Let’s dive into the making of a ronroco. Unlike the guitar, the ronroco is made from a single piece of wood. For the purpose of this tutorial, we have chosen a birch log about 90 centimeters long and with an average diameter of about 30 centimeters.

The piece has been extracted from the lower part of the trunk, where the tree has no branches and therefore does not contain knots that could hinder our work on it. In this area, it is where the wood fibers grow straighter and therefore the grain is more uniform. On the other hand, as it is the thickest and oldest part of the trunk, this piece will provide us with more compact, higher density and better quality wood than those extracted from any other part of the tree.

Birch felling should be carried out during the months in which the tree is in periods of low activity; In this way, the presence of sap will be less, so we will obtain drier wood and will largely avoid the tendency to form cracks.

Once the piece has been chosen, which we will try to be as straight and uniform as possible, we will proceed to remove the outer crust, leaving it for a few days in a place where it can be aired until we can observe that the external humidity is disappearing.

It is important that during this time we protect the piece from direct sunlight, since too much heat could cause cracks that would make it unusable. This drying period can vary depending on the time in which the tree was felled, since, as we have said, this directly influences the amount of sap that circulates through the trunk.

The next step is to split the trunk lengthwise into two halves.

For this task it would be advisable to take the piece to a sawmill. In these places there are large band saws, which greatly facilitate the work and help us obtain a straight and uniform cut.

Once we have reached this point, we will make a sketch of the instrument in which we will limit its measurements :

In the same way, we must design the plan of the instrument in profile view and as with the plan view, we will put it on paper in real size. It is convenient to have these dimensioned plans always in view to compare them with the work and at a given moment to rectify any deviation. 

Later we will capture it on paper in real size and we will use this template to mark the outline on the piece that we are going to work on.

In this way we can approximate the external measurements from consecutive recesses of the piece, which will be gradual and with drying periods between one and the other.

For the next task we will use the ax and later the pole (always using it in favor of the grain to facilitate a clean cut that does not splinter the wood).

Periodically we will monitor the state of the wood, observing if any cracks occur. We must pay special attention to the heart of the tree since having a greater amount of sap, its predisposition to crack increases considerably.

At the slightest sign of cracks appearing in the piece, we will apply a good layer of cellulosic filler to the entire affected area and let it dry before continuing to work.

Once the box is approximated externally, we will finish off the work a little with the help of a carpenter’s plane or plane, in this way we will eliminate the edges that are produced in the wood by the use of the chisel and the external appearance will be more uniform. It is then advisable to apply a layer of filler to seal cracks and preserve the piece from possible fluctuations.

Later we proceed to the hollowing of the box, to which we will mainly use the gouge. In this process we must make special mention of a peculiar tool that can also greatly facilitate our work: the curette, a special type of blade made of steel and arched, with cuts on both sides.

                                                                           

We will continue reducing the wall of the box until we get an approximate thickness of about 8 millimeters, which will be constant and uniform except for the edge where we will widen the measurement to just over a centimeter.

This widening of the wall will allow a perfect gluing with the soundboard since it increases the contact surface with it and avoids having to manufacture the typical   reinforcement pieces along the entire inner edge of the box. Once the hollowing is finished, we will proceed to the exterior polishing by means of consecutive sanding that will reduce the wall until it reaches a thickness of 5 millimeters and no more than 10 on the edge.

In this process of external finishing of the box, we can help ourselves with the rasp to lower the waist of the charango and sandpaper of various thicknesses (ever finer) to finish polishing it.

Once the box is finished, we will help ourselves with the plane and the pole to shape the handle and the shovel, work that we will conclude with consecutive sanding in which we will reduce the grain.

The next step is to make a recess of about three millimeters along the entire edge of the box.

The meaning of this is none other than to house the soundboard; in such a way that once placed on the box, its upper edge is in the same plane as the mast. For this work, we will use the milling cutter, which in addition to greatly facilitating the work, contributes to a quality finish.

Next we will build the two struts that will be glued under the lid, on both sides of the mouth; for which we will need a pine square with a side of one centimeter and about 30 long, from which we will machine the pieces as detailed in the sketch.

The struts must be housed in the box at 7 and 13 centimeters respectively from the upper edge. To do this, we will practice with a chisel the corresponding recesses where we will fit them by gluing them.

We will supervise that its upper face and the edge of the box maintain the same plane since in this way we ensure   perfect contact with the soundboard.

Finally we will apply a good layer of cellulose filler to the inside of the box.

To conclude with the body of the instrument, we are going to return to the headstock, on which we will mark the location of the pegs as well as the string grooves.

With a 12mm drill bit for wood and later with a chisel and flat rasp, we will eliminate the remaining wood and with a 10mm drill bit, we will make the holes that will give shelter to the pegs.

The inclination of the blade with respect to the upper plane of the handle will be around 10º and its thickness will be around 12mm. This last level may vary depending on the type of pegbox that we are going to use.

On the other hand, we will separate a marquetry fretwork of about 20 centimeters and two sheets of   0.6 mm plywood. of thickness.

These three pieces that we will assemble later, will form the top of the shovel.

Until this moment, we have worked on the body of the instrument; from now on we will build the remaining pieces that compose it.

The finish of the neck will be carried out once we have glued the fingerboard; at the same time we will also give a definitive shape to the heel of the sound box.

The blade finish will be the last piece machining and assembly work and will precede the tinting, varnishing and polishing processes. 

To make the fingerboard, we select a wooden ruler about 70 millimeters wide by 4 thick and about 330 long. The material, as we explained at the time, must meet a series of requirements that in our case we have found entirely in the « iron stick »; high-density wood, good stability and that lends itself to a good aesthetic finish.

From the table exposed in the section dedicated to the Measurements of the Ruler , we will calculate the distances at which we will have to place the frets on the fretboard.

To do this, we will multiply the percentages of the rope by its total measurement, which in our case is 48 centimeters. In this way we will obtain the lengths between the nut and the different frets.

You can see the graph of the rule and the distances at which we will have to make the corresponding cuts where we will later house the frets :

In a first step and with the help of a square and a pen, we will meticulously transfer these measurements to the ruler. 

To make the cuts on the fingerboard we will use a very fine section saw. The hair saws used in marquetry can be used, although we will obtain better results using a saw with a firmer blade (rib or cabinetmaker), since in this way we will achieve a uniform depth of the gutters, (in the case of hair saws usually increase at   the   ends   due to their great ductility).

 

 

We will make the cuts with the help of the square that will ensure us perpendicular and uniform sawing. Later we will outline the wedge fretboard according to the measurements shown in the sketch, finishing off the widest side in a crescent and applying fine sandpaper to its finish.

 

 

 

Once this work is finished, we will proceed to the placement of the frets, which we will insert under pressure with the help of the wooden mallet, until we achieve a perfect fit, without any of them protruding   in height from the rest.

 

 

All that remains is to cut the remaining pieces of the frets and finish them off with a metal file, concluding the finish with very fine sandpaper-based polishing.

In certain shops specializing in spare parts for musical instruments, it is possible to get frets in bars or even in rolls, although there are also guitar manufacturers that supply them cut into pieces of about seven centimeters and that they consider one more replacement for the guitar, so that it will not be very difficult for us to get hold of a game.