Introduction: Building Mandolin No. 002
This project is a sequel to my first mandolin project, Building Mandolin No. 001. Like my first mandolin, the design is fairly untraditional. For one, it only has four strings compared with a mandolins typical eight. This fact alone has drawn the ire of many a mandolin purist.
This mandolin was much faster to build than my first one, but still took awhile: I did the majority of the construction in about two weeks with around 40 hours of build time. It took another week and 20 hours to complete the mandolin after a two month hiatus. It cost less than $100 for all of the materials for this mandolin making it a relatively inexpensive project considering the end product.
For more information about my first and second mandolin projects (including plans for both), check out my website: thewidgetforge.com
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Making the Form
The form is a very important part of making a bent side mandolin even though it won't actually be used in the final instrument. The form is a set of plywood pieces used to hold the bent sides in place later when gluing them to the head and tail blocks.
I started by making the maple head and tail blocks that would give the finished mandolin much of its structure and connect the body to the neck. The simple neck to head block joint was made with a tenoning jig on the table saw.
I used an "inside" form design where the bent sides will be attached on the outside of the form using rubber bands. I used 3/4 inch birch plywood for the main body of the form. This type of plywood has many more plies and is a made from denser/ higher quality wood than standard pine plywood. This made for clean cuts and a better looking form. If there is any chance you will make another mandolin of the same design, higher quality plywood is definitely worth it.
Attaching the Head Block
I attached the head block with a sturdy 3/4 inch thick block secured with 2 screws in the block and two more in the form. This system is definitely a weak point in the form design, but I haven't come up with a better way to hold the head block in place. This method works, but it's clumsy to work with and isn't the most stable since the block can bend and therefore let the head block move (although only a little bit.)
Cutting It Out
I first glued on the paper template I would use to cut out the top profile of the form. Next I drilled out the corners of the tail block section using 1/4 inch holes. These holes prevent interference with the corners of the tail block when it is snugly fit into place. I did this before cutting out the area where the tail block would be held. This saved a lot of trouble compared with my last mandolin when I forgot this step and had improvise a way to clean up the corners so the tail block would fit. I also drilled a hole in the center of the form to accept a dowel. This dowel will later be used for securing rubber bands that will hold the sides in place. I cut out the form's top profile on the band saw and smoothed it with a drum sander then friction fit the tail block into its recess. With a template glued onto the tail block, I was able to shape the tail block.
Step 2: The Sides
I used a very basic bending iron setup to steam bend the sides. It consists of an iron pipe supported by two pieces of angle iron and tied down to a 2x3 with pipe clamps. The propane tank is supported by a loose clamp. This setup worked quite well for my purposes. It is quick to heat up and holds a steady temperature without too much fuss.
Bending the Sides
The sides were planed to a thickness of a little less than 1/8th of an inch before bending. To bend the sides, I first get the section I want to work with wet. I then rock the section back and forth on the iron until it gets very hot through to the opposite side of the wood. At that point the wood becomes flexible and can bend surprisingly easily with gentle even pressure. After a few seconds on the heat, the bottom side of the wood dries out, so I re-wet the wood then quickly reapply heat to keep the wood bendable.
I secured the sides onto the form to dry and cool. This was much easier with the center dowel system I used. It allows it to easily be a one person job to secure the sides as opposed to using large rubber bands stretched across the whole body. That method took at least two people, one to hold the side in place and the other to stretch the rubber band. With the center dowel and some small rubber bands, I could hold the side in place with one hand and stretched the rubber bands over the top side of the peg, around the rib, and then over the pegs other end sticking out of the forms bottom. I used small, light-duty rubber bands, but heavier ones may be more appropriate depending on how close your bends are to the shape of the form. With the rubber bands I used, even with quite a few, I still had to use a caul and clamps to secure the ends of the sides where there are sharp bends that the rubber bands couldn't pull tight. I used the piece I had cut from the head block in the same area since it was already the right shape. I also added a clamp down the center to hold the tail end tight to the tail block. I used the same clamping setup later for gluing the sides to the blocks.
Step 3: The Neck
The first step is to bandsaw the rough side profile using a paper template as a guide. I had to glue on ears to make the full width of the peghead even though it wouldnt be too wasteful to use a solid piece. To make the tuner holes, I first carefully centered the top paper template. I used this template to drill holes for tuning machines before cutting out the top profile for an easier job of holding the peghead down securely. To finish the neck (besides carving which is actually most labor intensive part of making the neck), I cut out the top profile and sanded it smooth.
Step 4: The Rim
Gluing on the Sides
I used the same system to glue the sides to the blocks as I did to hold them on after bending. I again had to use cauls to hold the sides securely to the head block and a long clamp to hold the bottom of the sides tight to the tail block. The rubber band system was especially helpful for positioning the sides accurately when gluing, even without an extra pair of hands. I used epoxy for this glue-up since the joints weren't pulling up as tight as I wanted. The joints were much better than on my last mandolin and wood glue would likely have worked, but I wanted to play it safe. I didn't get the joint between the side halves at the tail of the instrument as tight as I had wanted, but knew I would be covering that joint up with a piece of binding later.
Trimming the Sides
I used a low angle plane to carve the sides even with the mould and blocks. A thumb plane may also work for this task. I had already removed the block connecting the head block to the main form for easy access to the top of the sides. This is one of the times when this method of holding these parts together is a bit awkward. It would be better to keep the block in place and keep everything securely connected, but I had to remove it since it was in the way.
Finishing the Rim
At this point, I knocked the rim free of the mould and sanded the top and back surfaces flush with a belt sander while it was turned off. The form is now ready for use with the next mandolin I make with this pattern.
Step 5: The Top
The top is made of spruce and about 3/32 thick. To cut out the Sound holes, I used a paper template to locate and I cut out the sound holes. I started by drilling a hole, removing the majority of the material with a coping saw, then finishing with a wood rasp and needle files. These soundholes wound up being much closer to the edge than on the last mandolin. It took a lot more care and time to cut out the holes without breaking the top.
The braces were first cut out of a larger piece of spruce sold to be used in guitars. I notched the two braces together in the x pattern then glued them onto the top with wood glue. I used a flat board to clamp the top and braces flat while they glued.
Carving the Braces
I used a thumb plane to do the majority of the carving of the braces. The final height ended up being about 3/8ths of an inch at the center to essentially nothing at the tips. I didnt try to scallop the braces at all since my attempts on the last mandolin didnt work out to my satisfaction.
Step 6: The Back
Gluing the Joint
I glued the two halves of the back together with wood glue using the rig pictured. Once the glue was dry, I planed the top to its final thickness and cut out the top shape with plenty of overhang.
I made the center joint reinforcement out of one piece for this mandolin and glued it on first using a clamp at either end and a set of wood braces used to clamp the middle postion of the brace. I then notched and glued on the cross braces again using a board to keep everything flat while the glue dried. The ends of the lateral braces were carved down using a wood rasp.
I made up a custom label that matches the label that I glued in position under the bass side sound hole. It reads:
Mandolin No. 002
Built by Chris Williams, 2006
Step 7: Assembling the Body
Gluing on the Neck
Besides the awkward way I had to clamp the neck to the head bloc, this step went very smoothly. Although the joint wasn't as tight as I would have liked for strengths sake since I used wood glue, it did make the job easier and was still plenty strong. My last mandolin's joint was so tight I could't get it together with glue on it even though I was able to dry fit it.
I added the kerfed lining one side at a time securing each of the pieces with clothespins, then removed the excess lining using a sanding table.
Gluing on the Top and Back
I glued on the back and the top in one glue-up. To help me get even clamping pressure all the way around the top and back, I made more toy wheel, bolt and wing nut spool clamps for this glue up. I also added a number of other clamps to secure the head and tail block areas and fill in where needed.
Shaping the Fretboard
The fretboard was cut to it's final size using the belt sander and a paper template so I could use the fretboard's top profile to carve the neck. I brought the fretboard right to the line on the template. I was also able to add the inlayed position dots to the top of the fretboard.
Carving the Neck
I carved the neck down to its final dimension using the fretboard attached with small pins drilled into the top of the neck for the top profile. I also carved the heel of the neck to the correct size and created a smooth transition between the neck and body.
Step 8: Fretting
To install the frets, I started with the precut fret wire positioned at an angle to the fret board and gently taped it into place with a small ball peen hammer so the fret would catch the corner of the fret slot. From there, I carefully taped across to the unseated side until the entire fret was seated up to the tangs. To seat the frets the rest of the way, I started with strong blows to the two outside edges, working back and forth between the two sides until both sides were seated. This helps to avoid bending a concave curve into the fret wire, which could prevent the edges from seating all the way. From there it is just a matter of seating the center of the fret. The trickiest part of this process is keeping the hammer level to prevent damage to the fingerboard.
If a fret didn't seat all the way across, I removed it with the pair of pliers shown above. The small teeth allow the pliers to grab under the fret, so it can be pulled out. Being careful to not knock the little bits of wood that tear out when a fret was removed, I installed a new fret with the tangs in a different position from where they were on the old fret so the tangs have clean undamaged wood to grab onto.
Leveling the Frets
I leveled the frets with fine sand paper attached to a flat block of wood. To finish the frets, I re-rounded them with a crowning file and then sanded and buffed them to a shiny finish.
Filing the Frets
To dress the frets, I filed them the edges individually in order to give them an appealing angle and remove any sharp edges. I used a large file so that I could work with two frets at a time up higher on the fretboard which helped to protect the edge of the fretboard. On the lower frets, I used tape on the edges of the file to prevent them from plowing through the fretboards edge. To get the angle on the ends of the frets, I clamped the fretboard up on its edge and filed the angle using a block of wood clamped to the table as a guide so all the frets would be consistent.
Step 9: The Binding
The binding was made from two pieces of 0.080 inches thick by 1/4 inch tall rosewood purchased from Stewart-Macdonald. At 34.5 inches long, each of the two pieces used were long enough to make the top and and back binding each from one continuous piece of rosewood.
I routed the channel for the binding using a table router. I used a router bit with a bearing that rides on the mandolin's sides for a consistent offset. This method was very reliable, accurate and took no time to set up. I used a combination of two different bits to achieve the desired offset. I took the bearing from a 1/4 inch flush cut bit and the cutter from a 3/8ths inch bit which gave me a 1/16ths inch wide channel.
At the neck on the top side, I stopped just shy of the heel and then cleaned up the corner with a chisel. I went a bit too far at the neck on the back side and marked up the underside of the neck. These gouges luckily cleaned up of with a bit of recarving at the base of the neck. It really is only necessary to route to the heel on both the top and back since the button is going go there anyway.
Tail Binding Slot
I cut the slot for the tail trim that would cover the joint between the two halves of the sides on the table saw. I used a rig that was quickly improvised using a piece of plywood screwed onto a miter gauge and then clamped directly to the mandolin's body. One pass on the table saw was enough to make the 1/8th inch wide slot.
Unlike most buttons I've seen, this one extends beyond the neck's end and over the top of the sides. This is due to the very short heel section of the neck. The button looked strangely proportioned to me when I layed it out so it would only cover the top of the neck. I used chisels freehand to remove the wood from the button area and to smooth and flatten the final surface to accept the button.
Bending the Binding
I used the same rig to bend the binding as I used to bend the sides. I secured the binding to the body with large rubber bands while they dried and cooled.
Gluing on the Binding
I first had to carefully cut the top binding to length so that the ends would fit snugly flow into the neck. I left the back a bit long to be trimmed to size later. To secure the binding while the glue dried I used masking tape. This was very easy to do with only one person. It took a lot of tape and some care in how and how tightly the tape was secured so that the binding would be held firmly in place while drying. I added a bunch of rubber bands to the heel area where the binding was especially stubborn.
Trimming the Binding
Once the glue was dry, I planed down the top edge with a thumb plane. I sanded down the overhang on the sides using a spindle sander. Being careful to not take off too much material, I cut off the excess from the button ends of the binding for a tight fit with the button.
Using a paper template positioned with the binding as a guide, I drilled holes for the tailpiece pins. With the body clamped down securely on drill press, I drilled the four holes at least an inch deep each using an 1/8th inch brad point bit.
Attaching the Button
I glued on the oversized rosewood button using wood glue. I made the button by cutting a piece of rosewood slightly thick, then slowly sanded the profile using the actual heel of the neck as a guide. I could have made the button much closer to the correct size as it was very difficlut to par down without hurting the rest of the neck once glued in place.
Installing the Tail Binding
The tail end binding was glued with wood glue and held in place with masking tape to dry. I sanded the excess with the spindle sander again.
Step 10: Applying the Finish
I finished the mandolin using wipe-on-poly. Blue masking tape was very effective for covering the area where the fretboard would be glued and I didn't want cover with finish. I applied three coats with about three hours between the first and second coats as well as between the second and third coats. In-between coats I knocked down the shine and lightly smoothed the finish with 0000 steel wool. After the third coat, I waited at least 12 hours before going over the finish a final time using 0000 steel wool. You can also polish the finish with a varnish polish and a clean cloth if you would like an even higher level of shine.
Step 11: Setup
I started by making a rosewood blank just large enough to fit the bridge. I began to create the bridge's shape by first marking out the side profile of the bridge on the blank and then removing the majority of the unneeded material with a bandsaw. I used a microplane and a wood rasp to refine the side profile with the bridge clamped in a vise. Once I was satisfied with the side profile, I marked out the top profile. I used a rasp to cut the top profile by carving the sides so they curve up to the top layout lines. I hand sanded the bridge smooth then cut in the notches that would hold the strings in place over the bridge.
Gluing on the Fretboard
Since the pins were already installed to align the fingerboard, it was a very simple glue up using wood glue. I held the fretboard in place with a bunch of quick grip clamps all along the neck and over the body for even pressure.
I installed the tuners with the included hardware. This included small screws which I had to pre-drill for. These screws stop the tuners from spinning. With the strings in place, I could finish fitting the nut and adjust the height of the bridge.
The nut is often time consuming. It took me about an hour to make the one shown, and 30 minutes to ruin the first attempt. There is a very thin line between a low action that plays well, and a low action that causes the strings to buzz constantly. The only way to ensure a good result is to go slow, be patient and try not to push it too far. I've gotten caught a few times trying to make the action just a little lower, at which point I end up going too low and ruin the nut. Generally I just come prepared to do two nuts before I come up with one that I am happy with.
The unique tailpiece system I devised for the mandolin consists of four brass pins made from 1/8th inch round brass rod. I filed a groove into the side to position the strings, making sure not to leave any sharp edges.
Step 12: The Finished Mandolin
This mandolin sounds better than my first mandolin. It is much better when played with a pick than my other mandolin, but it still doesn't sound as good as my Kentucky f5 style mandolin. It sounds best when it is finger-picked, which makes for a sweeter sound than when played with a pick. The harsher tone of this mandolin when picked compared with traditional mandolins is likely due at least in part to the small pattern. At only 8.5 inches wide, it is much smaller than an f5 style mandolin which is about 10 inches wide. A larger pattern would likely allow for more bass response and volume.
I prefer the look of this mandolin over my last one as well. I like the rounder look of the body that results from a longer neck and a shorter overall mandolin. The proportions seem to work out better. My last mandolin ended up emphasizing the fact that it is much narrower than most mandolins. The biggest improvement in the look of this mandolin comes form the addition of the various pieces of trim. The addition of the inlayed position markers and the rosewood binding together make for a much more finished and professional looking piece. I still would like to add more trim to the next mandolin I make to pull the elements together even more effectively. I want to add binding to the peghead to match the trim on the body. I would also like to add a peg head inlay, likely of a simple symbol, my initials or maybe my last name.
That's enough rambling from me: I'll let the pictures speak their thousands of words!