So you'd like to use "plastic" (polyacetal resin) snaps for cloth diapers, mama pads, bibs, clothes, and household items, but the expense of a snap press is deterring you? If you have access to a drill press, you can very easily "make" your own snap press for only the cost of the snap dies and a small piece of wood!
**WARNING: Your drill press should be a high-quality one with all metal gears. Plastic gears will be cracked and break under the pressure of pressing the snap pieces together.
A snap press works by holding a CAP and a SOCKET or STUD in place and applying force to the "prong" of the cap so that it is "smooshed" down and locked into place in the hole of the socket or stud. A drill press has straight-up-and-down motion (lining the parts up correctly), and is ideal for a "homemade" snap press because the "chuck" that accepts the drill bit will easily accept the shank of a snap die without modification.
Order snap press dies and snaps from http://www.thesnapstore.com or http://www.verybaby.com . A die set to apply the snaps will consist of 3 die pieces: a CAP die, a SOCKET die, and a STUD die. A cap will go on the opposite side of a socket or stud, adhering it to the fabric. If you "mix and match" your order of snaps (instead of buying "complete sets"), make sure you buy a number of caps equal to the combined number of studs and sockets (ie, a complete snap is made up of one stud, one socket, and two caps) for each color that you want sets of.
When your snap dies arrive, drill a hole in a piece of wood for the cap die shank to fit snugly in (you don't want the die to move around while pressing the piece together). The board with the hole drilled is shown the in the picture below. According to the information on their websites, the cap die from Very Baby has a 3/8" shank, the cap die from The Snap Store has a 1/2" shank. Put the cap die in the hole.
Put the shank of either the socket or stud die in the open chuck of the drill press. Tighten the chuck to hold the die securely. The stud die is shown in the chuck of the drill press in the picture above.
Place the piece of wood on the working surface of the drill press so that the cap die is lined up with the socket or stud die in the chuck above it. Be careful during this step, if the dies aren't centered, the snaps won't "smoosh" together properly and won't lock together. Once you have the die placed properly, use C-clamps or other strong clamps to secure the piece of wood to the working surface, being careful not to shift the wood as you clamp it.
There are two methods for marking and placing the snaps.
The first method is the "tap, tap, tap, press" method. Make a mark on the fabric where the snap is to be applied. Put a socket (or stud) piece in the upper die, and place the prong of the cap die on the mark. Settle the cap into the lower die. Keeping the fabric still, lower the press and "tap, tap, tap" with the socket piece until the cap prong pokes through the fabric and then press the pieces completely together.
In the second method, you will be making a hole for the cap prong. Use an awl and a hammer or a leather punch. You only need a very small hole, and making too large of a hole will cause the snap to pull out of the fabric. Place the cap in the die, put the prong through the hole in the fabric, and press.
Making a hole first by using one of these two methods will reduce the number of "failed" snaps--ones where the prong does not go through the fabric and is not pressed and locked into place in the hole of the stud or socket piece.
Pressing the snap pieces together.
CONGRATULATIONS, YOU'VE JUST "MADE" A SNAP PRESS! Now find some stuff that needs snapping! ;)