4in or so.

So, the proper regulation would be to set the bass hammers to 1 3/4 in, correct? In this case, the bass hammers will be 1/4 in or so higher than the rest of the hammers. This piano is overstrung.

Posted By: BDB

Re: Regulating Hammer Blow Distance - 01/18/18 02:08 AM

What make of piano is it? That much of a difference in the hammer blow would make a big difference in the playability.
Posted By: asb37

Re: Regulating Hammer Blow Distance - 01/18/18 03:58 PM

It is a 1998 M&H model A. I feel like it takes a lot of work to play in the lower octaves, so I was experimenting with a shorter blow distance. (I've also measured down weight, friction etc.)

The blow distance in the bass hammers was a little over two inches. The weird thing is, if I actually set it at 1 3/4 in, the hammers contact the frame when I slide the action out. I'm able to get it out because they bend downward easily, but it makes me nervous keeping them set like that, so I added some blow distance. Clearly this piano wasn't designed for a 1 3/4 in blow distance in this section.
Posted By: Ed A. Hall

Re: Regulating Hammer Blow Distance - 01/18/18 05:06 PM

Originally Posted by asb37
The weird thing is, if I actually set it at 1 3/4 in, the hammers contact the frame when I slide the action out. I'm able to get it out because they bend downward easily, but it makes me nervous keeping them set like that, so I added some blow distance. Clearly this piano wasn't designed for a 1 3/4 in blow distance in this section.



This is actually quite common. You might try a blow distance of 1 7/8 in.
Posted By: asb37

Re: Regulating Hammer Blow Distance - 01/18/18 06:35 PM

Originally Posted by Ed A. Hall
Originally Posted by asb37
The weird thing is, if I actually set it at 1 3/4 in, the hammers contact the frame when I slide the action out. I'm able to get it out because they bend downward easily, but it makes me nervous keeping them set like that, so I added some blow distance. Clearly this piano wasn't designed for a 1 3/4 in blow distance in this section.



This is actually quite common. You might try a blow distance of 1 7/8 in.


Thank you for replying. That clears things up. I appreciate it!
Posted By: Bill Bremmer RPT

Re: Regulating Hammer Blow Distance - 01/19/18 03:41 AM

I never actually measure the blow distance with a ruler. In my view, that is the wrong way to approach the setting. But I can say this: 1 3/4" is way too short. You need to learn more about after touch. When you do, you will discover the right way to set the blow distance.
Posted By: Gerry Johnston

Re: Regulating Hammer Blow Distance - 01/19/18 04:29 AM

Bill Bremmer is correct. Hammer blow distance can vary a bit without having a negative effect on the action. Pay more attention to after touch along with key dip and let off. If these are correct the hammer blow distance might just take care of itself.
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