Clasps 101
The foundations of your piece (stringing supplies, clasps) are among the family of jewelry supplies known as "findings". Findings also include earring wires and posts, and other "basic" things that you need to create jewelry, no matter what kind.
Let's talk clasps, shall we?
There are several types of clasps. What kind you chose to use on a piece is totally up to you. Keep in mind who the piece is for (if you know) and don't forget design! A 22mm round toggle that might look great on a chunky bracelet will look totally out of place on a strand of 4mm Swarovski crystals.
There are pluses and minus to all types of clasps. Here are some of the basics (there are a million clasps, but I'll just outline the most commonly used.)
Spring Rings: basic basic. Cheap to buy, usually pretty easy to put on. Butt ugly usually.
Lobster clasps: Lobsters come in a variety of styles, sizes and colors. I like them a lot...they are a step up from Spring Rings, and more "secure" than a toggle (although I am getting less leary of toggles). Lobsters are now sold in some fun and fancy shapes.look for lobsters shaped like hearts, dolphins, dragons as well as the basic trigger version.
Toggles also come in a host of sizes, styles, colors, etc., When you make a toggle bracelet, you MUST make it a little snug so that it will not come unfastened. Make sure if you are buying toggles in a store that you look at the length of the bar that will fit in the other piece. If it's tiny and has little overlap, it's going to fall off. Guaranteed. Toggles work great on necklaces too...in fact, many people are wearing a fancy toggle at the FRONT of their necklaces, much like a delicate pendant.
Magnetic clasps, I've found, are hit and miss. I found some at Hobby Lobby for .99 each that have the best hold I can find. I've heard that Fire Mountain has some that are very good as well (I have some on order, so can report back later.) They are GREAT if you have difficulty fastening bracelets. Magnetics come in a variety of sizes and shapes. Pregnant women and those with pacemakers should not wear magnetic clasps.
As I said, there are a number of other styles of clasps...hooks, sleeves, so many that I can't even go into them all! These basics are good to start your collection.