An Interesting Dulcimer Repair

A problematic dulcimer back.

A friend owns a dulcimer she loves and it developed multiple cracks in the back and soundboard. The cracks in the soundboard were typical cracks one sees in a quarter sawn spruce soundboard and were easy to fix.

The back was another story.

The back is made of poplar. Poplar is one of the traditional woods for dulcimers and works well but on this dulcimer the poplar is close to paper-thin and flat sawn.

Wood that is flat sawn is much less stable than wood that is quarter sawn. The wood was so thin that usual methods of crack repair were difficult if not impossible. The back of the dulcimer had no bracing and little structural integrity.

My first thought was to simply make a new back but my friend loves the sound of this dulcimer and replacing the back would most likely cause it to change.

Instead of replacing it I decided to fix the cracks as best I could and add a Galax back. The Galax back will provide structural integrity and should the repaired cracks in the original back open they will not cause a problem.

Repairing a cracked dulcimer back.

Another part of this adventure was fitting the Galax back to a dulcimer with sides that were not always square, perpendicular, and flat. I don’t know if the dulcimer was made this way or if these problems developed over time. Either way, fitting and trimming the support blocks along the edges of the back was not easy. I decided to choose functionality over beauty and just get the job done.

When fitting a new back or Galax back to an existing dulcimer one has to keep in mind that forcing the dulcimer to conform to a flat back might flatten intentional or unintentional differences in height along the sides and result in distorting the soundboard and fretboard.  To avoid this I fit the Galax back to the dulcimer and let it follow any irregularities so the existing geometry of the dulcimer remains unchanged.

Galax back added to a dulcimer.

I generally only do repairs on my own work and refer requests for repairs on other maker’s dulcimers to the maker or repair shops I know and trust. This was for a dear friend so I was happy to do it.

What’s On The Bench – 11/20/2017

Slotting an ebony dulcimer fingerboard.

On my calendar was recovery from back surgery this past week but there was a change of plans; a dental issue came up and surgery was postponed. Instead I am taking antibiotics and will have minor dental surgery in a week or so. The back surgery will probably be within a month or so after that.

Let it not be said that I don’t know how to have a good time!

I’m a firm believer that what is happening is happening and what is not happening is not happening so I am rolling with it.

In the meantime I am up to my usual tricks and getting some work done in the shop.

In the photograph above is a simple setup for cutting fret slots. The miter box is made from scraps of MDF and the depth stop on the saw is a strip of wood held in place with three colorful spring clamps.  The wooden cam clamps hold the miter box to the work-board and holds the fretboard in place while sawing.

This  low-tech setup works remarkably well.

I have templates for fret patterns I commonly use. The templates eliminate calculating and measuring out the fret positions.

This fingerboard is for a custom chromatic dulcimer with a scale length I have not used before; 743 centimeters! That is a very long string length but is what the person who will be playing this dulcimer prefers.

Since I didn’t have a template for this scale length I had to calculate the fret positions and lay them out on the fingerboard. Fortunately, there is software that does the math. In the 1970’s I had to spend a long time with a calculator to work out fret positions. The constant often used to calculate an equal tempered fretboard, 17.81715385, is still permanently installed in my memory.

I laid out the fret positions using a very accurate ruler, machinist’s square, sharp knife, and patience. I triple checked the measurements before sawing the slots.

Sawing the slots with the miter box was the fun part.