Tutorial with Photos.
Tools you will need:
Super Glue - gel type Jeweler's Saw with Fine Metal Saw Blade Anvil and Hammer for Metal Metal Files Small Carbide Drills Jewelry Nipper Pliers for cutting wire Jewelry Round Nose Pliers Jewelry Flat Nose Pliers with No Serrated Blades A Piece of 1/16" Wide Brass Tube 1 Brass Head Pin (I used a Flat Head Pin) Most of these tools can be gotten at https://www.micromark.com
The 1/16" wide brass tube. The hole of the tube should be just big enough for the head pin wire to fit into it. Use the Metal Files (or a nail file) and flatten the top so that it does not have any jagged edges.
The head pin with a fairly long tail.
File the tube at the top almost half way through. This filing is about 1/4" long.
Clean out the thin piece of brass from the tube. It should come out easily. I used my round pliers for this and cleaned the edges just a little with a file.
This is what it should look like from the side.
Use the round nose pliers and form it like this. This takes a bit of practice. Go slowly and start the pliers at the tip of the tube and roll them to make a circular shape.
Still using the round nose pliers, bend the tip slightly back like this. If it breaks off - you'll have to do this piece over. Go slowly.
Using the jeweler's saw, cut this piece off. File the bottom flat and pretty. You can make the barrel of the snap as long as you want. This one is almost too short.
Now for the head pin. Put it on the anvil and flatten the end opposite the head with a small hammer.
Flattened. Leave a little tail on one side. Make the flattened part wider than the head pin wire. The next step is to drill a hole in the widest part of the flattened area. The hole should be big enough to let the head pin wire go through it.
Cut the flattened piece off the head pin with the hole in the middle.
Use the round nose pliers to form this piece into a circle. I clamp my pliers over the hole and use the flat nose pliers to form the piece over the round nose pliers.
This is what it looks like from the side.
Fit the head pin through the circle like this.
Cut another really tiny piece of flattened brass to look like the piece on the right in this photo.
Super glue the tiny piece to the side of the snap where the catch would be. After the glue is 100% set and dry, shape the tiny piece with a file.
Super glue the head pin in the circle as shown. Also glue where the ring comes together. You can solder this but it's easier to glue it. The lead rope will cover the space. Cut the head pin to about 1/4 inch and coat one side of the pin with glue. Let the glue set and dry 100% before the next steps. You now have a top and a bottom to your snap.
Insert the pin into the top part until it meets with the bent part. The head pin should fit tightly in the tube, so be careful. Twist it and work it in. Some of the dried glue may scrape off the head pin while fitting. That's OK just clean it off. If the head pin is not tight enough - take it out and add a little more glue, let cure and fit it again. Cut the wire so that it meets the top part of the snap (this one was cut a little too short) then bend the wire a little so it doesn't fall out of the snap. The snap can be opened and closed by gently pulling the bottom ring to slide the head pin up and down in the tube. The bottom ring will also swivel. If you want the snap not to move or swivel, you can glue the head pin in the tube. Leave enough space between head pin and top of the snap to hook the snap onto the halter or other pieces of tack.
Here is a snap with a longer barrel and the lead rope attached.