There are lots of different ways to make a Diddley Bow. Some are electric, some are acoustic, but all of them are cool, fun, and easy to make.

Step 1: Supplies

Supply List for your Diddley Bow

One 2X4 or other piece of scrap wood from a wooden pallet cut to 36 inches long.
One Low E Guitar String
One guitar neck tuning key
One light T hinge
One small inner diameter washer
Two small corner brackets
Screws for hinges and brackets

Step 2: Tools to Make Your Diddley Bow

Drilldriver for holes and sinking screws
Assorted drillbits
Jigsaw
Combination square and T square or straight edge
Marking Pencils and pens (not shown)

Step 3: Preparing Your Board

A Diddley Bow is basically just the neck of a guitar with one string. It's played with a slide of any kind. Most people use an old bottle or piece of PVC pipe to slide along the string, but we even had fun with an old pair of pliers sliding the head along the string to make notes.

Begin by cutting your board to 36 inches
You can sand your board smooth but it's not really necessary
mark the centerline of your board. All of your pieces with be placed on the center line.

Step 4: Marking Your Scale Length

In order to play notes like on a guitar, you'll need to figure out the scale length for your Diddley Bow. This is the distance between the top "nut" and the "bridge/saddle" of a guitar. Its the top and bottom point where a string is stretched to make a scale. We had a guitar in the house, so we placed our board along the neck of the guitar and marked the position of the nut and bridge as well as the position of the frets along the neck. Once this is done you should use your combination square to accurately draw fret lines across your board. These will be the positions of the notes in your musical scale.

Mark nut and bridge position on your board
mark fret positions
draw fret positions across your board.

Note: If you don't have a guitar at home, you can find printable scale length templates online.

Step 5: Building the Bridge End

The bottom end of the Diddley Bow (The Bridge end) is the bottom attachment point for the guitar string including the "bridge." Carefully line up one corner bracket along the middle line making sure that the vertical part of the bracket is at the exact marked location of the bridge (scale end). Its important to be accurate or your scale notes won't sound right. Attach the corner bracket (bridge) with screws.

Line up the light T hinge behind the bridge, also along the middle line of your board and attach with screws. This is the anchor point for your guitar string. Our E string had a small metal cylinder at the bottom end that was larger than the hole on the hinge, We also used a small washer to make sure the string would stay anchored.

Align and attach bridge (corner bracket)
Align and attach bottom string anchor (light T hinge and washer)

Step 6: Building the Tunable Head

This was the hardest part of the project. First, carefully align and attach the second corner bracket at the marked top end position of your musical scale. Drill a centerline hole for the tuning key post. We used a 1 inch drill bit but all tuning keys are a little different. Make the hole large enough that you can thread your string once the tuning key has been attached. We got our guitar neck tuning key from a local music store to allow us to tune our string; it was free from a spare parts box. Everything important is along the middle line of the Diddley Bow, so you'll need to cut out the edge of your board so that the guitar string hole on the tuning key post lines up along the middle line. Once the edge has been cut with a jigsaw, drill a small hole sideways into the larger top hole to accommodate the tuning key post. We did a lot of estimation and "eyeballing" to get the key to fit, but with a little trial and error it was not to difficult.

Position and attach second corner bracket at top end of marked scale
drill centerline hole for tuning key
mark and cut a cutout line to allow alignment of tuning key
drill side hole for tuning key post and attach.
insert tuning key post into drilled side hole, and attach with tuning key hardware.

Step 7: String and Tune Your Diddley Bow

The guitar string for the Diddley Bow is run through the underside of the bottom anchor across the bottom bridge, over the marked fret lines and then stretched across the top edge bracket. Insert the top end of the string into the hole in the tuning key post and pull as taught as possible before beginning to turn the tuning key. You may need to cut off some excess length from the string before you begin to turn your tuning key.

The link below is an online instrument tuner, You can use the website to tune your guitar string to a low E note. continue to twist the tuning key until the string plays an E note.

https://www.alexdemartos.es/wtuner/

Now comes the fun, Take any smooth and hard plastic or metal object and place it on a fret line of your new Diddley Bow to play notes on your new home made guitar scale. You can either strum or pick the string with your fingers or a guitar pick, or you can use any pencil or chopstick to strike the string.