I’m still going to do that news post I mentioned before, but in the meantime here’s another “build” post.
There’s a little bit of a story behind this one. A couple years ago, my brother and his fiance went down to a southern state, and I knew that some of the people they were going to see were musically inclined, so I sent this HD (hammer dulcimer) down with them, so they could give it away.
Well, there were a couple things about it that in retrospect I wanted to change, and I was able to get it back from it’s owner recently. When I did, I discovered it had more problems than I had realized, so I got permission to replace it. So, here’s the old one:
Actually, it’s ashes now, but this is what it looked like just before going into the woodstove.
I salvaged the hitch and tuning pins, and I’ll be using them on the replacement. The main things that were wrong with it were, that I used Titebond 2 in assembling it, and the top was several inches too wide. Titebond 2 creeps, and the string tension on a HD can be as much as 2 tons. So the joints were slipping, and it wouldn’t hold a tune…
So, on to the project. The old one had a plywood top and back, and also baltic birch plywood braces. The new one will have a plywood back, but a cedar top, so the tone will be much better. It will have maple braces and pin blocks, and mahogany trim.
The first step is to cut the back out, and then draw the locations of the pin blocks and braces on it (it’s upside down here):
Then make the pin blocks. It’s important to use hard maple (also called rock, and sugar maple) for this. Anything softer will not grip the pins, and your instrument won’t hold a tune. I used baltic birch plywood once, and it didn’t work. We’ll leave it at that…
Osage orange would probably work too, but maple is so cheap and plentiful, and much easier to work with. Mine grew a few miles away from my home.
I cut out four pieces:
Then planed them clean and flat. Here they’ve had two holes drilled for dowels to keep them lined up when gluing, and the glue has been applied:
Then apply clamps and leave overnight:
Next a ledge is cut on what will be the inside edge of the blocks. The edges of the free floating sound board will rest on these ledges. I used the table saw for this step.
Now the pin blocks are set on the back, and the positions of the braces are marked:
Then the notches for the braces are cut, again using the table saw.
Then the top is cut at an angle, again using the table saw. In the past, I’d used the band saw, but the table saw was so much nicer for this step.
Now the pin hole pattern is taped to the angled surface, and the pin holes are marked with an awl:
Then the holes are pre-drilled with a 1/8″ drill bit. My drill press doesn’t have a tilting table, so I have to use a jig in the vise to tilt the pin blocks so the surface is horizontal:
Now the pin blocks are glued to the back. Since the top is now slanted I use the offcuts as a clamping caul, like so:
The nails are to keep the cauls from sliding “downhill”.Both of them done:
Now the braces are made. First, they’re cut to width (slightly lower than the ledge) then to length, using a miter saw:
Then a bunch of holes are drilled, so that the inside will act as one sound chamber, rather than three small ones.
Now the braces are glued in:
And some mahogany “cleats” are glued on to the outside braces, to give the trim boards something to glue to:
Then the top and bottom edges are jointed, so they will be straight and flat.Now the mahogany trim pieces are cut to length and width, then planed down to 1/2″ thick:
and then glued on:
Now the extra wood is removed with chisel and plane, and then the surfaces are sanded and prepped for spraying:
The sharp corners are cut off, to make it less painful when run into:
and the edges are all sanded round:
Then it’s vacuumed out, and gone over with a tack cloth. Then it’s time for spraying. Here’s the gun:
Here’s the victim:
I decided to leave all the woods natural, except the soundboard, which will be sprayed with black lacquer.
To be continued…