Trying to type anything on it would be a nightmare.
Although you can play The Secretary's Nightmare in different ways, such as by dragging pieces of mattress foam over it, my favorite way is to strike it with a ping pong ball on a string. The old "Follow the bouncing ball" song cartoons come to mind as the ball ricochets off the typewriter parts.
The music it makes is always somewhat out of control and random. Because the sounds it makes are low-volume, I use a stethoscope as a means of amplification. Playing it is a very personal experience. People without the stethoscope only hear a weak suggestion of what goes on inside it.
Be sure to listen to the audio file in the last step of this instructable to here what The Secretary's Nightmare sounds like.
Step 1: THE HOLLOW STEEL BALL
Unfortunately, during the process of welding on the typewriter parts, the mirror plating was damaged. The surface now is painted.
For some reason, the notes made by The Secretary's Nightmare linger a long time. I don't know if the sphere shape has anything to do with that, but it might.
Step 2: THE TYPEWRITER PARTS
Other factors such as diameter being the same, a short rod will vibrate faster and create a note of higher pitch than a long rod will. The same holds true of strings on string instruments.
The parts started out basically flat. I bent them in different ways to make them more visually interesting and welded them with an oxyacetylene torch to the hollow steel ball I found. It reminds me of a round head with a crazy hairdo.
Step 3: THE STETHOSCOPE
When you start listening to the world through a stethoscope, you hear all sorts of things you never were aware of.
Step 4: THE BOUNCING BALL
The way the ball ricochets off the keys, rapidly striking more than one key, and the slow fade-away of each note allows notes to pile up on one another. The result is a rich complexity of sound.
Since the ball is somewhat out of control, it is virtually impossible to repeat the same music a second time. That makes each time you hear the instrument a unique and special experience.
To strengthen the attachment point of the string to the ping-pong ball, I used a small vinyl patch that the string passes through. It covers a tangle of string glued to the ball and provides more surface area for the glue to adhere to than the string alone provides.
Step 5: THE BASE
Step 6: PLAYING THE SECRETARY'S NIGHTMARE
Step 7: VARIATIONS ON THE STETHOSCOPE INSTRUMENT THEME
The attached photos are of stethoscope sculptures I made many years ago.
The one on the truck bed had the stethoscope listening to the pipe, an old drive shaft. It had an acoustic "microphone" that conducted the voice to the inside of the pipe. One flat array of rods of different lengths was struck with small drumsticks. A curved array of rods was played with a violin bow and sounded like electronic feedback. There was also a set of strings attached to the base pipe that sounded like a harp.
The other instrument, played by a friend, had a gurgle sound made by blowing air into a reservoir of liquid inside it. A "dandelion" shape of rods on top sounded similar to The Secretary's Nightmare. It also had a squeaky wheel.