Building a Clone of a 1930 Martin 0-18 Guitar

February 2024

I am building a Martin 0-18 style acoustic guitar from a box of Martin Guitar parts I bought from the Guitar Maker's Connection in 2017. The guitar will have a 12-fret neck as was done in 1930 by Martin Guitar. It should look something like this guitar image I found of a 1930 0-18: solid spruce top, solid mahogany back and neck.

I am using my own webpage as a building guide, and I have reopened my guitar making books by Kinkead and Cumpiano/Natelson. I will also refer to the plan for a 1940's 00-format guitar on the page below to confirm layout and brace sizes and shapes where appropriate:

https://www.grellier.fr/en/downloads

The box of parts contains these things:

One joined spruce top, a set of scalloped spruce braces, fingerboard, bridge (rosewood or richlite?), binding and purfling strips. Mahogany parts: back in two halves, neck, kerfing strips, neck and tail blocks (not shown above).

I made a template in Inkscape based outlines of 0-18 guitars and traditional x-bracing I found on line. Helpful site: http://martinrep.com/


I sent the file to my son who used his laser to cut the template out of cardboard. I will use this to draw outlines for the braces on the sound board.

Here is my old mold, for the 000-28 guitar I finished in 2017. The mold is too wide for the 0-18 body so I traced an insert, cut it out of scrap plywood with the band saw. The insert is sitting on the right inside edge of the mold. The cardboard shape is a simple body template I cut out with scissors, to help me modify the mold.

I cut five more inserts using the first as a pattern. I screwed together two sets of 3 inserts and screwed them to the sides of the old mold, to yield this new mold:

I sanded down some irregular bumps in the sides of the mold on the spindle sander.

I have an old Epiphone acoustic guitar with a broken neck, but it has good mahogany veneer sides. I extracted the sides with the band saw. I use a trim router to grind off the old kerfing and then cleaned the sides up with a spindle sander.

I chose to believe that the veneer sides will not have much impact on the tone of the guitar which will be otherwise made of solid mahogany and spruce. I stuffed the sides in the mold to mark where I should cut them to fit.


After trimming the sides, I clamped them to hold the blocks in place.


I glued up the neck and tail blocks out of the mold to get secure clamping on the top and bottom of the blocks.


Here are the sides back in the mold with blocks glued on. The dimensions match those of a 0-18 guitar except for depth which is too deep.


Here is the lower bout measure, very close to 13.5".


I used the spindle sander to take a little off the front edges and a little more off the back.


I leveled the edges by sanding them with a big sanding disk that rotates on a pipe clamped to the workbench.

Ready to install kerfing.


One side glued, clamped with clothespins.


I left the clamps on for two hours, then removed them to do the other side. Kerfing done.

I'm getting ready to cut circles in the sound board for the rosette, and I have to cut out the sound hole. I want to cut two 1-mm deep rings with a Dremel and circle cutter. For practice I cut several slots in a cut-off from the spruce top, to see how the spruce will behave.


I determined type and size of the rosette by looking at rosettes everywhere. I decided on a simple rosette: one 1/8" inner ring, 1/16" outer ring.

I used my laser template to transfer the patterns to the sound board.



I drilled a small hole through the board where there is a marked hole at the center of the sound hole. I used my father's compass to draw concentric rings using the small hole as the center.


After drawing the rings, I drilled out the small hole with a 1/8" drill bit to accommodate the centering pin of the Dremel circle cutter.

First ring cut:

Here is a video of the cutting of the second ring:

A close-up after cutting the second ring, lightly sanded.


I have some purfling but I need a white strip to go with a black strip, for the outer ring. Try Blender.

3d print:


I had to sand the strip to match the thickness of the black strip. Dry fit here. The breaks in the purfling will be hidden by the fingerboard:


I tried block sanding after gluing the purfling in with CA glue. It was slow going and seemed to dirty the sound board with purfling dust.



The air sander with dust removing air holes worked faster and better.


Preliminary rosette sanding done. There will be more sanding later. Here is a close-up after air-sanding and blowing dust away with compressed air.


I cut out the sound hole using the Dremel and circle cutter. I did a total of 3 1-mm deep passes to cut out the hole.


A view of the back with the template pattern. Ready to cut out the sound board.


I have decided to use shellac as a primer/sealer for the sound board so I took a detour to make a tumbler to mix shellac flakes. It was a fun detour that takes us into March. The working tumbler can be seen here and here is a picture:


I had to turn the scrap pipes on the lathe before I could get it to turn.


March 2024

I made 4 oz. of shellac and I can always make more. This is "2-pound cut" shellac from Platina flakes, fresh out of the tumbler, filtered through a coffee filter.


Back to the soundboard. I placed all the braces on the marked sound board after tracing the guitar body.


These braces are sized for a larger guitar. The x-braces and tone bars should be 1/4" wide for a 0-18 guitar. Here I have marked the 5/16" braces on each side to show the 1/4" remaining.


I extended the lines to guide me as I sand the edges away.


Sanding.


As I get ready to glue the braces, I am triple-checking the bracing pattern. It appears that 1930's 0-18 Martin guitars had only one finger brace on each side and one tone bar at the bottom, as shown on this site:

https://umgf.com/steel-string-bracing-on-pre-1930s-parlor-sized-mar-t110663-s20.html

 I have arranged the braces accordingly, and I cut two cleats out of spruce scraps to follow the 1930 image:


The bits of spruce near the X of the braces will serve as shims to get a better fit at the X. When I sanded the x-braces, it left small gaps in the notches.

Ready to glue the x-braces. I used the go-bar deck from my first guitar build to secure blocks to trap the braces so they won't slide around during the glue up.


After I glued the braces, I removed the blocks as soon as the braces were secure, to scrape away squeeze out. I put a square cap on the X to provide a solid point for the go-bar to sit on.


Upper braces glued on.


All the rest including diamond cut cleats.


Carving braces requires sharp chisels. Sparks fly. I built this chisel holder from spare parts, got the idea here  https://www.youtube.com/watch?v=4uei2HYv9RA


This is a practice board for chiseling. I already gouged the hardboard once. More practice needed.


I must prepare the guitar body to accept the soundboard. The top must be sanded flat. To sand the kerfing I rotated this sanding disk back and forth against the top edge of the guitar body.


Sanding.


I scribbled pencil lines on the kerfing and blocks so I could see the progress while sanding.


You can see sanded vs unsanded areas if you follow the right side from the bottom up, for example.


Top sanded flat.


I touched up the top edge by rotating a 28' radiused sanding block over the top.

I disk-sanded the back, then radiused the edges by sanding down the center with this block. The back will have this same 15' radius.


Sanded back.


More carving practice, with a sharper chisel.


Between practices I worked on the back. I cut a strip off one back board to eliminate a pin hole in one of the boards.Then I cut the same width strip off the other board to maintain book matching.


I ran the boards across the jointer.  Here they are getting fitted for the nail press.


 I set up the pieces: the boards, non-stick baking paper to repel glue, a clamping caul (a straight piece of window casing) and a Home Depot wooden ruler underneath. I tested go-bar tension with a single go-bar.


After applying glue to the edges of the boards,  I fit them together and removed the ruler. This forces the edges together for a tight fit.

All clamped up, for 24 hours.


The joined back. The straight piece of spruce at the bottom is from a leftover piece of spruce soundboard. I will glue it to the back to reinforce the joint between the two boards.


I sanded the back with the air sander with 80 grit paper, to clean the whole surface on each side and to remove excess glue.


I must glue side braces on before installing the top and back. I cut mahogany braces from a piece I trimmed off the back boards. Glue and tape.


I put 3 braces on each side.

To cut out the back, I used a template of the body shape, left over from the top brace template, to draw the shape. I found a clear area, centered the template over the joint.

Cut it out with the bandsaw.

Sand it with the air sander, 80 grit paper.


The spruce strip I intended to use for a back reinforcement strip turns out to have the wrong grain orientation. The grain of the strip must run perpendicular to the joint in order to strengthen the joint. Ah! The back brace kit has spruce reinforcement strips! Note the grain orientation on the top strip here.


I clamped a ruler beside the strips to help align them while gluing.The wood piece below is a clamping caul.


Clamped strip.


After an hour I removed the ruler and caul so I could scrape the glue away. I should have chosen a narrower caul. I would have had access with a paper towel to wipe the glue away.


A sanding block is used to remove the excess glue.


Also sand the top and edges of the strip.


March 22

More practice carving braces.  This video was very helpful. Beginner's carving tips.
I made a stropping block by gluing a piece of leather to a block of wood and rubbing green polishing compound into the leather. When the chisel begins to labor, I strop the chisel once on each side to remove any burr that might be forming. This brings the chisel back to life. Eventually or sooner I will have to sharpen the chisel again.


I drew a line on a practice brace.


Carving.


The braces will be smoothed with sandpaper, chisel, plane?


Practice is over. I drew approximate cut lines with a ruler and pencil. Cutting the first soundboard brace.


The uppermost flat brace needs to be cut on each side. I should have done that before I glued it on! I used my old fret saw to cut most of the way through the brace.


Cut.


Chisel out the end.


Almost there. Sand with a little sanding block to get the rest.


I knew I was close enough when I could see the pencil lines.


The tone bar is sanded till it's level with the soundboard. I put two pieces of painters tape on the board knowing I might slip while chiseling. True. The tape protected the board.


To finish the end of the tone bar and the ends of the finger braces, I made a curved sanding block that matched the tone bar curve. I cut the curve out of a scrap of wood on the band saw.


I chiseled and sanded the two diamond cleats.


Braces carved except for the end details where they will fit under the kerfing.


While cutting the kerf for brace ends, the chisel slipped, broke corners off the kerfing. I glued pieces on, will sand them down to match the adjacent kerfing.


I tried the Dremel next. Easier to guide, it took away what I wanted.


It should be easier to dry fit the back before the top goes on so I will work on the back braces. I approximated where to put the back braces by eye, based on diagrams of other small guitars.  I scored the back strip with a utility knife, at the edges of the brace channels.



To make gaps in the back strip for the braces I had to use a 1/4" chisel because the gaps are smaller than 1/2". I put two layers of painter's tape behind the strip for protection.


All gaps cut. Note the light pencil marks, more visible at the bottom. These will help me align the braces when I glue them on.


Dry fit.


I dry fit all the braces in the go-bar deck. To prepare for this step I cut two more 15' radius blocks on the band saw, so I could glue all four braces at once.


First brace clamped in place.


This much glue. I spread it evenly with my finger along the brace before putting it in place.


All back braces glued up. I wiped away most of the squeezed out glue with damp paper towels.


I let this sit for 24 hours.  I aligned the back with the body and marked where the braces meet the lower kerfing.


Again, these braces were designed for a larger guitar so I have to trim the ends to fit. Since I am using only one tone bar, I used the spare as a template to draw cut lines on the brace ends. I also drew a straight line 16mm above the bases of the two largest braces to match the profile of braces for smaller guitars.

Only needs occasional stropping to keep it sharp.

The sanding block fits the brace curve.

May 2024

I took a break because Spring came and called me outside. There was also a solar eclipse that called me to Ohio.

I took up the chisel again. Here I do final cutting on the back braces.


Working on the top now, I mark the kerfing where the top braces meet.


I routed out the kerfing with the Dremel. I did this for each brace. Here are the top and back, kerfing cut.


The fit was too tight for some braces. I zeroed in on the fit by using a piece of paper as a thickness gauge. I pushed on the guitar sides with paper in place. If the paper was tight, I scraped the brace with the chisel just until I was able to pull the paper out.


Ready to glue the top, I put the guitar body, still in the mold, on the go-bar deck, squeezed wood glue on the kerfing and blocks.


This much glue. I smeared it around with my finger to evenly cover the kerfing and blocks. The mirror in the center allowed me to check the fit through the sound hole with the top on.


Glued up. I used the clamping cull that I used on the 000 I finished in 2017. Just fits.


Ready to glue the back.




Oversized top and back glued up, as planned.


I will trim the top and back with a trim router with flush-trim bit. For practice, I secured a scrap piece of pine to a scrap guitar using double-sided tape.


On the first pass, the spinning router bit slipped out of the router and made a big gash in the scrap guitar! This is why I practice.


I tightened the bit more securely. I taped a piece of hardboard for a second try. 
This picture also shows the trim router with bit. The bit has a small bearing on the end to allow me to follow the curve of the guitar body.


Works. The painter's tape helps protect the guitar body from small scratches.


Now for the real deal. Trimmed back.


Trimmed top.
It looks like a guitar body!


June, 2024

The next step is to rout the back and top edges for binding. I want to first give the spruce top a protective layer to reduce feathering of the wood fibers and protect the light colored spruce from darker mahogany staining.  Before that I needed to find the bridge location and tape it off. This is to insure good adhesion when I glue the bridge to the spruce top.

The scale length of this 24.9" short scale Martin guitar is actually 24.84". I used a Stew-Mac page to verify this:

https://www.stewmac.com/video-and-ideas/online-resources/learn-about-guitar-and-instrument-fretting-and-fretwork/scale-length-explained/

To accurately measure this, I have to fit the neck and fingerboard to the guitar body. I cut the spruce above the dovetail with a coping saw.


I used a rasp to clean up the cut.


Close enough for estimating.


The 12th fret slot sits at the top of the body as it should.


I carefully measured the distance from the nut slot to the middle of the bridge saddle, put down a piece of blue painter's tape. I marked the bridge outline and cut out the bridge shape a little inside the line. This should be close enough. It may change slightly when the neck is attached to the guitar.


Ready to put on a thin shellac coat.


A practice cut on the scrap guitar using the trim router:


OK.


Routed back.


Routed top.


Binding glued on with Duco Cement, taped firmly. Messy job. Allow to dry for 24 hours.


At first I didn't put enough glue on. The glue is relatively thin and runny so was hesitant to glop it on. The result, loose binding in one area. Rats:



I tried to reglue but got similar results. Rethink.

July 2024

Try new, wider binding and a better glue method. First rout wider channels:


Tape on binding.


Wick in 2 or 3 drops of very thin CA glue between tape.


Sanded binding, top.


And back.


Glue end trim with medium CA glue. Note the chipped side wood. Maybe I should have routed the channels in several thin passes.


August 2024

I tried several wood fillers to fill the chipped areas. Work in progress.


To set the neck in the body, I cut a 10 degree angle to make a sanding block.

To hold the neck in a vise, I cut a semi-circle in a block of wood. I used Mister Copy from my father's tool box to draw shape on the block.



I cut the semi-circle on the band saw. Here is the block in action.

Initially, the neck sits about a 1/4" above the body.


I measured the height of the neck above the body with a ruler:


Then I measured the height of a straight edge along the neck to the tape where the bridge will be attached. This should be about 3/32" higher than the height of neck above the body.


It is not quite there, so I sanded the lower end of the heel to get the correct angle of the neck to the guitar body, using self-stick 60 grit sandpaper.

John Hall from Blues Creek Guitars has many helpful videos including this one about setting a guitar neck: https://www.youtube.com/watch?v=FNcbA1P95KE.



I took my time knowing that this is a critical step to getting a playable guitar. Sand, measure, sand, measure,...

I checked the side-to-side status of the neck as I progressed. The neck should be centered on the body, and it is.


When I was satisfied with the neck angle, I proceeded to sand the edges of the dovetail tenon, using the sloped side of sanding block, to lower the neck into the dovetail.


After much sanding and checking, the neck now sits just proud of the body.


A final measure to be sure before gluing on the neck. Straight edge on the neck.


Measure at the tape, just about 3/32".


Before gluing the neck, I cut a heel cap out of a scrap piece of black ABS.


With the neck in position, I glued the cap to the heel of the neck with medium CA glue.


Glue smeared on contact surfaces.


Clamped.


The next day I glued on the fingerboard. First I pulled one of the alignment pins from the neck.


Then I took sanding block and paper,


sanded the neck and body to sand down the slightly proud neck to match the body.


Looks flat to me.


Test fit the truss rod. I had to carve away a small bit of sound board to accommodate the truss rod.


I did a dry fit with 5 clamps, then ran a bead of glue along the truss rod channel, dropped in the truss rod and spread glue over the neck and body. I also reinserted the alignment pin.


I spread glue on the fingerboard and clamped it down. Good squeeze out. Clamping cauls on the top and bottom.


Let this sit for 24 hours. I wiped off as much glue as I could, will sand later. Note the top clamping cull is made of three pieces, to insure pressure along the edges of the fingerboard.


I examined the tuning machines from three scrap guitars.


I was able to use shafts and screws from one set, gears, knobs and plates from another set. Here they are, polished and oiled.


To make side dots, I center-punched the side of the fingerboard with marks at frets 3,5,7, 9 and two marks at fret 12.

To size the drill I made test holes until I got a tight fit.


Drilling.


Into each hole I inserted the white plastic rod with glue and clipped off the extra. I let it dry for a day, then sanded the edge smooth.


Matin 0-18 necks had only 3 dots on the fretboard, at frets 3, 5 and 7. The mother of pearl dots decrease in size from about 6 mm to 5 mm to 4 mm. I have 6 mm dots so I had find a way to shrink the dots. After some experiments, I mounted a dot on a dowel with medium CA glue.


Then I sanded it on the lathe with sandpaper on a stick.


I found numbered drills close enough to fit the dots. Dots and holes.


I wicked thin CA glue into the dot holes.


I quickly wiped any CA glue off the fingerboard with acetone to prevent staining. Dots.


I chose to make an authentic ebony nut because I had a scrap of ebony in my collection of parts. It cut easily on the metal-cutting band saw.


After some practice, got a flat, square nut of the proper dimensions, 50x20x10 mm, final sanding by hand on 100 grit paper over a flat grinding stone.


I scored a line on the head stock veneer with a utility knife using the nut as a guide.


Chisel, saw, file away till the nut fits.


Clear slot.


Nut fits.


September 2024

I unrolled the fret wire. Hey, the guitar is starting to look like a guitar!


I laid the fret wire across the fret board, estimated an 1/8" overhand on each side, then I clipped the fret wire with nippers. I placed them in order on the work mat from shortest to longest.


I squeezed a bead of Titebond glue on the fret tang.


I inserted the fret into the slot and banged it in with a plastic-headed mallet. Here is the second fret hammered in.


I wiped off excess glue with a damp paper towel after each fret. Near the end, showing the hammer head.


I filed each fret with a mill file, first filing vertically to the fret board.


Then I beveled the fret ends at a 30 to 40 degree angle.



Over the guitar body I had to file the remaining frets holding the file along the length of the fret board. I protected the body with blue tape and wrapped a hacksaw blade to slide the file against.


Fret ends smooth.


Bridge next. I had a blank Martin bridge among my parts. Research suggests a 2 5/16" string spacing at the bridge for a 1930 0-18 so I measured and center-punched the bridge with 6 points across the bridge.


Drilled with 3/16" bit.


Countersinking holes.


Getting ready to glue the bridge, I lined up mason's line from the nut to the end of the guitar, passing the lines over the first and last bridge holes.


I previously finish sanded the top (not shown) so I did not want glue to squeeze out onto the clean sound board. To prevent this, I taped the sound board area. Here I draw a pencil outline of the correctly oriented bridge.


I scored a line just inside the pencil outline.




I roughed up the sound board with 100 grit paper, to improve glue adhesion.


Bridge mounting stuff. The triangle caul gets taped to interior bridge plate to facilitate clamp up.


This much glue.


The glue squeezed out onto the tape as planned. I was busy gluing. No picture of the squeeze out. Bridge clamped, tape removed taking almost all the squeeze out with it.


Next day.


I covered the sanded sound board and sanded the neck and back using 220, 320 and 400 grit papers.




I used a round rasp to cut string channels in the headstock.




I rolled sandpaper around a pencil, sanded with 100, then 220 paper.


I punched marks for pilot holes for small tuner machine wood screws.


Installed.

I drilled through the wood and glue in the bridge holes with a 3/16" bit.


I reamed the holes until the bridge pins fit to the collar of the pin.


I made fresh shellac. Finishing soon.


I practiced marking and notching on the first nut I made. I marked it with compensated spacing using the diagram I used for my other acoustic guitar build: nut layout


I put the nut in the vise equipped with wood jaws and filed marks deeper with a small triangular file.


The compensated bone saddle was too wide for the saddle slot in the bridge so I sanded it down. I found it easier to hold the saddle if it was double-sided taped to a wood block.


Saddle in place, tight.


Strung!


Second try with a new nut blank. I marked a small ruler with equidistant string spacing based on the length of the nut, and 3mm margin to the fret bevel.


I marked and notched the nut as I did on practice nut, then filed each slot with the corresponding nozzle cleaner as I did on the 000 guitar.


I sanded a pencil in half lengthwise using the belt sander, sanded a sharp point.


I drew a fine line on the nut as I slid the pencil on the flat side over the first frets. The goal is to file the slots until the filed slot reaches the line. This was tedious because I didn't want to go too far.


I got close but I wanted to have low action so I continued to file and check each slot with the nut in place.


After many guesses and checks, I got the measurement between string and first fret to be 0.004 to 0.006" with the string pressed between the second and third fret.


The nut, not glued in yet. I will sand down the top of the nut so that the strings are not buried in the wood.


There was some fret buzz. I checked the neck for straightness, found it had a slight hump.


I turned the truss rod about a quarter turn counterclockwise to straighten it out. Happy enough with the action for now, I removed the strings, taped up the fingerboard and bridge, and applied a couple layers of shellac.


The back.


I learned how to shellac by watching youtube videos by Pablo Requena and others. It takes time but it is not too hard, and much less stressful and much less toxic than spraying lacquer. It is forgiving enough if you make a few mistakes. Here I sand back some blemishes with 320 paper.


I more layers of shellac over a few days, then started adding a few drops of oil to the shellac. Then more shellac.

Then "spiriting off" with a pad holding only a few squirts of very dilute shellac.


Watch youtube videos by Pablo Requena as mentioned above for polishing details.

Now, September 29, 2024, I remounted the nut and tuning machines and restrung the guitar.


I will play it and make adjustments as required. Then I will review the guitar.