A guitar has 6 strings. When playing finger-style, you use your thumb (1) for the thickest 3 strings, and the next three fingers (2=index, 3=middle, 4=ring) for picking the next three, thinner strings. When picking the strings with a guitar pick, or plectrum, (which produces much clearer sounds), you hold the pick between your thumb and your index, so your index finger becomes unavailable for finger-style playing.

The thumbpick is basicly a pick that you can wear on your thumb, like a ring. It's a great invention, since it allows you to play both styles at the same time, giving you more creative freedom.

Because I didn't find one at my local music store, I thought why not make one myself back home? So, after playing with paper templates, I came up with a final vector template which, when cut out of a piece of plastic and properly assembled, works out just fine. I attached the vector template in the tutorial, either for printing and cutting the shape out with scissors and an xacto knife, or for CNC laser cutting.

Materials needed:

1. CD case cover - I found out this plastic has many desirable qualities: ideal thickness, plasticity and elasticity. plus, it's nicer when transparent ;)
2a. For printing-cutting: printer, scissors, xacto knife/cutter, scotch tape
2b. For CNC: well, a CNC laser cutter

Since I don't have (yet) a CNC machine, I will take you through the steps I took: printing and cutting out.

Step 1: Print and Fit the Template to the Plastic

Open up whatever file format you can use from the ones supplied at the end of the instructable, and print it - just keep in mind that it should be printed at 100% scale. Then cut it roughly around and stick it with scotch tape to the inside-curve of a piece of CD-case cover.

Step 2: Cut Out the Shape

I first cut out the outline with the scissors, and then cut out the finer details with the xacto knife. After this, I removed the template and all remaining scotch tape.

Note: when cutting the outline (exterior), be sure to keep compensating the loss of scotch tape by re-taping the edges already cut, so that the paper template would stick in place throughout the whole process.

Step 3: Tying the Knot

First, bend the plastic piece following the original bending direction, and clutch it together as shown in the first picture.

Then continue bending inwards and clutch together the two corresponding slots, as seen in picture 3.

Finally, keep bending inwards some more until you can pull out and hook up the ending hook into its corresponding slot.

That's it. The rest is just a matter of adjusting it it to your finger and going ahead to play the guitar.

Notes:

1. This template fits my finger snugly (as it should) - but you are free to adjust/scale it to fit yours.
2. It's best to print out and try out a paper template first. There's no point in cutting multiple plastic versions - so first measure, then cut.