How to Build Speargun Shafts
By S. Baselice (From ehow)

A spear gun is great for spear fishing along barrier reefs and in coastal waters. You can land huge game fish, even when they are not biting. However, the spear gun shafts can be expensive to buy. Building your own spear gun shaft makes the sport even more enjoyable and it is something you can do with a little knowledge of metal working and the right tools.

Things You'll Need: Steel rod Bard Spring Slide ring Rope ring Drill press Grinder Welder

Step 1
Start with a length of hardened steel that is 1/2-inch in diameter and about 3-feet long.

Step 2
Grind the end of the spear gun shaft into a point. Mount the shaft into a vice and use an angle grinder to cut a 45-degree angle into one side. Then turn the shaft a quarter inch, and angle grind the next side. Repeat this until you have created a sharp point in the spear gun shaft.

Step 3
Drill a 1/16-inch hole through the spear gun shaft 5 inches from the tip. Place a barb on this hole and slide a rivet into place through the hole securing the barb in place. Tap the ends of the rivet to secure. The barb should move up and down freely.

Step 4
Drill another hole 12 inches down from the end of the barb that is also 1/16 of an inch. Now slide a spear spring onto the butt end of the spear up to this hole. Push the end of the spring into the hole and tap it into place with a hammer. Tack weld the inside to secure the spring in place.

Step 5
Place a slide ring onto the end of the spear gun shaft. Slide this all the way up to the end of the spring. This will brace against the spring mechanism in the spear gun and protect the spring on the spear.

Step 6
Drill another hole in the end of the spear, an inch from the butt, to attach your rope ring. Slide the rope ring into the hole and create a tack weld to hold this in place. Then complete your weld by using a filler bar and gas welder and completely fill in the hole with a solid weld bead.