Installing them can be tricky, but you can do it with the right tools. The first thing to know is that you must drill holes for the spikes rather than simply drive them into the fingerboard. The types of wood used in fingerboards are generally so dense that driving even a tiny spike into them causes the wood to move laterally, producing anything from a split or crack, to a bulge in the binding.

We sell spikes one our site, or you can find them at a local hobby shop. The problem with buying them at a hobby shop is that you will have to buy at least 100 in a package, or as many as 500, but a package only sells for a few dollars). The spike is a perfect replica of it's life-size counterpart, and looks like a nail with a flattened hook for a head. This hook it what we will use to grab the 5th string and force it to be fretted at that fret. One note if purchasing from a hobby shop: You may ask for HO gauge rail spikes and be met with the question "What code?" In model railroading, "code" means height, shape and width of rail. 100 code is a smaller, more "to scale" code than 80 code. Ask for code 80, or mediums, if the spikes simply come small, medium, large.

Your local hardware store will sell a small drill that consists of a handle that looks somewhat like an Exacto knife, and contains a bunch of tiny bits in the handle, along with a small chuck to hold the bits. These bits are too small to be marked (plus you couldn't read the markings if they were) so if you have access to a micrometer, what you're looking for is a bit just slightly smaller than the shaft of the spike.

In the lower part of the drawing, you see two paths that the string takes. One is uncapoed (red slash) and the other is an imaginary path were the string capoed under all installed spikes. This is to illustrate one technique used in which spikes are installed at staggered positions along the line of the string so as to minimize the chance of string buzz. This distorts the pitch of the string slightly, and also takes the string ever so slightly out of the normal path, which can make for slightly different fingering, but it is an effective way to avoid buzzes.

The alternate method - putting all the spikes in a line - requires that each spike be installed to the absolute correct height to avoid buzzing.

Also, some luthiers will install the spikes with the flanges all pointing "up" the board. That is, upward as you hold the banjo. If you are a bluegrass 3 finger style player, you will almost always be striking this string with a down stroke, and having the flange point towards the stroke prevents it from jumping out from under the flange. Having said this, it takes a pretty good whack to do this, even when the flange is pointing downwards. Clawhammer players tend to experience this more than Scruggs style players as the string vibrates in much wider, longer waves when struck with a thumb or the back of a finger than with a sharp pick.

Installing the spikes

1. First, detune the 5th string enough that it can easily be held out of the way with your free thumb during this process. You may want to use a piece of masking tape to hold it out of the way.
2. Using your drill, select a bit slightly smaller than the width of the spike. Start twisting the drill clockwise on a spot under the string (or in an alternate path as above) being careful not to bend the bit which will break off easily, creating a real nightmare, if it breaks flush with the board.
3. Watching the threads on the bit, continue drilling until the depth of the spike is achieved.
4. Next, using a needle nose pliers (the finer tipped, the better), hold the spike just under the flange pointing the flange in the direction you choose based on the discussion above, and gently tap the point into the hole until it is about half way embedded. At this point, the spike is not so far down that you can't turn it a little, or even remove it if you have made a mistake.
5. Now, using an automotive feeler gauge, select the .020" blade and place it under the flange of the spike head. Gently tap the spike down until it just grabs the blade. If you have to struggle to remove the blade, you have hit too hard or too many times, and the head may have to be worked back out a bit with the needle nose pliers. This is very difficult to do without scarring the fingerboard, so go easy and slow, using lots of small blows rather than a few heavier blows.
6. Bring the string up to pitch. Place the string under the flange firmly, so that it is completely snug against the shaft of the spike. Strike it with a pick and see if you get a buzz. If this is your first spike, you shouldn't, at least in theory, get a buzz. All you have done is fretted the 5th string. If it buzzes now, it probably buzzed before. Where buzzing comes into play is when you are installing your second or third spike. Typically, spike are installed at the 7th fret, 9th fret, and 10th. If you are installing the spike at the 9th fret, go back and capo the string at the 7th to see if it will buzz. If it does, this means that the spike in the 9th is not deep enough - lower then the 8th and 9th fret. If you are installing the 10th, go back and fret at the 9th to check for a buzz. Continue to tap the spikes to achieve the right height, always using the feeler gauge. (If you don't use the gauge, it is possible to drive the spike flush with the board at which point it is not only unusable as a capo, but nearly impossible to remove or adjust without breaking the spike or scarring the board.

How many spikes you use, and where you put them are completely up to you. The nice thing about using this method is that it is easily reversed. You can remove the spike and stick the tip of a toothpick firmly into the hole, cut it flush with an Exacto knife, or some other flush cut tool, and simply dab the exposed wood with a marker of the color of your fingerboard.

A last word. These little spike heads can be quite sharp when passing your thumb or finger over them. You might want to take a small file and round off the head just a little. This will also aid in some buzzing situations.

If you have questions or problems, please feel free to send them to jim@pensonstringwerks.com