I’ve had a number of requests for some more information, mainly dimensions and angles. I’m sorry I haven’t answered those comments yet, but I am now.
So here’s a picture of a drawing (not to scale) showing the angles and sizes:
That should be enough to get y’all started. I suggest before you start cutting wood, that you make a complete drawing of your project, showing where all the parts will be. This will save you a lot of heartache later. You can do this on a large sheet of paper, or on the plywood you’ll be using for the back.
Here are some other questions someone sent me, along with my answers. Some of you might find them helpful:
Hi sir, I wanted to thank you for your post on making the Hammered dulcimer. I have been looking for help like that for a while. I have some questions if you would tolerate them.
First I am going to make my own dulcimer and want to make as big a dulcimer as I think I will grow into. What are the dimensions of the backboard and what were the angles?
Would you add to the top or bottom if you were going to a 19/18 dulcimer? How well did the steel rods work versus cross braces of wood? I didn’t see how big they were other than a good guess. Also did you make a groove for them or were they allowed to move freely across the braces?
How deep did you sink the tuning pins and how deep did you set the holes?
How do you locate the bridges?
The steel rods work fine, but you want to get them situated right fairly quickly. Over time they tend to get pressed into the bottom of the soundboard a little, and then they are hard to move without loosening the strings.
They float freely on the braces, but of course are held in place by string tension.
I wouldn’t use any smaller than 1/4”, with 3/8” being about perfect. The diameter of the rods you use will determine the height of the braces, so you need to be aware of this relationship as you build.
Whether you add strings to the top or bottom to expand the instrument is up to you. There’s more limitations at the high end. When the strings get really short, they are harder to tune, and don’t sound as good.
I drill the holes for the tuning pins about 1” I think. It’s not real important. You just don’t want the pins to bottom out, and you don’t want to drill through the back of the instrument. 1-1/2” should be fine.
I hammer in the pins until there’s about 1/4” of thread showing.
The treble bridge is exactly 2/5 from the left nut. The bass bridge location is not as critical. I locate mine about 1/3 from the right nut.
I hope this answers all the questions. If not, please ask them in the comments box, and I will try to answer them in a timely fashion.