Shaft
A wire shaft is the backbone that supports the other components of your spinner. It's made of spring or super stainless steel with the premium stainless delivering a higher tensile strength and better vibration characteristics. You can buy stainless wire in wire forms, straight pieces and coils. Wire forms are pre-bent to save you time and they come in an "R" eye or a "Twisted" eye configuration (the eye is where your hook or split ring is attached).
Spinner Blade
The blade is the primary component of a spinner. The size and shape used is determined by the fish being targeting. Among the available shapes are the kidney, willow leaf, June bug, Indiana, propeller and Colorado blades. The willow leaf works well in clear water and the Colorado is a good match for murky water conditions. The Indiana blade falls in between. Sizes range from number 00 to 7.
The lower numbers match small blades that attract pan fish like bluegill. The higher numbers match larger blades that work well with game fish like bass and lake trout. Blades typically are made from plated brass or painted steel, but some are also made from mussel or pearl shells. Plated blades should be lacquer coated to preserve the finish.
Clevis
The clevis is a U-shaped metal coupler that has a hole in each end. The blade slides onto the clevis and the wire shaft is threaded through the clevis holes. This allows the spinner blade to rotate freely around the shaft.
Clevises are shaped in two ways, and they come in four common sizes. CL1 and 2 clevises are designed for number 3 or smaller blades. CL3 and 4 clevises work for number 4 or bigger blades. The important thing is to make sure the clevis hole diameter is larger than the spinner shaft.
Beads and Body Forms
Brass body forms provide a bearing surface for the clevis and some needed weight for casting. They come in many shapes and sizes with a painted or plated finish. If you need only a spinner for trolling, a metal bead can provide the bearing surface the clevis can rest on, and you can do without a body form. Beads also work as spacers to separate blades when more than one is used.
Split Ring
The split ring is attached to the eye of the wire shaft and the hook is attached to it. This makes hook replacement easier. Split rings are made of stainless or nickel steel, but the nickel rings do a better job of maintaining their spacing so you don't lose a hook.
Hook
Treble hooks are typically used with spinner rigs but single hooks will also work. Until recently, most hooks were nickel plated. However, red hooks have reached the market, and they're designed to encourage the feeding instincts of fish.