INTRODUCTION: The following is my first complete bass guitar build. I learned a lot, made a lot of mistakes, read a lot, and sometimes just plain guessed on how to do certain things. The project took place over a seven month process on the weekends. I started to reduce the detail in my documentation here, but decided not to reduce it too much because you need to understand that this is not a project for the faint-hearted. There are far more steps to this process than I expected. If you decide to build one, your steps may change based upon your design, tools, experience, acquaintances, and skill level, but maybe my process will help you with some of the steps.
If I were to win the contest and win the grand prize, I would be closer to quitting my current job and concentrating on a business to design and make items for resale. That may include bass guitars. My background in computers, software, and manufacturing are all pieces to the foundation for my desire to expand my CNC and design skills.
Step 1: General Planning / Tools / Suppliers / Sketches
GENERAL PLANNING: The first step is to plan out what you want for a bass guitar. I currently have a bass and wanted to make one very similar, only with a smaller width neck. I have a CNC router, but this is by far the most complicated build adventure I have taken and it challenged my skills repeatedly. I have seen a CNC machine used to make guitar bodies and guitar necks, but my plan was to try to machine the entire thing - the body, neck, and headstock - all in one piece, since the plan is for a neck-through bass. In retrospect, it is advisable to plan out your guitar and purchase all of the components before starting your project. I did not do that simply because I wanted to get started with what I had - the wood. But not knowing all of the extra components and their sizes did cost me a lot of setup time. Repeatedly going through the setup process of putting the guitar back up on the router table within .005" multiple times is a pain, but I wanted it to be right.
TOOLS: These are the primary tools that I used: table saw, planer, hammers, digital caliper, many files, lots of clamps, router, cordless drill, various drill bits, small digital scales, dremel (with at least the cheap plastic base), spray paint equipment, headset magnifying glasses, dremel buffing wheel, and a CNC router with router bits helps. I had most of the tools but did have to buy a fret file and fret nippers for the planned fret work.
Other supplies include razor blades, carpet tape, painters tape, lots of sandpaper from 220 to 1000 grit, face masks/respirator, rubber gloves, wood glue, super glue, clear epoxy, feeler gauge, fret oil, polishing compound, binding tape, razor blades, ½" tap and tap handle (due to my table mounting process, and a board to mount the guitar onto for the routing). You’ll need the finishing material, but more on that later. Add in some 3D software for drawing the guitar. You should stock up on a lot of patience, too.
I ordered hardware and parts for the guitar throughout the process and will mention them at the point they came into the build process.
SUPPLIERS: These are the primary suppliers I used.
PLANNING THE GUITAR AND SKETCHING THE BUILD: My plan was to build a neck-through bass versus a bolt-on neck style. I also wanted to do the 3D routing over the full length at one time and then be able to flip it over to machine the back side.
The first step was to take my current guitar and sketch it out with any dimensional changes I planned. The following is just one of the sketches to show the detail I captured. I did separate sketches for the back side and the fingerboard to capture the dimensions accurately.
Step 2: Drawing
DRAWING THE 3D GUITAR: I needed to draw the guitar in a 3D software that would allow me to export drawings into a file that the CNC machine could understand. After extensive reading, I decided to buy Rhino 3D. I went through some Rhino tutorials and then started my 3D drawing. I started by importing a picture of my current guitar into the software and used it as a rough model, making dimensional changes where desired. I took my sketches with dimensions and continued the Rhino drawing until I completed what you see in the pictures. From here, I was able to export STL (stereolithography)3D files used by the CNC software for the top and bottom of the guitar and DXF (Autocad) files of the planned cutouts.
After trying to figure out how I was going to flip over the guitar so that the back side would be indexed with the front side, I decided to leave extra wood at the top and bottom so that I could put round ½" indexing mounting holes at each end of the guitar for bolting the guitar wood to a board. This would then allow me to flip it over on the center line and bolt it down to the board when I needed to cut the back side. On my drawing, I placed the center of the bottom indexing hole at X=1", Y=7". That way, if I needed to take the mounting board off of the routing table, I could always find the center point of the lower indexing hole and move the router X -1" and Y -7" to find my X and Y zero starting points. The following are pictures from Rhino.
Step 3: The Wood
WOOD PLANNING, PREPARATION, AND GLUING:
Note: Due to an iPhone update that deleted a many of my pictures, some that I wanted to include in here are not available. I did however have some pictures of the original ‘practice’ piece where I used the same general glue up and process and will include a couple where they provide some clarity to the process.
The center piece will be maple, which would be sandwiched by 1/8" pieces of walnut, sandwiched by two pieces of birdseye maple, with two small maple pieces to accommodate the width of the head; and the outside sections of the body will be walnut. I had all the wood except I that had to buy the maple center piece. I chose a particular piece of walnut for the body since it had a nice burl in the wood that I thought could integrate nicely into the design.
I used the planer to get the neck wood sized and square. I made the neck through section about 1 7/8" thick since it will finish at about 1 3/4". I glued the neck pieces first and waited for the glue to dry.
FINAL GLUE-UP: For the body pieces, I planed the piece of walnut that I had selected, split it in half, and cleaned up and straightened the edges that will be glued to the neck glue-up. Then I glued and clamped it all together until dry
Step 4: Mounting the guitar for indexing it's position
MOUNTING WOOD TO BOARD: I planned out and marked where to place some mounting holes through the guitar wood into a piece of veneer plywood to use for indexing the guitar on the board, which will be clamped to the router table. The pictures show where I drilled 27/64" holes through the wood above the head stock and below the body at points that will be outside of the full length of the guitar. Then I used a ½" tap to thread the holes in the mounting board only and then drilled out the guitar holes to ½". After the guitar is all done, the plan is to cut off these mounting areas.
Step 5: Body cutting
BODY CUTTING: Next I mounted the guitar to the mounting board and clamped the board to the router table. Then I exported the STL and DXF files from Rhino into the CNC software, created the 3D toolpaths, and cut the bottom 3D shape. Then I flipped it over, bolted it down and cut the front side 3D surface.
I created a perimeter cutout toolpath which included leaving the indexing mounting holes on the guitar. I should have waited to cut this out, but I got too anxious.
Here is where I started ordering some of the hardware for the guitar in order to figure out some cutout sizes. The Gotoh tuners and truss bar came from StewMac. After receiving and measuring some of the parts, I started on some of the drawings to create the toolpaths.
I flipped over and re-bolted the guitar to the mounting board (top up) in order to cut the truss bar slot. I spent some time on the X and Y alignment of the guitar to the CNC router to be sure it was almost perfect. I drew the required slot in the CNC software and created the toolpaths. While cutting the slot I broke my one and only expensive 1/8" end mill. I was in a rush as usual. It was going to take too long to get a new one so I decided to try a cheap dremel 1/8" bit. By slowing down a lot, I was able to complete the slot and inserted the truss rod for fit.
After measuring the tuners that came in, I drew them up, created toolpaths, and drilled the tuner holes.
I took the guitar off of the mounting board and cut off the index mounting alignment holes above the headstock and below the body. Next I did some sanding to clean off any rough areas where the mounting holes were located. I also started rough sanding edges along the edges of the neck. Then I ran a round-over bit around the body top and bottom to take off the sharp edges.
I installed the tuners to see how they looked.
Step 6: Pickup pockets
PICKUP POCKETS: I bought some Bartolini pickups and a preamp (from Bestbassgear) and used the software to draw the pockets for the pickups. I measured the height to strings on my current guitar which helped me calculate how deep to make the pockets. I figured out what position I wanted them, created toolpath cut files, and cut the pockets on the router. I made the pockets about .025" bigger than the pickups - for clearance.
Step 7: Electronics pocket covers
PREAMP AND BATTERY POCKET COVERS: I flipped over the guitar and clamped it down, spending some time to get close alignment again on the X and Y axis of the CNC router. This took a little longer to get aligned since I had already cut off the alignment mounting holes.
My preamp was a Bartolini pre-wired unit. I measured all of the components and determined how I wanted them to be placed on the guitar body. I sketched things out and then used the software to roughly draw the components and place them approximately where I wanted them. The next step was to draw the cutout for the pockets, leaving a perimeter area where the pocket covers will mount. I also allowed areas for where the cover screws would be placed. I figured out depths for the each of the cuts. I did the same for the battery pocket and cover, and created toolpaths (the path the router bit will take) for everything.
I had purchased some back plate material from BestBassGear and created the toolpaths for the covers, about .010" smaller than the shallow pockets where the covers would sit. With the matt finish side up, I used some carpet tape to mount the material to the CNC router table, and cut out the plate covers so that I could use them for final sizing of the pockets that I would be cutting into the guitar body.
Step 8: Electronics pockets and drilling
ELECTRONICS POCKETS: The next step was to pocket cut the electronics and battery areas. First, were the shallow cuts for the covers. Once cut, I fit both pocket covers to ensure the fit was fine. Then I cut out the deeper pockets for the electronics and battery. I followed up by measuring each of the electronics potentiometer shafts and drilled the six holes for them - with slight clearance.
HOLE DRILLING: The next process was to drill some holes - one for the amp jack, others between the preamp, the battery pocket, and both pickup pockets. Most were easy enough since the angles were not that great between pockets, but the challenging one was between the preamp pocket and the front pickup pocket. That’s where I used a 10" long ¼" drill bit. I turned the body on its side, put the drill bit through the amp jack hole, and ‘eyeballed’ the angle to try to hit the front pocket. I was extremely fortunate and it hit the perfect spot at the bottom edge of the pickup pocket.
Step 9: Fingerboard
FINGERBOARD: I ordered an ebony bass guitar fingerboard and binding from LMII. I decided to order some bloodwood colored purfling to include in the binding of the fingerboard.
Since I did not have the special saw blade for cutting the fret slots, I originally planned to have LMII machine the radius and slot the fingerboard. But, I had been talking to a friend of mine, Tim of Mcknight Guitars, who had already made a fixture to be able to cut the slots on my fingerboard. Since he had the special saw blade and offered to cut the slots in the fingerboard, after the board came in, I took it to him to slot. This is a 35" scale, 22 fret fingerboard.
I went back to Rhino to draw the 3D fingerboard with a 16" radius.
Next, I exported the fingerboard radius 3D STL file from Rhino, imported it into the CNC software, aligned the fingerboard on the CNC router, and used carpet tape to place the board on the CNC router table. I used some plastic sheet stock beside the fingerboard
Step 10: Fingerboard cutting, gluing, and sanding
FINGERBOARD CUTTING: The next step was to cutout the fingerboard to closely match the neck width and length where it would mount. Since my plan was to add the purfling and binding, I had to adjust my cutout by using the neck drawing details from earlier and offsetting them to the proper dimension. So that when the purfling and binding were glued to the fingerboard, the size would be about .015" per side wider than the neck surface that was cut earlier. The plan was to be able to sand them flush after gluing to the neck. I created toolpaths and cutout the fingerboard.
FINGERBOARD GLUING: Then, I glued up the fingerboard and used binding tape to hold it all together. I had taken a razor knife and ground the blade tip the same width as the fret slots for cleaning the slots. I positioned the binding tape so as not to cover the fret slots; so when I glued on the purfling and binding, I could clean out any excess glue that squeezed into the fret slots.
FINGERBOARD SANDING: For sanding the fingerboard, I did not have a special sanding block; but I did have some 60 year old hardwood. I took a 3x3x28" piece of old walnut to use for the sanding block. Back to Rhino to draw up a reverse 16" radius for the block, export the STL to the CNC, and cut the radius. I put some stick-on sandpaper on the radius and started sanding. It was hard to sand straight, so I aligned a straight edged block of wood with the center line of the fingerboard, and then sanded the fingerboard down with 220 grit, 320, 500, and then 800 grit.
Step 11: Fingerboard Inlay dots and sanding
FINGERBOARD INLAY DOTS: I had ordered some pearl pieces from Grizzly that I wanted to use for the fingerboard dots and the name inlay I had planned for the headstock. I was not sure I could cut the pearl with the CNC; but I used carpet tape to attach a pearl blank to the router’s bed, drew up some circle dots on the CNC software, created toolpaths, and cut all of the dots out of one 1 3/16" X 2" piece of pearl.
FINGERBOARD DOT SANDING: I marked the position of the inlay dots and used a pilot drill to put the holes in the fingerboard. While drilling I kept checking the depth using the back end of the digital caliper until I got the holes around .015" shallower than the dot thickness. The next step was to use CA glue and install the dots. I then used my 3X3 sanding radius block and sanded the dots down flush with the fingerboard.
Step 12: Gluing fingerboard to guitar
GLUING FINGERBOARD: Then it was time for gluing the fingerboard to the neck. For my clamping fixture, I used the long sanding block, which I knew was straight.
FINGERBOARD FINAL SANDING: After the glue dried, I used the sanding block to sand the fingerboard level again.
Step 13: Pearl side dot markers and install bridge
PEARL SIDE DOT MARKERS: I bought small pearl dots for the side of the fingerboard. Since the fingerboard was already glued to the neck, drilling for the dots was going to be difficult for those located over the guitar body. I decided to just hand drill them.
BRIDGE POSITIONING: Next, it was time to set the Schaller Bridge (from Warmoth). I laid out the position for the 35" scale and screwed it down temporarily.
Step 14: Pearl inlay for headstock
HEADSTOCK INLAY: I had planned some inlay for the headstock. I decided to inlay pearl letters of my last name into a piece of ebony (scrap end from the fingerboard) and inlay that into the headstock. I decided to try my hand at cutting the pearl lettering on the CNC. I created some letter toothpaths; but then had to modify them a bit to ensure that the .090" router bit would have clearance all around letter.
I ended up being able to cut all of the letters out of one piece of the 1 3/16" X 2" pearl stock.
PEARL INTO EBONY: I had never inlayed anything before, so the step of inlaying the pearl into the ebony was extremely time consuming. I went to the web for a bunch of reading to learn more about this process. I spot glued the letters to the ebony and traced around them with a sharp razor blade tip. I removed the letters with the razor; and then, by using a very small dremel bit and my magnifying headset, I spent about 40 minutes per letter slowly routing out the lettering with the dremel to a depth slightly less than the thickness of the pearl. Once that was done, I sanded down some ebony scraps to create ebony dust and mixed it with some clear epoxy. Then I put some of the epoxy mix under the letters and clamped them down into the ebony, and let it sit until dry.
EBONY INLAY INTO HEADSTOCK: I designed the shape of the ebony to inlay into the headstock and created a drawing and toolpaths to cut the headstock pocket. I sanded down the thickness of the ebony to about 1/8" and mounted it to the CNC table with the carpet tape and then cut out the shape. Using the same drawing as used for the headstock pocket, I offset the line by .005" and used it to cut the pocket in the headstock at slightly less depth than the ebony. I used more of the epoxy to glue the ebony into the headstock pocket and clamped. After it was dry, I sanded the pearl and ebony down to the level of the headstock.
Step 15: Installing fret wire
FRET WIRE INSTALL: It was then time for the fret install (gold Evo fret wire from LMII), so it was back to the internet for more reading. I started on the wide end of the fingerboard and cut a piece of fret wire about 1/8" wider on each side than the fingerboard. I did not have a fret tang nipper, so I used the fret wire cutter from Stewmac to trim back the tangs to clear the bindings. After I cut off each fret from the wire stock, I turned them over to file off the tang on the ends so they would fit over the binding.
Using a brass headed hammer, I centered the frets and tapped them into place. Using a hardwood block, I hammered them into place. Some were a bit stubborn, so used the brass hammer directly.
After they were installed, I used the fret nipper to trim the frets close to the neck.
Step 16: Fret wire sanding, radiusing, and polish
FRET WIRE SIDE SANDING: I had seen some blocks used for filing down the fret ends, so I looked up some details on the internet, and made a block, with one side being 35 degrees. I used a table saw to cut a slot in the wood block so that my file would press into it. I used the fret cutter to clip off the fret ends and began the fret end filing.
I now needed to level the frets. Setting the neck level using the truss bar adjustment, I leveled the frets using the large radius block that I had made for the fingerboard sanding. Since the frets were not far off, I was able to use 600 grit sandpaper with light sanding.
FRET WIRE RADIUSING: The next process was to radius using the fret file. I used a black marker to mark across the top of each fret and then I started filing down the frets until just a fine marker line was on top of each one. Using a 3-corner file that I had ground smooth on the sharp edge, I took the edge sharpness off of the fret ends. Then I used various grades of sandpaper to sand the file marks from the frets as well as the fret ends. The final sandpaper was 1000 grit.
FRET POLISHING: Next was polishing the frets with the dremel polishing wheel. I used a coarse grade of polishing compound, followed by the fine grade made by Dupont. This gold Evo fret wire material really looks nice after polishing.
Step 17: Truss rod cover
TRUSS ROD COVER PLANNING/CUTTING: It was time to plan out the truss rod cover that covers the head stock access to the rod. I had looked at purchasing one but could not find anything, because the radius on my headstock up by the nut had a radius that I would not be able to match with a purchased cover. After discovering that the radius matched exactly with the curve on a silver dollar, I decided to draw up a side profile of the cover’s shape in order to come up with something acceptable. I created some toolpaths, clamped a piece of 1" thick walnut (from the body’s leftovers) to the router table, and cut out the profile shape.
THE CROSS COVER: I wanted to make this truss cover unique and since the bass guitar will be used predominately in a contemporary church service, I decided to make it into the shape of a cross. I made a drawing and toolpaths for the cross, carpet taped the walnut piece to the router table, and cut out the cross portion of the shape of the truss rod cover. I did some minor blending and sanding and laid it on the guitar headstock to see the fit. I will place some hold-down screws in strategic locations later.
Step 18: Washcoat
WASHCOAT: The sealer, reducer, and stringed instrument lacquer are Behlen products that I ordered from Grizzly.
The first step was to sand the guitar body and neck and then wipe it down to get ready to spray on a wash coat, which is a thinned down finish or sealer. I taped up the fingerboard to get ready for spraying. After realizing that I did not have a very good method to handle the guitar for spraying, I built a gallows type structure from 2X4’s and other wood scraps that I had lying around. I hung the guitar, wiped it down, mixed some material for the wash coat, put on my respirator, and sprayed on a coat. I waited a couple of hours and added another coat.
Step 19: Pore fill & Finishing
PORE FILL: Walnut wood has a lot of pores that must be filled to get a smooth finish. The first mistake I made at this point was thinking that Behlen’s natural pore filler (which I had already purchased) was clear. Opening the can clarified my misunderstanding. It was not clear. After a conversation with a friend and some additional reading, I ended up buying clear epoxy for the pore filling process. I used System 3 epoxy from LMII for the pore filling. After light sanding and wiping down the guitar, I applied the epoxy per the instructions on LMII’s site. The mixture is supposed to be very accurate for the epoxy to cure properly, so this is where I used the small digital scales. A few ounces goes a long way. I worked in small areas, applying some epoxy and using a hotel room key card to scrape off the excess. Once this dried 24 hours later, I sanded level with 320 grit sandpaper. It appeared that there were still a few open pores, so I applied another coat of epoxy. I let this dry for a week before sanding with 320 grit.
FINISHING: Next I applied two coats of Behlen Vinyl sealer, per the manufacturer’s instructions. I applied 5 coats of lacquer, allowing drying time and completing sanding with 320-400 grit between coats.
Step 20: The nut
THE NUT: Now it was time to work on the nut. I measured where the nut would be placed and rough cut out the bone nut material to within .020" or so of its final size. Then I slowly sanded the width to size. Then I set it in place and traced the radius of the fingerboard, decided how much to add for the height of the nut, marked, and sanded the top radius and shape.
Then it was time to cut the slots for the guitar strings. I had purchased some strings and measured each of them to ensure correct sizing of the slots. I did not have fret wire files and was already way over budget; so I took a set of small files that I had, and modified them where needed in order to be able to cut the slots. I gauged the nut slot depths based upon my old guitar. After doing some more reading, I figured out about about where the final depth would be. I stopped a little shy, so that I could fine tune the depth later - if needed.
Step 21: Bass guitar assembly
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ASSEMBLY: The number of days the instrument stringed lacquer should sit on the guitar before buffing varies by opinion, so I plan on leaving it about 3 or 4 weeks before polishing and buffing. Since 3 weeks will be beyond the deadline for posting this, I decided to go ahead and assemble the guitar for pictures. I installed all of the components. The electronics are pretty straight forward since the pre-amp is pre-wired and adequate documentation comes with it. The last setup was to install the strings and confirm the setup height.
After the 3 or 4 weeks, I will use various grades of sandpaper and polish the guitar to bring it to the desired shine, reassemble it completely, and do the final pickup and string height setup (which were very close to being correct when first assembled), and oil the fingerboard. Then - serial number 1 will be done.
Step 22: Final Comment
Most of my challenges to creativity and ingenuity were in the areas of learning and designing in the 3D software where I had no experience. My knowhow was also challenged repeatedly as I tried to figure out how to do the inlays and accomplish the many, many steps in the fingerboard and fretting process.
If you decide to take on the project of making your own bass guitar, buy as many of the specialized tools as you can afford, since they can speed up the job dramatically. Definitely buy as many of the guitar components up front before the build in order to take precise measurements for cutting pockets, holes, etc.
Prepare to challenge your creativity, ingenuity, and knowhow - and enjoy the adventure just as I did.