Knotline

Adventures in Luthiery

 

David Freeman - Timeless Instruments

The Mandolin Cafe

Island Mountain Arts

Wells Forest Community

The Mandolin family

In February of 2001, I traveled to Wells, east of Quesnel and just outside Barkerville. The Wells Forest Community and Island Mountain Arts gallery presented an instrument making course with David Freeman of Timeless Instruments. In the ten days of the course, I learned the basics of luthiery and built my own mandola.

The first question is "What's a mandola?" It's a stringed instrument in the mandolin family. A mandolin is tuned in fifths, to the same scale as a violin. That is, G-D-A-E. Each string is a half octave higher or lower than the next. Also, each string is doubled - there are two strings, played as one, tuned to the same tone. (Some instruments in this family tune the pairs to different tones. The cittern and bouzouki, for example.)

A mandola is tuned a half octave lower than a mandolin. It's tuning is C-G-D-A, the same as a viola. In size, it's slightly larger and longer. For a mandolin, the scale length is 13 7/8". The mandola scale is 15 7/8" or about 15% longer. The neck and body dimensions are equivalently larger.

(I have to note here that the given scale lengths are not rigid figures. They can be altered slightly to meet other factors or needs.)

For various reasons, I chose a scale length of 21 3/4". (Big guy, big hands, big instrument... ) The strings readily available are designed with a 15 7/8" scale in mind, so I've had to tune to a lower tension than normally would be used for a mandola. Instead of the C-G-D-A, I'm using an octave mandolin tuning of G-D-A-E. Same as a mandolin, but a full octave lower.

It's not what I intended, but I'm really pleased with the outcome. This tuning sounds even better than I'd imagined the mandola would!

 

The heel block - This block forms half of the joint between the neck and body. The style of joint used in the course was a simple mortise and tenon. Other styles include dovetails and bolt-on joints. Note the center line drawn the length of the blank. Almost all measurements are taken from the centerline, instead of one edge, to ensure accurate and symmetric results.

The neck material shown here is mahogany, however some other participants used walnut.

neck and ears

Headstock raw - The headstock has been cut from the neck blank and re-glued in its angled position. Extensions (ears) have been glued to the outside edges to build width.

Shaped headstock

Shaped headstock - The headstock has been profiled to its final shape and a veneer of rosewood has been applied. Note the steel reinforcing bar set into the neck. Guitars often have an adjustable reinforcement, called a truss rod, to control neck bending. In this case, the bar merely adds rigidity and prevents excessive bending from the tension of tuned strings.

Top with sound hole inlay - The rosette strengthens the edge of the sound hole. It's also a nice visual touch. Shown here is the rosette inset, glued and levelled with the scraper. Also shown is a prepared rosette and a scraper in a hand made holder.

The top, or soundboard, is sitka spruce. The profile of the instrument has been traced onto the surface. The sound hole will be cut with a small router in a later step.

It's not easily visible in this picture, but the top is made of two book matched pieces of spruce joined on the axis of the instrument. This ensures equal tone response from both sides of the soundboard as well as a visual match of the grain pattern.

bracing

Bracing - Internal bracing adds strength to the top and back. It may also add shape, as in the case of an arch top or a bowed back. Top bracing also affects the tone response of the soundboard. By balancing the stiffness and the mass of the bracing, the bass and treble response of the top can be optimised.

The filet running the length of the back isn't bracing, but a reinforcement of the glue joint where the two book matched walnut pieces were glued.

Bow press

Bow press - The maple rods bent in the press provide precisely located clamping. This allows even and specific pressure when gluing odd shaped work. When gluing the top or back to the sides, it allows the luthier to avoid pressure on sensitive or weak areas.

The mustard bottle isn't a relic of lunch. It's being used as a glue applicator.

Bent sides and kerf

Sides and kerfing - The sides (walnut) have been bent to their approximate shape. The kerfing, which adds strength to the joint between the sides and the top and back, has also been bent.

In this case, as is most often so, continuous kerfing is used. For some styles of instruments, individual kerfing blocks, called fingers, are used.

Neck and butt blocks

Gluing the neck and butt blocks - These two blocks provide support at the top and bottom of the body. The butt block supports the point where the two sides join as well as supporting the tailpiece and strap pin. The neck block supports the neck and has to transfer the stress of the string tension to the body. It also helps shape the sides as they curve in to meet the neck.

Here, also, you can see the form that holds the sides in their final form.

Gluing the kerfing - The kerfing is held in place with hi-tech, super precise clamps as it's glued in place.

body, neck and fingerboard

Body, neck and fingerboard - The major parts are ready for assembly. The soundboard is attached to the sides and the neck joint mortise and tenon is prepared.

The neck joint sets the angle between the neck and body. This rake angle is critical because it controls, with the nut and bridge, the height of the strings above the frets. This height, the "string action", determines a lot of the playability of an instrument. Incorrectly set, it will result in buzzing or heavy fingering. On this instrument, a rake of 1.5 degrees was used.

This picture isn't reversed. The writing inside the body is written in reverse so it can be read with an inspection mirror.

Gluing up - Once the neck is attached, the fingerboard is glued down. Note the channel down the center of the caul. Directing the clamping pressure to the edges of the fingerboard ensures there will be no gaps between the neck and fingerboard.

(This is Bill's instrument, not mine. Note the scroll cut on the headstock. I was concentrating on the work and forgot to get a picture as I clamped.)

neck trimming

Trimming the fingerboard - Once the fingerboard is glued to the neck, it has to be trimmed flush to the neck. The bulk of the waste wood is trimmed off before gluing, but the final dressing is done by hand with a sharp chisel. Care must be taken when trimming the fingerboard on the body not to damage the soundboard surface.

ready for strings

Ready to be strung - The frets have been installed, the tuning machines are mounted, the mother of pearl dots are set in the fingerboard. All that remains is to mount the tailpiece and then it's time to start working on the strings.

Before the strings can be mounted, the nut and bridge have to be prepared. Both pieces have to be grooved to hold the strings in their correct spacing, and heights must be set to give good action.

Strung at home - The instrument is still "in the white" at this point. Finishing will involve removing the strings and bridge and applying tung oil. (There are other types of oil that could be used, but polymerised tung is what I have at hand.) Before and after each application of oil, the wood will be sanded with MicroMesh to a fine finish.

 

 


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Last updated 9 April 2001