CityCaster-006

A new Bass project! 

A friend of mine asked me to build him a custom bass, combining several bass elements he likes from other instruments:

• The body is inspired from a Sterling

• The Neck is very close to a JazzBass and inspired from a JamesTrussart Bass

• The head is inspired from a Carvin Bass

I worked on the design and together, we agreed on small modifications to match his vision. My friend selected and worked on a city map  modeling the northern African city of Timgad, a Roman city in the Aurès Mountains of Algeria. This is in souvenir of a project he worked on when studying architecture, and a common friend.

The basic shape is shown below, and the instrument will have Gotoh tuners and bridge, and JazzBass pickups with an active preamp with PU blend, volume and 3-band EQ.

Using Aspire, I created the 3D shapes for the body, neck and fretboard. Modifications were brought to the body to match the number of controls and the bridge. The neck heel imposed a slight adjustment of the body as well. In terms of woods, we settled for iroko fretboard with boxwood inlays on the side and top, Alder for the body and mapple for the neck. We sourced the wood at Delta-bois; They have a nice selection of woods for music instruments, not far from where I live.

Let's work on wood!

While I was waiting for the wood we ordered, I worked on the fretboard as I had the iroko and boxwood readily available. I started with the boxwood inlays, making about 30 of them (10 were needed); They look like a wide comb before being separated using my bandsaw. The fretboard is 6mm thick, and shows a curvature of 410mm radius. The inlays pockets are carved on the left side to accept their boxwood counterparts before the fretboard top is shaped and the fretboard is finally cut.

The neck

I then worked on shaping the neck out of a curly mapple blank (size 100x70x27) and this went well up to a certain point... I unfortunately calculated my carving paths (for the curve at the back of the neck) for a Ø4mm bit and used an 8mm bit... Of course this resulted in basically unwanted and long scratches/scars about 2mm deep on each sides of the neck, forcing me to sand them later on and the result is a neck which is probably 1 to 2 mm thinner than expected... As I don't know what the behavior of the junction for the neck to head part will be under string tension, I ordered a new blank and will be ready to redo the neck if needed. As it is now, it looks fragile to me, but I need to validate this with actual strings and getting the feedback from the actual user of the instrument. Because after all, the neck is just gorgeous!

And the body...

With my sad experience with the neck, I did double/triple check my settings and choice of bits for making the body. I started with a 45mm thick Alder blank and was careful in setting my options for carving the different parts. It all wend very well and after a few hours of CNC carving (took a full day nevertheless), I had a nice body, still attached to its blank and ready to go under the laser...
I took my time too in setting the big slab of carved wood on the laser bed, ensuring my laser engraving would fit exactly where it should be. Once launched, there's no fixing or turning back! I made a few tests on a corner of the blank to ensure my laser carve would be  approx. 3mm deep. I ended up at 2.81... close enough.
The laser part took from 10:35am to almost 6pm... And again this time I was luck to not experience a mains failure... Thanks EDF :-)
The rsult of the laser engraving is very nice, and this promises a beautiful instrument...

More body work...

I rounded the body on both faces all around (or pretty much) using a special bit and my hand router. This is much faster and a rather simple operation that can be done by hand. And I started sanding at 80 grit, 120, 180, 240, and finally 320 for the body. I sprayed the body with clean water to raise the wood grain and let it dry. I then sanded again with 240 and 320, ensuring there were no sharp edge and no tooling marks... After drilling holes for the PU wires and jack output,  I could finally apply a first coat of OSMO Poly-X semi-satin oil. The wood is revealing under the oil, with a honey color that looks  gorgeous!

Dry fit

I took the time to test a few things before applying the first coat of oil to the body and neck... I also had (of course) fretted the neck, leveled the frets and polished them. The dry fitting of the neck on the body is just perfect, and setting the Gotoh bridge in its expected position, I could measure about 1.8mm from bottom of the string to 12th fret, and I have a good 1mm to play with at the bridge, so all should be fine.
Applying a coat of oil to the neck reveals the curly nature of the maple neck... beautiful!

The bass body and neck have now received 7 coats of Osmo Poly-X oil, with a light sanding between coats (320 for the first 3 coats and 400 after) and they are now ready for assembly! Here they are, hanging a few days prior to this and alongside a new body (Lyon engraved) for exchanging twith he body of CityCaster #004, as the owner is from Lyon and prefers that city over London :-).

7 coats later...

After lots of OSMO Poly-X coats, she's finally ready for assembly. No issue on mounting the neck, strings and electronics. All this went smoothly. I worked on the nut and adjusted the intonation. All good. A string retainer for the G string will be necessary/added as the string could jump out of the nut when played hard. It will sound better anyways with a retainer forcing a string break angle after the nut as we typically can find on P-Bass guitars. But this instrument is really good lookin' :-D