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Martin 1-18, 1918
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Author:  George Thomas [ Tue Jun 16, 2009 5:43 pm ]
Post subject:  Martin 1-18, 1918
Hi All:

I am wondering if anyone has built from this 1918 Martin 1-18 plan. The notes on the plan by Ted Davis describe it as lightly built for gut strings. LMI lists it with their steel string plans. As near as I can tell the plan has elements of both. I have looked inside two Martins (1895, and 1925) apparently built for gut strings. They both were X braced and had pin bridges but if I recall correctly, the braces were lighter than the braces on the Davis plan (1/4x 1/2 before scalloping). Top and back thicknesses seem a little thicker than one might use for gut or nylon. The top in the guitar copied for this plan was Adi.
Any suggestions? Thanks.
Author:  David Newton [ Tue Jun 16, 2009 8:53 pm ]
Post subject:  Re: Martin 1-18, 1918
Hi George.
With considerations to the thickness of the top, it's stiffness, and the stiffness of the bracing, 1/4" x 1/2" would be fine for a steel string guitar.
Author:  meddlingfool [ Wed Jun 17, 2009 11:49 am ]
Post subject:  Re: Martin 1-18, 1918
I've built two with that plan, and loved them both. The first was sitka/mahogany, and had slight issues of some notes playing louder than the others up and down the neck. The customer has restrung it with silk&steels, and she very much loves it. The second, adi/blackwood is one of the best, if not the best guitar I've made. I left the bracing dimensions exactly as on the prints, and only varied the plate thicknesses to suit the actual pieces. Also, I would personally recommend making the fingerboard just a bit thicker. I put purfling on the bottom edge of the FB binding, and when I radiused the FB it was pretty dicey, I would definitely have liked some more wiggle room, but it worked out all right in the end. Anyway, I think it's a great design, certainly a great place to start from and adjust to taste. I can't hardly wait to make another!
Cheers
Author:  George Thomas [ Wed Jun 17, 2009 10:10 pm ]
Post subject:  Re: Martin 1-18, 1918
This was interesting. 200 views and 2 responses. I guess the Martin 1 plan is not all that popular. But then Martin no longer makes the 1 because no one was buying.

Fortunately the 2 responses were quite helpful so I got the help I needed. Thanks very much.
Author:  David Newton [ Wed Jun 17, 2009 11:22 pm ]
Post subject:  Re: Martin 1-18, 1918
George.
It's pretty goofy. Players usually want big guitars. Builders love little guitars. So... you end up building little guitars and have to almost give them away. I can't stay away from them, I want to make a 2 size guitar that's good for bluegrass!
Author:  George Thomas [ Thu Jun 18, 2009 12:06 am ]
Post subject:  Re: Martin 1-18, 1918
Attachment:
guitars.JPG


David:

I would love to hear the 2 when you finish it.

Meddlingfool:

Here is a pic with my small body hybrid or crossover in comparison to my standard classical and a Taylor GA4.
Author:  jackwilliams [ Thu Jun 18, 2009 10:47 am ]
Post subject:  Re: Martin 1-18, 1918
I built my first 1-18 in 1997 from Ted's plans and from spruce I got from him... adirondack/mahogany.. it was also my first small guitar build. I overbuilt the top somewhat and as a consequence it is not as loud as I would have hoped for;
I have built three or four others of the same size and with lighter bracing and thinner top and have been very pleased with them. I love small bodied 12 fret slot head guitars!
Author:  Kevin Mason [ Fri Jun 19, 2009 10:41 am ]
Post subject:  Re: Martin 1-18, 1918
Someone posted the same question over on the MIMF a while back, so you will find a bit more information in that thread. I've made two guitars based on the Martin 1-18 1918 plans. I didn't try to copy it exactly--basically used the body shape and general bracing pattern but making the string scale longer (I believe the plan is a short scale). I love the resulting sound. I find it full, balanced, great resonance, really responds well to finger style playing (especially blues/jazz), and also light folky kind of flat picking. I think the size 1 is a really successful instrument. People just seem to think that bigger is better. Their loss.
Author:  George Thomas [ Fri Jun 19, 2009 2:46 pm ]
Post subject:  Re: Martin 1-18, 1918
Thanks for the responses. Now I am excited about getting this guitar done. I play fingerstyle so a little light on the bracing seems to be the way to go.
Author:  tfchristie [ Tue Dec 09, 2025 7:52 am ]
Post subject:  Re: Martin 1-18, 1918
Greetings,
I am gearing up for a build of this plan. One question already answered: The fingerboard seems awfully thin. It sounds like the bracing and top are suitable for steel. Right now my big question is the back arch. From the side profile and what I have read, it doesn't seem like a radius dish situation. It sounds like old examples have maybe a constant curvature longitudinally, but maybe a couple of radii with a "kink" at the waist. (long thread on umgf) I am wondering what those of you who have built this have done. Like meddlingfool, it seems everyone who builds this loves it, so I am pretty excited about it. I would be interested in construction method details. For a dish, radius and peak location would seem to cover it. This is only my second build. I did not use a dish on my first, but used a sanding beam -- flat for the top side, and with a wedge for the back. It seems like this would produce the lateral curvature that varies with the width across the bouts or waist as reported in that umgf thread. I just reviewed Cumpiano's approach and it is somewhat different using a larger sanding board and the rims themselves providing the "wedge" so to speak. He doesn't say much about the lateral arching other than it is caused by the sides of the rims. (I couldn't find specific construction guidance on sanding that aspect) His method seems like it would produce the longitudinal kink, but a more constant lateral curvature. Any thoughts or insights? ps. I am adding to this thread rather than starting a new one because my question is really the same as that of the OP, I hope that is OK. I am new here, so I am not clear on the "the way" here. ;)
Author:  Darrel Friesen [ Tue Dec 09, 2025 2:47 pm ]
Post subject:  Re: Martin 1-18, 1918
I built one 15 years ago or so completely out of pine other than fretboard, bridge, binding and headplate. I beefed up the bracing a little and use extra light steel strings. Still plays and sounds great. I keep meaning to build another using nicer woods.
Author:  meddlingfool [ Tue Dec 09, 2025 4:07 pm ]
Post subject:  Re: Martin 1-18, 1918
FWIW, I use a 15’ back radius dish for all my guitars. But I think back when the original thread was generated, I had a home made radius board that had the radius across the width but was flat along the length. I would cut the side profile according to whatever plan and then sort of rock the body in the mold putting pressure at the neck block and transferring pressure to the tail block during the sweep. I’m sure it was never an exact radius but as long as it was smooth I called it good enough.

These days I have a custom workboard CNC’d that is the inside 2 feet of basically a 4ft radius dish, it is radiuses in all directions, so instead of ‘driving the bus’ it’s just a back and forth motion which is infinitely faster than rotating a radius dish…
Author:  RNRoberts [ Thu Dec 11, 2025 9:14 am ]
Post subject:  Re: Martin 1-18, 1918
Thomas,
In case you would find it useful, the link mentioned by Kevin Mason in his June 19, 2009 post above is:
https://www.mimf.com/library/Martin_siz ... -2009.html

Here's the similar one I made - cedar / flamed Hond. mahogany
Author:  tfchristie [ Thu Dec 11, 2025 9:45 pm ]
Post subject:  Re: Martin 1-18, 1918
Wow, that's a beaut, RNR. Thanks for the link and pics.

Ed, your early method sounds a little like Cumpiano's but his board was flat.

Not too many pics of old size 1s on the net. I see one from the 1850s and the back curvature is not very pronounced.
I think my sanding beam will be close enough to what Ed and Cumpiano did. I ended up with an understated but attractive curve on the back.
Maybe I will try the dish on the next one.
Thanks all
Author:  RNRoberts [ Fri Dec 12, 2025 9:53 am ]
Post subject:  Re: Martin 1-18, 1918
Thomas,

Fished out some other data that may be of use to you.

Top had 28 foot radius [dish]
Back 18 foot radius [dish]
(remember to flatten the top bout for the fretboard)

This second size 1 built had some experimentation that for whatever reason resulted in a somewhat fuller warmer voice in comparison to the above prototype, probably from widening the X brace which also dropped the bridge more into the sweet spot for a 24.9" 13 fret to body fretboard:
hybrid shorter 5" wide pyramid bridge with an added belly to maintain 6 sq inches of gluing surface vs the above 6" x 1" bridge.
widened the X brace to ~100 degrees [see dotted lines on template]
Slightly gentled the curve of the waist [again see dotted lines]
goofy X bracing of back
4 inch deep body [ the above one was 3 3/4]

Front view gives a better idea of body, which again was based on a Kinko's blow up of a 2" x 2" picture of an 1840 Martin carried by a union general through several major battles during the civil war, rather than the 1-18 plans, but appears to be what eventually came to be called the Martin size 1.

Also abandoned any attempt at being true to the era with inlays (not that the first one was either). It was for our son who at the time seemed to want to keep us in a state of constant anxiety with interests in flying, rock climbing, scuba, etc.

Both had a modification of Mike Doolin's adjustable neck.
Both have held up fine structurally after 20 years now in spite of the final bracing having been carved down (using Al Carruth's "tea leaf" methodology) far lighter than would have held up in a normal modern size body .
Author:  tfchristie [ Fri May 22, 2026 6:22 am ]
Post subject:  Re: Martin 1-18, 1918
RNR,
Thanks for the extra info!
I haven't had as much bench time as I would like.
I am just getting to making braces now.
I love your experimentation here. This being my first one, I am going to
stay pretty close to the plan. The hybrid bridge is a neat idea.
What was your reason for wanting to go shorter with it?
The X braced back looks like it might not be your first one.
Any general thoughts on advantages/effects you have noticed
from X vs ladder back?
Author:  RNRoberts [ Fri May 22, 2026 10:37 am ]
Post subject:  Re: Martin 1-18, 1918
Thomas,
As to the hybrid bridge, I think my reasoning was: as the bridge is also a major brace stiffening the top, shortening it lengthwise would help the top vibrate more freely. The “tacked on” belly was to regain gluing surface lost from the shortening. Once the guitar was finished, aesthetically the “mini” pyramids looked pretty ridiculous and the bridge overall pretty homely, and I resolved to never do that again…

As to the back X bracing scheme: It’s from the second Style 1-18 I tried which, if memory serves, aimed for an active vs a reflective back. The 18” radius on the back, which imparts a pretty significant curvature (which can be seen in the photo of the back if you look at it and maybe squint a little?). Especially with this small a body, that tight a radius significantly stiffens up the back. I thought what the heck, maybe an X would free it up some.

Also, I tended to what back then was called “left brain” lutherie, and Al Carruth’s “tea leaf” plate tuning made a lot of sense. With it, a symmetric bracing pattern like the X is easier to get where you want it than an asymmetric pattern. The "tea leaves" also resulted in the bracing having been carved down to so minimal (but after 17 years, apparently adequate) a height.

Whether the X was an improvement over the ladder bracing, or what any of the “experiments” were responsible for what, I’m afraid my remaining neurons can’t answer. But I like how it sounds.

I think it was Al that once said: “Half of everything we know about the guitar is wrong. That’s not the problem…the problem is: nobody knows which half.” Not a bad north star to follow when looking for advice.
Author:  doncaparker [ Fri May 22, 2026 11:48 am ]
Post subject:  Re: Martin 1-18, 1918
On the question of additional gluing surface for a pyramid bridge: In order to accomplish this, I have kept the bridge at 6" long (i.e., 6" across), but modestly widened it beyond the standard 1" width. I've used 1.25", and it looked pretty good. Wider than that and I think it will start to look a bit pudgy. Just an idea, one of many.
Author:  meddlingfool [ Fri May 22, 2026 1:53 pm ]
Post subject:  Re: Martin 1-18, 1918
Those back and side inlays are lovely!
Author:  tfchristie [ Sat May 23, 2026 2:10 pm ]
Post subject:  Re: Martin 1-18, 1918
Thanks for the notes and extra pics. I agree with meddlingfool regarding the back and sides.
If I had to choose between putting a belly bridge on this style guitar or your hybrid, I am not
sure the standard belly bridge would win. ;) I will probably experiment with X braced backs someday,
but not until I have at least 3 of these under my belt.

Don, I will probably go with a slightly wider pyramid bridge along with a slightly thicker fretboard
as the only deviations from the plans for this first build.
Author:  Ken Nagy [ Sat May 23, 2026 2:17 pm ]
Post subject:  Re: Martin 1-18, 1918
I agree with Ed 1,000%
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