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A more-or-less copy of a Martin OM

Posted: Thu Aug 14, 2014 1:56 pm
by MaineGeezer
IMG_2940.JPG
As I mentioned in my new member's intro, luthier Carter Ruff of Subterranean Music Works agreed to teach me to build a guitar. We started with a mountain dulcimer as a warm-up project, and his suggestions and instructions were of great help. I'm now starting on a guitar, and I'll try to give a running account of what happens.

Although my initial plan was to build a copy of an old Bruno parlor guitar I have, I changed my mind and decided to build an OM copy. This was motivated in part by: A) I already have a Bruno-sized guitar, the Bruno itself; B) Carter has an OM body mold, saving the work of making a body mold. I made one for the dulcimer, that proved I could do it, I don't need to do it again.

Choice of wood. Originally I had the idea of building a guitar entirely of state of Maine wood. This didn't quite happen. What I ended up with is:
1. Back, sides, and neck will be black walnut from New Hampshire.
2. The top will be red spruce from Maine.
3. The center strip in the neck will be hophornbeam from Maine.
4. The bridge, fingerboard, and head cap will be dogwood from somewhere, unknown.

It's going to have a pocket-slotted peghead. I like the appearance, and it is uncommon.

The neck will have a diamond volute at the neck-headstock meeting point. Just for appearance, again.

I made some dogwood bridge pins....

Re: A more-or-less copy of a Martin OM

Posted: Thu Aug 14, 2014 7:22 pm
by johnnparchem
A running account with photos, I hope. I would love to follow your progress the dulcimer looks great. With reference to your grandmothers description, I am not so sure that barn carpenters turn their own bridge pins.

Re: A more-or-less copy of a Martin OM

Posted: Sat Aug 16, 2014 10:37 pm
by MaineGeezer
A generous fellow gave me a dogwood log a couple of months ago that he had had in his garage for 35 years. Well seasoned! Unfortunately, it has a lot of checking throughout, so I can't get anything very big out of it. I had hoped for a fingerboard, but there is no way. I have managed a bookmatched headstock cap, however. I whacked off about a foot of log and proceeded to attempt to quartersaw it on my table saw. I've got quite a small saw, so I couldn't get very wide slices. Most of what I got was pretty boring in appearance, but I did get a couple that have striking medullary rays. I jointed and glued them together as a bookmatched pair, with an eye to having the result be the headstock cap. You can see the outline of the headstock traced onto the wood in the picture.

Something better may come along, but for the moment this is what I'll use.

I was able to locate a piece of dogwood suitable for a fingerboard at Vancouver Island Exotic Hardwoods. The piece was thick enough to resaw. When we did, the result was as shown in the picture. Quite spectacular. Carter suggested a bookmatched fingerboard, which would be gorgeous, but there would be so much waste I can't bring myself to do it. A fingerboard from just half of it will be nice too.

Headstock cap located on headstock with a couple of pins

Posted: Sun Aug 17, 2014 5:09 pm
by MaineGeezer
The cap is down to 0.1" thickness. The end that butts against the nut is cut square and beveled to match the headstock angle. Two dowel pins locate its position for when I get up the nerve to glue it in place.

I think that dogwood grain is amazing.

Gluing the head cap

Posted: Wed Aug 20, 2014 12:43 pm
by MaineGeezer
One can never have too many clamps....

I'll go drive out the dowel pins I used to locate the cap with in a few minutes, so they don't get glued in place.

Machining cap+headstock down to its final 3/4" thickness

Posted: Wed Aug 20, 2014 10:36 pm
by MaineGeezer
I took up metalworking as a hobby about 30 years ago. Among other things, that hobby resulted in me having a milling machine in the basement. It's useful for guitar buiiding too!

It's going to be a slotted headstock, hence the need for 3/4" thickness.

Re: Machining cap+headstock down to its final 3/4" thickness

Posted: Wed Aug 20, 2014 11:04 pm
by johnnparchem
MaineGeezer wrote:I took up metalworking as a hobby about 30 years ago. Among other things, that hobby resulted in me having a milling machine in the basement. It's useful for guitar buiiding too!

It's going to be a slotted headstock, hence the need for 3/4" thickness.
That is very cool? Do you build metal jigs with the milling machine?

Re: A more-or-less copy of a Martin OM

Posted: Wed Aug 20, 2014 11:30 pm
by MaineGeezer
I'll attempt to build almost anything, with varying degrees of success. At one point I was building model stationary steam engines.

For the guitar project, I'll use the milling machine to drill the holes for the tuners and to cut the slots, except they are going to be pockets, not slots. I rigged up a horizontal spindle so I can run a slitting saw to cut the fret slots. The digital readout I have is accurate to +/- 0.0002", which ought to be close enough. I've used it to make a couple of guitar bridges.

Re: A more-or-less copy of a Martin OM

Posted: Thu Aug 21, 2014 6:42 am
by tippie53
Love the Mill I use mine a lot also.
thanks for posting

Cut string pockets;Installing tuners; the volute didn't work

Posted: Fri Aug 22, 2014 10:44 am
by MaineGeezer
The volute at the back of the neck was a failure. I didn't allow enough wood, my carving skill wasn't up to the task, and in the process I took a divot out of the back of the headstock that I needed to repair. The repair is fairly inconspicuous, but I think I may put a veneer on the back of the headstock to cover the blunder.

The string pockets came out well, thanks to the milling machine and a 9/16" ball nose end mill. I hope there is enough clearance under the tuning pegs for the strings; I think there is.

I've installed the tuners on one side. Next step is to drill the other side and install those tuners so the screw holes are correct....then take them off while the rest of the neck work happens. This is probably not the most efficient way to go about it, but my curiosity about the appearance compels me to install the tuners to see how they look.

I haven't shaped the end of the headstock yet, leaving extra wood so the final shape doesn't run the risk of getting damaged.

Next big step is to profile the rest of the neck.