I will try to tell you how to make a simple jig for wire earrings or necklaces. I started to make earrings only with pliers but I soon realized that the more complex ones were not similar enough to call them "a pair". Then I discovered the wigJigs on http://beadstore.wigjig.com and I wanted to order, but then I thought I can save the time and money by making my own.

Materials you need (what I used):
- some pieces of harder wood (I found some already-cut rests at Baumaxx -for free, made out of some sort of very dense glued carton, almost like wood). For the 4 different jigs that I present here you will need 4 pieces of 15x15cm, or 2 pieces if you find thick enough material (>=1.8cm).
- 3mm thick iron pegs - furniture door stoppers (i found a 20pcs pack for ~3Euro/ ~4$) or anything similar (1-2cm long nails are also an option)

TIP1: don't use very thin wood since the pegs will come out on the other side and once on the table they will pop out.
TIP2: don't use soft wood (like conifers) as you won't be able to drill nice holes and the holes will bend due to the force applied to the pegs.

Tools you need:
- printer + paper
- pencil + copy paper (or some other way to transfer the pattern to the pieces of wood)
- Dremel + stander
- 3mm wood drill

Step 1: Transfer the Patterns on the Wood

Download and transfer the attached patterns on the pieces of wood as precisely as possible. If you mark only a dot in every center of the circles it would better when you use the Dremel.
I suggest you use the circle-shaped patterns for a start, since you can make some nicer designs (in my opinion).

WigJig pattern.pdf
Download

Step 2: Drill the Holes

Even if "doable" , it takes quite an effort to drill so many holes without a stander.

Measure the length of the pins you have found/bought and then set the drilling depth to that length+1mm.
Start drilling the holes. It will take you some 5-10 minutes. Then use a fine sandpaper to smooth the edges.

Step 3: Add the Pegs

Now that you have the holes, you can add the pegs in whatever pattern you will like.
I use 1mm thick / 18 gauge wire but you can also use thicker wire without spacing the holes differently.
http://en.wikipedia.org/wiki/American_wire_gauge

Disadvantages vs a new one: you don't have too many peg diameter options. You can buy 3mm and 5mm for the 3mm holes, but hey! it's a start. You can also improvise or even buy a set of thicker pegs from the jig manufacturers.

I would be glad to receive suggestions about ways to use thicker pegs with the same holes, or even jewelry patterns. Thanks.

Enjoy making new jewelry, and don't forget to use some colored beads ;)