Technical Tuesday - Hammer Assembly, Part 1

This week it's all about the piano hammer assembly and it's parts 'n pieces. Let's work our way down from the hammer head to the flange:

There are 88 of these little babies on most pianos, whether you have a grand or vertical.  For our discussion here, all pictures are from a grand piano hammer assembly.  Let's take a closer look at each part and what it is:

Hammer Head:  The hammer head consists of a wooden core (can be made of different types of wood), and the dense material known as the felt.  Hammer heads are not all created equal, as there different qualities and densities of felt.  The hammer head is generally ovoid in shape, and attached to the wooden core either by adhesive and/or a very small staple.  As you can see from the pictures, some hammers have a second layer of 'underfelting' which departs an additional tonal quality to the hammer head. 

The felt material that makes up the hammer's head is vitally important, as it is a contributing factor to the voice of the piano (more on this in Part 2 next week).

Hammer Shank:  A flexible, traditionally round shaped shaft that brings the head of the hammer to the proper placing when striking the string.  Shanks can also be made of differing types of wood.  Some are even now available in a carbon fiber material (zoom, zoom!).  Shanks vary in dimension and size, depending on the manufacturer's design of the piano action as a whole.

Knuckle:  (Knuckle applies to grand pianos; the comparable component on a vertical piano is the Butt)  A small round component, the knuckle is located at the lower end of the hammer shank and is traditionally covered in buckskin.  The knuckle rests on top of the jack, which controls the velocity of the movement of the hammer from its resting point to the point where it strikes the string.  The velocity of this movement is determined by the speed and pressure applied to the piano keys by the player.

Hammer Flange:  This is an important piece of this puzzle, as it holds the entire hammer assembly in place on the action rail for correct alignment, assuring the hammer will strike the string(s) in precisely the correct place for optimum touch and tone.

So, there you have it - Piano Hammer Assembly 101.  Now that we've identified the components, we'll get a little more in depth next week in Part 2.

"The Disclaimer"  Technical Tuesdays are intended to give folks who are curious about pianos a bit more understanding of all those technical terms  thrown about by technicians.  This is not intended for super in depth micro measurements, just general knowledge for those who are interested in how a piano works.