Intro: Chainmaille 101: Locking Clasp
The first step it to cut your self about a 6 in piece of wire, I prefer 20 gauge or somewhere in that area.
Next put a "V" shape into the wire about 1 inch to 3/4 of an inch down, like so.
Continue down the wire about another 1 - .75 inchs and fold the whole top over.
Now we loop it back again going over the other side, be sure to keep it tight to the end or you may get snagged up.
Now at this point if you wanted you could solder the center solid but for the purposes of this tut we're not doing that.
Moving on. Now you fold the top down like you would any other clasp but this time you want it to almost touch that little bump you put in it in the first step
Now roll over the back side.
Now I don't show it here but if you cut your piece of wire long enough..unlike me then you can roll it around the hole thing a few times for a little wire finishing and gussing up. Like seen in the second one in the pic above.