Introduction: Hollow Bodied Practice Electric Cello
It's the sixth week of the UK lockdown due to Covid-19 and part of my time has been learning cello. I have had an acoustic cello for a few years now but not ever learned it properly. I've always used it in samples so only ever used it for simple pieces around a bar or two long, which I then used in a loop.
I had heard a solo cello piece I liked which turns out to be Bach Cello Suite No. 1 so I printed the music out ready to go.....well not completely ready go. My lack of music reading ability was a potential downfall but I have played guitar for a good number of years and I am able to read guitar tablature. Luckily my partner has a degree in music and can read it easily and she helped my transpose the cello music in to 'Cello Tablature' using 'fret positions'.
Always looking at new woodwork projects and have previously made an electric upright base and electric violin an electric cello was the next logical step (see my profile for these Instructables).
Additionally with being in lockdown I had to use offcuts and scraps I had already. This was part of the 'hollow bodied' reasoning as I could use a smallish single board resawn in to thinner boards to use for the body - I didn't have a solid board that size.
I also made as much as I could - the only bits I bought were the fine tuners, strings and tail gut. The rest was all made from scratch.
Neck - Sapele left over from when I got some building work done to my flat roof.
Body - Ash left over from a TV console I made a couple of years ago
Tail piece - Oak that could have been left over from anything!
Bridge and body extenders - Ash (same as body)
Pegs - Sapele (as neck)
End pin - hollow aluminium tube which was one of many, I think may have been from an old bed
Bolts - generally have loads of these
Piezo pickup - An old accoustic guitar surface mounted pick up that didn't surface mount anymore
Fine tuners These from eBay
Strings These from eBay
Tail gut This from eBay
Saws - table, mitre and band
Sanders - belt, oscillating bobbin and ROS
Routers - table and hand held
Drills - pillar and hand
Clamps - as many as possible
Step 1: Neck - Ash
I started with the neck by sketching the shape on a scrap piece of chipboard with the most important dimension being the length of the neck from the nut location to the end. Once I had roughly cut it out with the bandsaw I shaped it with a belt sander and a bobbin sander. I then cut the angle to the end of the neck template to around 10 degrees (which would eventually give me about the right height of the bridge in relation to the end of the fingerboard) - I did this knowing that it could be easily adjusted later.
The piece of timber I used was around 25mm (1in) thick so I needed to make two and glue them together to get the right width. I sketched around the template on to my bit of wood (the two sections just about fit on my bit of wood I had) and cut them out on the bandsaw. I the used a template router bit to make them both the same size before gluing and clamping them together.
Step 2: Fingerboard - Sapele
As I had played guitar for years and have my cello music transposed in to tablature I thought it would be a good idea to embed fret markers in to the cello fingerboard. This would help when getting used to the correct finger position and seeing where you are going wrong when practising. I took the measurements from playing one of the acoustic cello strings with a chromatic tuner app, marking on each note on the fingerboard with a pencil.
I started by cutting the fingerboard to the correct length and width on the table saw using a taper jig I set up by nailing a length of chipboard to the correct taper on the wood. I then set up the bandsaw to cut slightly wider that the kerf of my mitre saw and cut a load of fret inserts from a bit of wood I had left over from the neck. I then marked on the fret positions on the fingerboard and then set the mitre saw up to the angle of the taper and to cut less than full depth. I cut each fret position to the centreline of my marks.
Once the slots were all done I cut my fret markers to size and thinned them out with a plane until they were a good snug fit and glued them in to place.
The next step was to add the radius to the fingerboard. I still had my jig (Jig - see step 2) from my violin make and having measure it it was around 25mm (1in) longer than the fingerboard so I could use it but would have to attach the fingerboard from the underside rather than at each end. Once I had reconfigured the jig the radius was about right without the need for adjustment so I mounted the router over the jig and cut the fingerboard taking a lot of passes.
I then removed the jig, cleaned up the edges and hand sanded the fingerboard up to 240 grit.
Step 3: Finishing the Neck
Now the neck was completely dry I needed to give it a bit of shape so it felt nicer and looked better. I shaped the lower end of the neck (the bit that attaches to the body) with a taper, cut the main part to the same width as the fingerboard and tapered the peg box.
I decided to go for a hollow peg box as I like the look of them, so marked out the hole and drilled out as much of the hole as I could with fostner bits before finishing with a chisel.
I then rounded over the back of the neck with a hand held router and drilled out holes for the pegs.
Lastly I glued the fingerboard to the neck and clamped with loads of clamps using old socks to protect the fingerboard.
Step 4: Attach Body Sides to Neck
The body was made from a single piece of ash which I planned/jointed and resawed in to approx. 5mm (1/5in) thick planks. I then cut the wood to size making the sides around 40mm (1 3/4in)high, leaving the body to be as wide as I could, around 100mm (4in).
As the body was hollow I needed to extend the neck in length so I could glue enough of the sides of the body to make the bond strong enough. A longer neck would have been better but I didn't have any wood long enough for that. I therefore made a block which I screwed on with coach screws and then glued an extra bit on the end of this to make the gluing area quite large.
I then glued the body sides to the neck and waited for it to dry.
Once unclamped I could then work what shape I wanted the body and cut an end piece and some intermediate bits of wood to give a nice curve. I then drilled holes though these bits so the tail pin could move up and down freely through the body.
Step 5: Tailpiece
For the tailpiece I used a bit of scrap oak I had and sketched the shape on using the dimensions from my existing tail piece. I then cut it on the bandsaw, shaped the top and bottom with a belt sander and drilled a couple of holes to the bottom to house the tail gut. I then used a chisel to create a recess for the tail gut fasteners to screw up to.
I then marked on the location for the fine tuners, drilled and countersunk the holes followed by installing the tuners.
Step 6: End Pin Ends
I needed two ends for the end pin. The fist one would rest on the floor and the second would act as a stop on the other end inside the cello so you couldn't pull the end pin out.
I used a bit of yew I had left over from a project about 5 years ago which I mounted on a lathe and made these pieces from.
Step 7: Top of Body
I was now getting close to being able to glue the top panel on.
First I needed to make sure I had all the holes and nut inserts I need for all the bits I needed inside and outside the body.
The end block (nearest the floor) needed a central hole for the end pin, another for a bolt to be housed to lock the end pin and a third for the bolt to hold the tailpiece. I had an additional plywood piece close to the end which was to add stability to the end pin which needed a hole and another in the centre of the body (which would be below the bridge) which needed a hole for the end pin and a nut insert to the back so I could bolt a body extension to simulate the part of the cello that is held between the legs.
Once I was sure all the holes were done I glued the top to the sides and the intermediate part to the top. I used as many clamps I had on hand to hold it all together.
As this was drying I soldered a wing nut to the end of a bolt which will be used to lock the end pin in to position.
Step 8: Piezo Pick Up
I had an old surface mounted pick up from a guitar that had lost it's 'fixing sticky' years ago. I had taken it apart about a year ago so don't have photos of how it was - but from it I got a piezo pick up and a jack input. I used a section of old guitar cable and soldered them all together. I then used hot glue to keep everything in place and out of the way of the end pin.
Step 9: Back of Body
Now everything inside was done I could attach the back panel.
Before gluing I needed to determine the position of the insert nuts so I sawed the head of a bolt and gave the end a point using a drill and belt sander. I then inserted the bolt in to the insert nut and pressed the back panel in to position. This then marked where I needed to drill the holes.
I could then glue the back panel on and clamped the whole thing utilising the bolt holes and wood as additional clamps.
Step 10: Nut - Spalele
I then made the nut with sapele using the neck to get my measurements from. Once cut to size and sanded to profile I cut the grooves for the strings with a small file. I then glued it to the neck using only a small amount of glue so I could easily remove it later on if I needed to.
Step 11: Oiling
The main woodwork was now complete to I sanded all the unsanded parts to 180 grit and oiled the whole thing in danish oil. This really made the fret markers stand out.
Step 12: Bridge - Ash
This is the only part I didn't make. I got my partner to make this as she was getting a little bored in the lockdown and hadn't come up with anything to do that day!
She started off by taking measurements of the existing cello bridge and making a few sketches of possible designs. The bridge was then cut to size on the bandsaw and shaped on the belt sander.
The correct taper to the bridge should give you a right angle to the body on the lower side of the cello and a taper to the top.
The bottom the bridge was then cut, holes drilled and string channels filed.
Step 13: Pegs
To make the pegs I used rectangular pieces mounted on the lathe as one end of the peg needs to be flat. I turned a taper on one end of the block and left the other end flat. This end was then sanded to shape and size so it was easy and comfortable to turn.
The peg holes did need tapering though, so I turned an additional piece of wood to the same taper and applied some low grit sandpaper to it using CA glue and used this to make the holes tapered.
I could then put the pegs in to the holes, mark out the centre and drill holes at this position ready for the strings.
Step 14: Body Extenders
Now that the main body of the cello was complete I needed to add some bits to the back to help with stability. These parts are typically to the top of the body and around the same level as the bridge. I looked for some inspiration on the internet and really liked the look of the Yamaha electric cello so used the design of these parts quite closely for my cello.
I started of with the central extender that would lie behind the bridge. I stated by making the 'wings' by cutting out some nice shapes from some of the ash offcuts. I then needed to attach these to the cello body and came across an offcut which had had a curve cut in to it. The narrow bit was a bit narrow for the whole support bit so decided that curve would make a nice design feature. I cut the wood to width, mounted it on a lathe and turned the ends to the same diameter as one of my drill bits, so I could drill the wings and attach that way.
To stop of the whole thing from spinning I added a recess to the back which I cut with multiple passes on the mitre saw, before sanding a gluing.
The final bit was the top part with I made with a left over bit from the body with a couple of blocks behind it to bring it out from the body a bit. I then drilled a couple of holes below the neck for some insert nuts, drilled holes for the bolts and glued the extenders to the top part.
I then sanded and oiled both parts.
Step 15: Finished
The final step was to then put it all together. I first added the tailpiece and the C string only lightly tightening it so the bridge stayed in place. I then added the other strings before bringing them all up to full tension.
Once complete it was time to try it out. Luckily everything worked as intended, all the strings eventually stayed in tune (once everything stretched and moved) there was no buzz on the fingerboard, the pick up worked and all the fret markings were surprisingly accurate. When plugged in to a bass amplifier it sounds quite good, it could do with a bit more body but it is just a practice cello after all.
It can also be used unplugged which sounds a little tinny, but I imagine most electric cellos do unplugged, and it's quiet enough to play without disturbing the kids when they've gone to bed. Bonus!
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