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Repairing sticky nyckelharpa keys

by Bart Brashers

This is a somewhat common problem with nyckelharpas, especially as they get older. The key just won’t come back out after you’ve pressed it, and its tangent either keeps pressing against the string (producing the wrong note) or buzzes against the string. You have to stop and pull it back “out” manually. There are essentially two ways of dealing with it: lubrication or sanding. Both involve removal of the key from the keybox, but that’s not nearly as hard as it looks. Lubrication will help in marginal cases, but often that’s not enough.

First you need to get the sticky key out of the keybox. If the key in question is in the first (top) row, easy, and if it’s above the G on the first string it’s even easier. Usually, overcoming the fear involved is much harder to do than the actual repair itself.

Look at the top of the keybox: there is a thin strip of wood on the right edge (just the other side of the tangents from the A-string) that holds the keys in their slots, call it the “comb-lid”. The keybox is just 3 layers of “combs” (wood with slots) on top of each other, with the comb-lid holding the top-most layer of keys in place.

Put your nyckelharpa on your work surface (I use my kitchen table). If you want, you can use a cloth or carpet remnant under it to protect the bottom from scratches. In this article, when I say “up” I mean perpendicular to the table (and the harpa top and bottom). When I say “in” and “out” I mean in the directions the key travels in normal use: “in” as in `press the key in, toward the string’.

Take a small screwdriver and remove the 2 or 3 screws that hold the comb-lid in place. Often, the screws are not all the same size, so make a note of which one goes where, and put the comb-lid aside. You don’t need to remove the comb-lid-like piece of wood that’s on the other end of the keys (under the low C-string) since the keys can just be pulled out from the comb on that end.

If the sticky key is on the first string and higher than a “G” (i.e. doesn’t have a slot in it for the 2nd or 3rd row tangents to protrude up through) then you should be able to simply pull up on the key until the “shoulder” of the key clears its slot, then slide it out from under the strings. The other end of the key (the non-finger pressing end) will simply get pulled out from its slot. You may have to loosen some of the strings to be able to lift the key up far enough to clear the comb.

Exploded view of a keybox (only two layers shown)

Exploded view of a keybox (only two layers shown).
Tangents and holes in key for lower-row tangents not shown
View this as a PDF.

All the other keys require that you loosen all the strings. Not just a little, but a whole lot. You should be able to lift a string up at least an inch above its normal position, so a key can clear the tangents the protrude up through it. It’s either loosen your strings, or remove the tangents from the keys in the lower rows.

Of course, if you loosen your strings, there will be no tension on the bridge, so it will be free to come off, and the sound post may be able to move. So before you start, measure the length of your A-string and your low C-string — they should be 40.0 cm long, but if they’re not, write down the actual string lengths so you can put the bridge back in the same place when you’re done. Make sure you remember which side of the bridge face the keybox, too. Look in through the f-hole at the sound post, and try to remember where it is in relation to the foot of the bridge. You can even try to measure its position by using heavy paper with a notch (for the sound pin) inserted through the f-hole until the notch touches the pin, then tracing the edge of the f-hole on the paper. Now loosen the strings. I’ve even sometimes removed the tailpiece to get the strings completely out of the way without having to unwind all the string from the tuning mechanisms.

The rest of the first row of keys can be removed by lifting them up far enough to clear not only the comb, but far enough to clear the tangent from the 2nd and 3rd rows as well. That’s why the strings have to be so loose — they would prevent you from lifting the key up far enough to clear the tangents from the lower-row keys. Lift a key up enough to just clear the comb, then move it forward (out) so that the other end is pulled from its comb, then lift it up to clear the tangents sticking up through its slot.

If the sticky key is on the first row, you only have to remove that key, but if you have sticky keys in the 2nd or 3rd row, you’ll have to remove ALL the first row of keys. Remove them one by one, placing them carefully to the side. They should be numbered on the bottom, near where the tangent is attached. If not, number them yourself, starting with 1 for the Bb key, 2 for the B, 3 for the C, etc. Once you’ve removed all the 1st-row keys, you’ll notice that the 1st-row comb can be removed by taking out a few screws that hold it to the 2nd-row comb. This frees you up to remove the 2-row keys in the same manner as the 1st-row keys came out. Keep in mind, you don’t have to remove the non-finger end combs — just pull the keys out of their slots. Make sure the 2nd row keys are numbered as well. Of course, if you don’t have any sticky keys on the 3rd row, you only have to remove the sticky 2nd-row key, not all of them.

The 3rd-row keys are a bit different. There’s not enough wood below to use screws to hold the 3rd-row comb in place. (The screws are actually screwed in from below, through the relatively thin “bottom plate”, which is then itself screwed to the neck. You don’t want to remove the whole keybox if you can help it, so leave the bottom plate in place). Many nyckelharpas have small holes drilled into each key just inside of the comb, into which a small (1 mm) dowel or other plug is placed. The plug protrudes up far enough to keep the key from sliding out, but not far enough to touch the 2nd-row key above it. Remove the plug with pliers, but save it. You’ll also have to remove the tangent to be able to slide the key all the way out from the keybox, or you can simply pull the key far enough out to expose the part that needs work (the key-comb juncture) and work on it in place. Removing the tangent can be risky, especially if it’s a humid day and the wood has swelled. It’s easy to break a tangent, often splitting it lengthwise under the torsional stress. Try first with your fingers to twist the tangent out of its hole. If/when it doesn’t budge, use flat jaw (no teeth) pliers, and grasp the tangent as close to the base a possible (not near the top where the torque you are applying can torsionally rip the wood apart). Twist gently, pulling as you go, and work the tangent out of its hole in the key.

Graphite works well as a lubricant. The idea is to apply some graphite to the side of the key where it touches the keybox, and to the slot that the key rides in. You can use a normal soft-lead pencil, and just “color in” that area. Put on a lot, as it certainly won’t hurt, and will keep you from having to do at again for many years. Blow away any excess with a puff of breath.

However, often just lubricating the keys is not enough. You’ll have to remove some of the wood in either the key or the inside of the slot. DO NOT USE SANDPAPER! It is critical that both surfaces be smooth and flat, to form a solid junction. The better the connection between the key and the slot, the clearer that note will be. It is nearly impossible to hold sandpaper flat — you’ll end up taking more wood near the edges, and creating a convex surface rather than a flat one. Use a file. I have a very nice small fine-toothed file that I keep in my nyckelharpa case.

Inspect both the key and the slot first, looking for burrs or other irregularities, which are almost always the cause of a sticky key. look also at the bottom and top surfaces of the key, not just the sides, and the bottom and top of the slot, looking for a reason the key is sticking. File away only a little bit at a time, and work the file only one way (pushing or pulling, but not both). You don’t have to take very much at all, really. The key should slide easily in the slot, but not be so loose that it rattles excessively. Take a little, then replace the key and try it out, pushing it back and forth with your fingers, or pressing the key and letting gravity pull it back. Keep in mind that the actual distance the key travels when your nyckelharpa is all in one piece is very small!

Lubricate you keys as you put them back with pencil.

Although it sounds like the most dreaded line in a car-repair manual, assembly is the reverse of the above. Put the 3rd-row key(s) back in place, inserting the little plugs as you go. If you lose one or if it was destroyed trying to get it out, whittle another. Then screw on the 2nd-row comb. Make sure you don’t screw it down so tight that it pinches the 3rd-row keys and they can’t move. Put the 2nd-row keys back, and the then screw the 1st-row comb in place, making sure the 2nd-row keys can still move freely. Then put the 1st-row keys back in place, and the comb-lid.

Before you start to tighten your strings again, inspect the sound post. If it has fallen over and is rattling around in there, or has migrated, you’ll have to move it back to its original position. This can be hard to do, and violin makers use special tools (available in catalogs, I might add) but do the best you can with the tools you have, or go to a violin shop and ask for help. Tighten your strings evenly, each one a bit at a time, making sure your bridge is in the right place (string length 40.0 cm). Note that as you tighten, the strings tend to pull the top of the bridge toward the keybox, making the bridge lean. Make sure it sits up straight, with both feet planted firmly on the top of the body (make sure there are no “cracks” between the foot and the top). If the feet don’t make full contact with the top, you won’t get full transmittance of the sound from the strings into the body, and your nyckelharpa won’t sound as good. It helps to tune the nyckelharpa once an hour for a few hours before playing, as your strings will be stretching again under the tension and won’t stay in tune.

Then play. Often. A lot. Have fun. E-mail me if you have problems.