A Simple Homebrew Key

A key is a switch that is used for sending Morse code. When you press down on a key, it completes the circuit which sends your signal out into the world. If it is connected to a radio, that is. In the meantime, you can connect it to an oscillator (a fancy word for buzzer) so that you can send your signal out into the room.

If you’ve got junk, you can probably make a Morse code key out of what’s lying within the recesses of your shed or utility room.

It is one of the most basic keys that you can make and I am willing to bet that there are multiple operators there that are using similar devices. This can be made in about 15 to 30 minutes.

Supplies and Tools

  • a scrap board
  • a hacksaw blade
  • two screws
  • a saw
  • a drill
  • drill bits
  • driver bit
  • sandpaper
  • a vise and a hammer –or– two pairs of pliers

Step One: Create the Base

Get some scrap wood and cut it down to between 6in to 12in. Basically, you want it to be big enough to be solid, but not so big that it gets in the way. If you plan on mounting a code practice oscillator on the back, make it on the larger side.

If it’s too large, you can always cut more off later. Ideally, it shouldn’t be too thick either. Something in the 3/4in range should be good.

Step Two: Make the Key Lever

This involves taking a hacksaw blade–or anything else that is conductive and flexible, such as a feeler gauge blade–and cut it to a manageable size, about 4in to 6in.

To break your blade into a manageable size, you can either place your blade in a vise, hammer it flush with the jaw, then bend it back and forth with your hand. It should snap in two fairly quickly. If you don’t have a vise, get two large pairs of pliers or vise grips and bend the saw blade back and forth.

Next, put a bend in your blade so that it lifts the majority of the blade off the surface about 1/4 to 1/2 inch. I found that bending a shallower angle in the blade works the best. 90 degree angles tend to break the blades.

Step Three: Clean the Contacts

Since this blade is painted, we will need to remove the paint so that we can make a good electrical connection with our key. Take your sandpaper and remove the paint from both ends of the hacksaw blade. It is not necessary to remove all the paint from the entire blade.

Step Four: Drill a Hole in the Metal

Drilling through metal is not too terribly complicated, but it must be done properly. First, choose a drill bit that will cut a hole the same size or slightly larger than the shank of your screw.

Then, place the smaller bent end of the hacksaw blade toward the end of the board. Leave room around all sides of the hacksaw blade so that you have plenty of space to mount a code practice oscillator or other electronics. Leave the front of the board free for your hand to grip the top of the hacksaw blade where the existing hole is located.

Drill a hole into the hacksaw blade and into the board beneath. When drilling through thin metal, drill slowly and with great pressure. If you drill too quickly, heat will build up. This will create a divot in the metal and/or dull the drill bit, both of which make it impossible to cut a hole in the metal. I learned this the hard way and ruined a drill bit in the process.

Step Five: Attach the Screws

Now that you have drilled your hole, insert a screw to fasten the blade to the board. The blade should not spin around the screw upon the board.

After the blade is attached, make a mark where the existing hole is at the front. Reverse the drill to loosen the back screw slightly, then move the blade out of the way.

Next, drill a hole where you just made a mark at the front, then add a screw to the new hole below the blade. Move the blade back to its original position, then tighten the back screw again.

The blade, when depressed, should contact the front screw and spring back when released.

There you have it! A basic, yet functional homebrew key. However, every good key needs an oscillator or radio. Next, we will go over how to attach an electrical circuit to the back so that you can hear yourself practice.

I hope you enjoyed building the key and will stick around for the upcoming post about building your own oscillator. If you already have one, then you have one more step to go…

Bonus Step: Attach your Oscillator or Radio

Next, remove the two screws from your board and attach your oscillator to your key by placing the two switch wires into the holes you drilled. The ends of the wires need to be stripped.

Reinsert the screws, ensuring that bare wire is touching the metal of the screw. The circuit completes when the hacksaw blade comes down onto the front screw. Your oscillator should sound or your radio should transmit.

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