Banjos are unique among bluegrass instruments in that they consist of parts that can be disassembled, replaced, and interchanged. In fact, many banjo players experiment with their banjos, setting them up with different components in different ways to produce different qualities of sound.

Although you can see little of this component until you start taking the banjo apart, it is certainly the heart of the banjo. It can be made from everything from wood to expensive cast bronze. The banjo head is stretched tightly over the ring, and this combination determines much of what you hear. At the very low end, the rim and the ring are of one piece, either cast aluminum or some other metal or wood, and at the top end, a piece of cast bell bronze weighing around 8 pounds. The classic "pre-war" sound of the Gibson Mastertone banjos made before World War II contain some of the finest examples of this type of rim, and are much copied today. Rings are available in "flathead" form or "arch-top".

This illustration shows the cutaway view of a pretty standard 5 string bluegrass banjo. In this case, it's a flat head tone ring. The brackets pull the tension hoop down, which pulls the head downward, tightening it across the tone ring. Bolts hold the flange to the resonator. This is representative of a Gibson two piece flange "tube and plate" banjo.

The rim is the main structural component of the body of the banjo. The tone ring is seated on its top, the flange sits around its middle, and the neck attaches to it. Although rims can be made in many ways, of many different woods, most top end 5 strings have a 3 ply maple rim, formed from one long strip of maple that is formed into a 3 wrap circle using steam, then glued.

The neck attaches to the rim through the use of a dowel, or more commonly in bluegrass banjos, a set of coordinating rods. These rods connect to the rim at two points, 180 degree from one another and serve to set and stabilize the neck.

A cutaway, demonstrating the coordinator rods, tailpiece, neck connection screws, and the truss rod in the neck. The combination of these elements determine the angle and flatness of the neck.

Most 5 string banjos, at least at the high end of the spectrum, incorporate a system of coordinator rods that serve to attach the neck to the rim, as well as control, to some degree, the angle of the neck to the rim. Caution must be used when experimenting with these rods, as damage to the rim can result.

In this case, the Austin beginners deluxe model AU675. Two elements are revealed (resonator has been removed). Instead of a pair of coordinator rods, a single rod hold the neck in place. This single rod serves a similar purposes. Tighten or loosening it by small amounts will result in changes in string height, or action.

Also, this banjo is fairly typical of a single cast aluminum pot, typical of many Korean banjos. This has the advantage of providing a good solid rim while providing for a metal tone ring edge (where the pot meets the head), for considerably less money than a maple rim/bronze tone ring set up. In this case, this banjo sells for about about the same as a good bronze tone ring. Yet, it is playable, and sounds pretty good - substantial to get you going if you are beginning. 

The lower picture demonstrates how this works. The brass nut is counter threaded, meaning that if you turn it in one direction, it will draw both bolts in, while turning it out will push the rods apart (distoring the rim, changing the string height.)

The inside nut, against the rim serves to pull the neck tight to the body. This has no effect on string action.

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Basic rules for the fit of the adjusting rods: (two rod system)

1. Twisting the rods will effect the angle of the neck, but this is not how they are designed to work. There proper position is run up snug against the neck lag screws, assuring a good tight fit of the neck to the rim.
2. The adjust of the rods comes as a result of loosening and turning the nuts that lock them in place on the far side of the rim.
3. Running the nut out (clockwise) on the lower rod will force the neck upwards, raising the action.
4. Running the inner nut (inside the rim) out (clockwise) will push the top of the neck outward, lowering the action. We're talking about one or two turns of the nut, perhaps even that much. Very little movement of the rods will cause a significant response in neck angle (and rim distortion).

Necks are cut such that the lay snug against the rim with the proper angle already set to ensure proper string height. The problem with this is that bridges come in various heights. Many players prefer heigher bridges, which produce greater volume and clarity. Changing the bridge height changes the angle of the string to to the instrument, including the neck. If you're banjo neck was cut to fit to a 1/2 inch bridge, simply putting a 5/8ths or 9/16s inch bridge on will raise the action to the point that it might be unplayable. If you decide to experiment with the coordinator rods to adjust the string height, make very small changes in increments, and measure the rim to make sure you aren't distorting it out of a perfect circle. Remember, the ring won't distort with it, being made of metal, so you are also affecting the fit of the rim to the ring by adjusting the coordinating rods.

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The Truss Rod

Buried within the neck of higher end banjos, just under the fingerboard is a rod or rods joined by blocks with nuts on the end in the scalloped out area on the peghead whose purpose it is to make the neck flat. Or, more accurately, nearly flat. In order for strings to properly fret without buzzing, a slight forward bow is needed. We're talking REALLY slight, here. For the purposes of this discussion, let's just say that its purpose is to flatten the neck. The reason this is important to understand is that it is very common for new players, or folks without experience using truss rods to think that they can be used to raise or lower the action of the neck. The action of the banjo is really only properly and safely adjusted by adjusting bridge height and some minimal adjustment of the coordinator rods.

The Resonator

The resonator acts as a sort of parabolic amplifier. It takes the sound waves generated within the pot (rim and ring assembly) and bounces them outwards.

The Hoop

The hoop serves to pull down the head, tightening it against the tone ring, by using a series of brackets that communicate with it through the flange. Nuts on the brackets on the underside of the flange control this tension.

The Flange

The flange serves a few purposes. First, it is the anchor point for the brackets which pull the hoop down, tensioning the head. Second, they serve as the point of attachment for the resonator. They are perforated to allow sound to exit the pot. They also pull the tone ring tight against the rim.

The Tail Piece

This is the anchoring point for the strings. It's purpose is critical though, in that it must hold the strings down so that they form the proper angle between the bridge and the tailpiece. This angle greatly effects the sound of the banjo. Most can be adjusted downwards to increase this angle, but bridge height plays a role in this. too.

The Tuners

These serve to hold the strings taught at the peghead, and adjust the tension to create the proper note for the string. There are special "D- Tuners" that allow for special effects where a string can be tuned downwards and upwards to specific notes, as heard in songs like "Flint Hill Special".

The Bridge

This critical component of the banjo is perhaps available in the greatest number of variations of any of the banjo components. It's "where the rubber meets the road" in the banjo. All energy from the struck string is transferred through the bridge to the head, giving the banjo it's distinctive sound. Bridges can be made of many types of wood, mostly hard woods, and all shapes, heights, thicknesses and masses. Even the most expensive bridge is a relatively small expense to pay to enhance the sound of your banjo, so experiment with various bridges.

The Head

Once made of calf skin, now made of Mylar, and almost indestructible plastic that can take incredible amounts of tensioning, these are almost identical to their cousins found on drums, and really serve the same purpose: to accept the energy from the bridge or drumstick, respectively. Legend has it that when asked how tight to make the head on a banjo, Earl Scruggs is alleged to have said "I turn it down until it breaks, and then back it off a turn or two." Humorous, but serves to illustrate how tight most bluegrassers tend to run their heads. Generally speaking, the tighter the head, the brighter and louder the tone. There is also a school of thought that holds that you can tune a banjo head, just as you would a drum head. What can be said for sure is that by experimenting with the tension of the head, you can change the sound of your banjo considerably.