CAD MODEL
I settled on an instrument which had 12 strings (C, C#, D, D#, E, F, F#, G, G#, A, A#, B) and two octave shifts which would allow the chordophone to have a total of 36 notes! How grand!
After many, many hours sitting infront of the computer, pulling my hair out and grinding my teeth. I produced this CAD model:
I initially started designing something with an enclosed acrylic body. This proved to take up a LOT of material and eventually I decided to make something more along the lines of my last prototype. The result was a completely open model which meant the electric pickup would play a much larger role than I first assumed. I had not thought about the pickup system much at all up to this point. Because there were so many strings spaced quite a distance apart, I thought perhaps I'd use a microphone instead of a magnetic or piezo pickup. And while I realised I needed to put more thought into the electronics, I didn't. And I set off to the workshop to begin manufacturing my Harpsichord.
Mac helped me a lot at this stage, with all his woodworking bias intact, he suggested corian would not be a viable material to use. This threw me off a little as I had made all the pieces under the presumption that they would be made from strong, rigid, corian. To make it out of another material was daunting.
I called up several corian suppliers and found that it would cost be around $1000 dollars to get enough corian to even make a start. I'm not kidding, I don't know who told me it was cheap but it really wasn't. I knew these supply stores would have what I needed in their waste bin from all the off cuts but I wasn't about to go scrounging around for freebies.
So, what material should I substitute in? Timber was the obvious choice. workable, cheap and comes in large amounts. I headed down to Bunnings and Otto's to find something viable. The base needed to be at least 30mm thick and all the other components were 12mm. This threw a spanner in the works because the only wood that comes in 12mm was ply and MDF. And I wasn't going to settle for that crap. Bunnings had a good selection of 30mm thick laminated boards big enough for the base priced at $99 but the nice, pretty looking timber only came in that size. Otto's didnt have any large laminated boards on offer. So... I had to settle for pine. Pine was cheap and came in 18mm boards aswell.
I had to thickness this 18mm board down to 12mm before it went onto the cnc machine. But I had to slice it in two before it would even fit into the thicknesser. But that wasn't a huge issue. After a couple days, I had my CNC'd pine.
The above image shows a failure of the CNC milling or (more likely) the failure to prepare the file properly. The right side of the base was missing. Not too big of an issue, but I needed the slots to be 12.3mm wide to fit the 12mm components comfortably. I glued an extra length of wood to the side and cut it down to shape.
The right hand slots were now a little too tight but i widened them with a file and elbow grease. Standing back, I realised this instrument was going to be a monster, enormous and overt. Perfect.
The perimeter was chamfered using a router. I was thrilled with the result and had a lot of fun using the tool.
The jacks failed twice unfortunately. First in pine and then again with ply which i shamefully turned to so as to avoid thicknessing the pine again. A couple of pine parts snapped which i was cleaning them up, so I used ply to replace them thinking it would be a lot stronger, which I think it was. The jacks just didn't want to work however. They had to be 8mm thick, not 12, which probably put the CNC mill under quite a bit of stress. My solution? laser cut the parts! But wait, the laser cutter only cuts up to 6mm... I'd need to cut something 4mm thick twice and glue them together.
Nothing comes in 4mm Luke.
Ahh! But MDF comes in 6mm! Toby was a lad and reluctantly thicknessed the MDF to 4mm (the thicknesser doesn't like ply and MDF because the glue fucks up the blades). The laser cut worked well and I set off gluing together the 24 parts to make the 12 jacks.
Every wooden component was sanded with 240 grit sand paper ready top be stained and varnished. I set up shop in my shed and spent HOURS painting these things with a paintbrush.
I was actually horrified by the results. I don't have any good photos, but the brush strokes were exceedingly visible and the parts had an almost fake tan look about them. I hate fake tan. I learned afterwards, that the best way to apply a stain is to use a wet rag. Well I cut my losses and used this process for the next two coats, and the end result wasn't beautiful, but it was acceptable.
After being eaten alive by mosquitoes during the first coat, I lit some of these bad boys up to shield me from the dark and terrifying night.
No questions please.
The Jacks all needed a 5mm hole through them for a bolt which the tongue would pivot about. And almost everything in this design needs to be done TWELVE BLOODY TIMES. No matter. I made my first few jigs to help me with a few of the processes.
This little block tightly fit in the space of the jack to ensure the drill press didn't snap the jack.
SNAP. Okay, not a perfect jig but we'll manage.
The use of a clamp ensured the MDF wouldn't split along the glued edge when the drilled entered. This worked without a hitch for the following 10 jacks, drilling a hole in precisely the correct spot.
Next, I had to get rid of these awful burnt edges, a product of using the laser cutter. The few lighter coloured jacks were hand sanded down and probably took me 40 minutes just to do these four.
The disc sander put my sanding efforts to shame in about 8 minutes flat.
The tuning pegs were lathed from a 10mm steel round and filed to have two flat faces for the string to grip to as it was tensioned.
A hacksaw was used to cut a groove so the pegs could be turned using a flat head screwdriver.
These pieces were situated at the front of the instrument for the string to run over (called the bridge). I needed 24 these. 12 at the front and 12 at the rear (called the nut on a guitar although there's only one piece for a guitar nut, not 12).
It was at this point that I knew I had to decide on a pickup system. I voiced my concerned to Gilly and Jack, who were both also making chordophones, and told them how I had a wide distance from leftmost string to rightmost. They showed me an under saddle pickup.
These work by sitting underneath the saddle which holds the nut on a guitar. The strings vibrate on the nut and the pickup sends the frequency to the amp. This was actually perfect for my needs. I ordered two of them, and then a third later on when I realised 2 wasn't enough.
I made a jig to help me cut grooves in the same spot for 12 of these to ensure I had a horizontal slot for the pickups to fit into.
The weren't perfectly straight, resulting in some pieces contacting the pickup more than others, but it was the best method I could come up with.
I made the tops for the sharp keys (C#, D#, etc) from two pieces of 6mm acrylic glued together. Using the disc sander at 15 degrees, I was left with a reasonably satisfying result. They all had to be sanded with 800 grit sandpaper. But then.... Tragedy.
The can of stain/varnish opened in my car. It was contained within a plastic bag, but the sharps were soaked. After re-sanding them I was left with a moderately decent result, even though some of the stain had soaked in between the glued together halves.
Bit o' Clear coatin'
I only have a picture of me disc sanding the balance pins, which were made from 6mm steel rounds, but I should mention I burnt my thumb INSTANTLY after this photo was taken.
Steel gets hot on this machine.
And that about does it for the component preparation. The next step was assembly! The easy part, right? RIGHT?!
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