Banjo Maintenance

Courtesy of Jim E., Musicians Rendezvous, The Kingston Trio Place.

 

TIP 1
Let's begin with the basics: With so many adjustable parts, banjos need to be checked periodically to assure that tone and volume are not diminished by loose or ill-fitting components. You should routinely examine your banjo starting with the brackets (tension hooks).
Whatever the level of head tightness you prefer on your banjo, bracket lugs should be kept snug to assure that tension on the head remains even. Uneven tension impairs volume and tone; it can also lend to warping of the stretcher band (tension hoop). The latter has recently become more of a concern with the re-introduction of the pot metal stretcher band. Pot metal is being touted as an “improvement” over brass because, it is claimed, pot metal, unlike brass, is sonically dead and therefore does not produce any conflicting overtones. Uh huh. Manufacturers of resonator banjos employed the same rationale a number of years ago to justify a return to the (equally inferior) pot metal flange. This is a bit like Martin’s introduction and marketing of the D-35 in the late ‘60s. The D-35, with its 3-piece back, was presented as both a visual and quality ‘upgrade”, whereas it was simply a clever way for the company to economically utilize rosewood pieces that were, up to then, too small for guitar backs. Similarly, the “attributes” of pot metal parts seem to have more to do with marketing and the economics of production than with any tonal considerations. If you're buying a new banjo, you may want to inquire if the stretcher band is brass.
How do you know the correct level of head tension? Without going into the subject of head tuning, you can be reasonably assured of good volume and tone if you tighten the brackets enough to where the bridge presses down on the head between one-sixteenth and one-thirty second of an inch (with the strings tuned to concert pitch). You can measure this distance by placing a straight edge in front of the bridge, across the diameter of the head, with both ends of the straight edge resting on the rim INSIDE the tension hoop (my straight edge is a 1-foot ruler shortened by a tad more than one inch). Observe the space under the straight edge. If the space is more than one-sixteenth of an inch, tighten the brackets slightly. If it is less than one-thirty second of an inch, play the banjo for a minute or two to test its tone. If the bass seems too thin, loosen the brackets slightly until the bass response is satisfactory.
The next tip will focus on changing the head and will include an easy way to assure uniform height of the stretcher band around the entire circumference of the rim. Stay tuned;-)

TIP 2
Removing the old head on your banjo and successfully installing a new one can be a bit intimidating if you've never done it before. All that stuff about head tightness, crown height, evenness of the stretcher band, bridge placement and the like is for some beyond the line where comfort morphs into apprehension. A famous sportscaster, commenting on the complexity of professional football, once observed, "There's not enough there to mystify a nine-year-old". That assessment could also apply to banjos; any hand wringing that accompanies their disassembly usually evaporates with a minimum of experience. In this episode of NBA we'll walk through, and I hope de-mystify, the steps in changing the head on your banjo.
Among the reasons to replace a head: It is broken; it is dirty; it is too old (loss of tensile strength); you'd like to try a different type of head; because, well, you feel like it. While the first four are the most often cited, you may also safely embrace the last. Doing so will earn you neither censure nor ridicule, not from me anyway. Some may notice that I seem to have "overbuilt" this summary. You are correct. I thought a more thorough explanation would benefit those who have no experience in changing a banjo's head. Finally, while I did read through the below for clarity, it was written quickly in the little patches of free time I've had over the past couple of days. You may therefore encounter some grammatical or punctuation errors or points that seem unclear. Your indulgence is appreciated and of course I'd be happy answer any questions you may have.
Here then are the necessary steps, in recommended sequence:

1. Remove the resonator (if your banjo has one). Loosen and remove the strings. Remove the bridge.
2. Loosen the tailpiece attachment lug, remove the tailpiece and, along with the bridge, set aside.
3. Use your bracket wrench (or any wrench of appropriate size) to loosen, about a full turn at a time, the bracket lugs at the N, S, E, and W points of the rim. Loosen one, then its opposite. The objective here is to minimize stress on any one section of the tension hoop.
4. Loosen the lugs located between those you've already loosened, again working from each to its opposite.
5. When all of the pulling force on the tension hoop has been relieved, it is no longer necessary to observe the one-then-its-opposite sequence; the lugs and bracket hooks can now be removed in any order.

6. Take each of the removed hooks and, with a few turns, re-attach a lug. Place the paired hooks/lugs in a cup or similar container to keep them together and easily retrievable.
7. Lift the tension hoop off of the head. The hoop and the old head may actually come off together. No problem, simply separate them once they are off the rim.
8. If your banjo has never been disassembled, it would be a good idea at this point to inspect the bottom and inside lower edge of the hoop for small burrs or surface irregularities that could damage the new head. If you find any, examine the corresponding area of the old head for any signs of a break or puncture. It's unlikely you'll find any problems, but if you do, use a fine-tooth file to smooth things out.
9. Place the tension hoop on a flat surface and inspect it for any signs of warping. The bottom of the hoop should be perfectly flat against the surface; the sides of the hoop should be perpendicular. You're looking for "flare-out" here, a consequence of uneven bracket tension. If your tension hoop is brass (on a quality banjo nearly all of them are) it is highly unlikely that there will be any sign of a problem.
10. Once you are satisfied that the hoop is in good shape, now is the best opportunity to clean those surfaces on the tone ring and hoop that are inaccessible when the banjo is fully assembled. A cotton cloth and some metal polish (Simichrome is my fave) are in order.
11. Unless you have an unusual banjo (piccolo banjo, minstrel banjo, etc.) or an antique instrument, you will in all likelihood find that it has the standard 11-inch head. An exception would be one of the earlier Vega Pete Seeger models. The head size for one of these is 10 and 15/16 inches. If you are unsure of the size head your banjo takes, simply measure the diameter of the upper, outside edge of the tone ring (at its widest point). This measurement is more reliable than comparing the old head with the new one. I recommend the new head have a medium crown. Heads with a high crown are a problem for some banjos in that they allow the upper edge of the tension hoop to be tightened below the plane of the head.
12. Gently press the new head down over the tone ring (or over the rim if your banjo doesn't have a tone ring). Make sure the head is fully seated; its crown should be of even depth around the entire circumference. Banjo heads have long had unsightly labels on their outer surface. In recent years it seems these labels have, lamentably, grown larger and even more obtrusive. If this offends your aesthetic sense as much as it does mine, you may wish to place the label at your banjo's six o'clock position. Once the instrument is reassembled the label will be hidden, all or in part, under the tailpiece.
13. When you are satisfied that the head is correctly positioned on your newly polished tone ring (or on the rim if your banjo has no tone ring), you are ready to reinstall the (also newly polished) tension hoop. Try not to touch the hoop or tone ring with your bare fingers; you don't want to tarnish areas that will be inaccessible once the banjo is reassembled. In the years I worked on other people's banjos, I got into the habit of wearing thin cotton gloves when handling an instrument's polished surfaces. A cotton cloth works well too, but it limits your dexterity.
14. Align the tension hoop with the neck and tailpiece. You also want the hoop's hook notches to correspond to each bracket hook's attachment point. Don't worry about a precise alignment right now; we'll get it perfect when we install the hooks.
15. Before going further with the reassembly, now is a good time for a bit more housekeeping. Retrieve the hooks/lugs and, one by one, separate each lug from its hook. Inspect each for any signs of damage to the threads. If none is found, inspect the surface of both components for signs of rust or tarnish. Even on high quality instruments these parts are most often made of steel and are therefore susceptible to marring from moisture. Use 0000-grade (extra fine) steel wool to remove any surface blemishes. If any hooks or lugs need to be replaced, they are inexpensive and available from either Elderly or First Quality. Finally, lubricate each hook's threads with a drop of 3-in-One oil. Wipe away any excess oil.
16. Now we are ready for the substance of the reassembly. Install four bracket hooks - at the N, S, E, and W points on the rim - and attach their lugs a little less than finger tight. With your banjo placed backside down on a flat surface, observe the alignment of the hooks. The shaft of each should be exactly perpendicular to the upper edge of the hoop and to the bottom edge of the rim. If not, rotate the hoop slightly until everything looks good. The hoop's neck notch should be centered on the end of the fingerboard and the space for the tailpiece should be centered over the tailpiece attachment point.
17. Once you are satisfied with the position of the hoop, install the rest of the bracket hooks and lugs. Make each lug slightly less than finger tight. Again check the alignment; the hooks should be exactly perpendicular. If they are not, gently rotate the hoop until they are.
18. Here is where you need to fashion a "tool" to better assure a uniform tightening of the lugs while minimizing the chance of placing undue stress on any one segment of the hoop. Get a small piece of thick paper - a standard business card or a 3"x5" index card, cut in half, is perfect - and on one edge of the blank side, pencil a few lines, each 1/8" apart. This will serve as your gauge for determining uniform (level) height of the tension hoop.
19. With your bracket wrench, begin to tighten each of the lugs in the one-then-its-opposite sequence. Do this slowly; tighten each lug about one-quarter to one-half turn at a time. While doing so, strive to keep the tension hoop level. Here is where your newly fashioned tool will help. Keep the edge of the card flat on the head and keep the top of the stretcher band aligned with the nearest pencil mark as you continue to tighten the bracket nuts. Use the gauge to measure at various points on the head throughout the tightening process. Here is a pic to illustrate:

20. How much to tighten? Banjo heads are made of mylar, and a new head will continue stretching over the course of several days to several weeks. For now, bring the head's tightness up to where it does not give under firm finger pressure.
21. When the new head installation is complete, reattach the tailpiece and install new strings. Tune the banjo to concert pitch and test its sound. Tighten the head incrementally over the next several hours until you are satisfied with the tone. As discussed previously in TIP 1, the final tightness of the head should be such that the bridge creates about a 1/16" depression where it rests on the head.
We're done! You may want to adjourn to comfortable chair to admire your work (celebratory libation optional). You saved about $150 (the amount your local music store would have charged to complete all of the above steps) and you have gained some practical knowledge of banjo maintenance. Again, feel free to ask questions or for clarification about any step(s) in this process.

 

May 15, 2007