On the Hook with Heat Treatment
To fish, you need the right equipment, which definitely includes a hook. Have you noticed there are hooks of various sizes and shapes, some with barbs and some without? Why do the differences exist?
The basic fish-hook concept has been used for thousands of years. The earliest documented fish hook was found in Palestine and dates from about 9,000 years ago. Steel hooks came on the scene in Europe in the 1600s, and hook making quickly became a bit of an art. Without getting too detailed, the normal hook has an eye, shank, bend, point and a barb. They are typically manufactured from high-carbon, vanadium-alloyed or stainless steel. Fish hooks are usually coated for corrosion resistance with anything from a clear lacquer to gold.
The specific applications determine the different hook shapes, materials, points, barbs and eye type. For instance, a fly hook – for obvious reasons – must be lightweight. Hooks can be single, double or treble. For each hook type, there is a range of sizes. Hook sizes are all referenced from “0.” A 4/0 is larger than a “0” with a 20/0 being the largest. Hooks can also be smaller than a “0.” For instance, a “6” is smaller than a “0,” and a 32 is the smallest made. Some of the larger hooks are even made with a ball-bearing swivel, which allows the hook to move with the fish.
The size of the hook is not usually a function of the size of the targeted fish. It has more to do with the size of the bait. Of course, the larger the bait, the larger the fish. If a hook straightens during a fight, it usually has less to do with the hook size and more to do with the hook quality. Stainless steel hooks – while expensive – are softer and tend to bend more easily and lose their sharpness.
Did you know that barbs were initially introduced to keep the bait from coming off, not to keep the fish on? In fact, barbless hooks are easier to set, and they are clearly easier to remove. Another factor in your choice of a barbed hook is your ability to keep the hook out of your own skin. If you are prone to hooking yourself, go with the barbless hook.
Most of the higher-quality hooks are advertised as being made from heat-treated, high-carbon steel. The heat treatment is designed to make the hook super strong but not brittle. Some manufacturers advertise that each hook style and size has its own optimized computer-controlled heat-treat recipe. While this heat treatment is usually not discussed – for proprietary reasons – it involves the conventional hardening and temper. The hardening cycle optimizes the strength for the material/application, and the temper creates the proper balance between hardness and ductility.
Prior to hardening, the points and the barbs are formed via forging. Sharpening can be performed with a normal needle-grinding method. After heat treatment, some hooks are further sharpened chemically. In this process, the chemical refines the point by smoothing or eating away the metal. Be aware that trying to sharpen hooks that have been chemically or laser sharpened will actually make them less sharp.
Another outdoor activity using “fish hooks” is rock climbing. Although not intended to catch fish, they are called fish hooks. This equipment is manufactured from 4130 steel and hot formed to a diameter of 2 inches. The tip is hand ground, and the final heat treatment is again designed for the proper balance of strength and ductility to be able to support the climber regardless of the pitch of the climb.
No matter which activity has you using fish hooks, you can be assured that heat treatment played a role in your outdoor fun.