Test recording of the custom bass

This morning I made a quick recording with the new bass and, rather than posting to soundcloud, as I normally would, decided to test out Windows Live Movie Maker to add a slideshow and some video.

The track was recorded direct into Reaper and Amplitube. Drums by EZ Drummer.

Custom bass is finished

The Danish oil had hardened nicely so it was on to assembly, wiring and set up.

First I gave the body and neck a good wipe down with a wax-based non-silicone polish. Note the tapered candle stuck through the hole in the top left of my bench. I leave that in there so that I can quickly swipe screws across it to lubricate them as I assemble.

This is the step I usually forget. I thread the earth strap wire through from the control cavity and fan out the strands to make a good contact with the base of the bridge.

All the hardware on.

I wire up the cavity. Simple passive volume and tone. The one variant I use is rather than putting the tone control across the input to the volume I put it across the output from the volume (aka “The Fezz Parker mod”). This reduces treble loss at low volumes. The lead from the pickup is far longer than I need but, raather than cropping it to length, I prefer to roll it up and tuck it away in the cavity, because I may want to reuse the pickup somewhere else later and I may be glad of the extra length of wire on it.

I break out one of my favourite little tools for testing continuity. Its a jack plug and short length of cable from a broken guitar lead. I can use my multimeter to clip one end to the lead’s shield and then go probing about touching all of the parts that should be grounded (pickup ground, pot backs, bridge) checking connectivity.

Now the wiring is complete I can get the strings on, do a rough initial set up (I like to let it settle for a week or two before doing a final setup) and there she is… COMPLETED!

It took me eight working days. The costs break down as follows;

Item Amount
Donor bass £53.20
Sapele timber for body £18.00
Musicman style pickup £14.99
Chrome bridge £17.99
Total £104.18

That’s what I call a result!

Preparing the bass for finishing

I’m into the final furlong now, and just need to get everything ready for final finish to go on.

The first step is to mark the final position of the bridge and drill the pilot holes for the screws to mount it to the body. I initially set the G string saddle to about 2/3 to 3/4 of its range of adjustment. Using the long rule, laid along the line of the thinnest string, I position the bridge so the G string saddle is exactly 17″ from the 12th fret (this bass has a 34″ scale length).

I mark the front edge of the bridge and then using my square and the centreline extend the mark.

Once the bridge is fixed in place, you generally have two axes of movement. You can move the saddles back and forward, or up and down. You can’t move them side to side. This is the one aspect of fastening down the bridge that you must get exact. To do this I run threads from bridge to nut, which makes it really easy to get this alignment perfect. I mark the top and bottom of the bridge.

I use a small bradawl to mark the exact centre of the outermost two holes. I drill the pilot holes, screw the bridge down using these two and then I can take my time and use both hands to accurately mark up and drill the remaining holes

I drilled the hole for the jack socket (the one scavenged from the Aria is a rather neat screw in barrel type).

After drilling the pilot holes for the strap buttons and pickup height adjustment/mounting screws the woodworking stage is complete. Onto preparation for finishing. I lightly dampen the body to raise the grain.

I usually regard this procedure as something simple and quick – but I realised I was missing an opportunity. On two of my recent builds (the Stratele and the Voodoo) I was disappointed that glue seepage round the neck pocket had interfered with the application of finish. As I was wetting down the body I noticed these marks where glue has seeped into the wood. I spent a few minutes with a Stanley knife blade and fine sandpaper getting rid of all traces. Before…

…and after.

I printed off the decal, shot a thin coat of nitro clear lacquer over the headstock face, applied the decal and then finished with two more coats of lacquer, all with drying time in between.

Once that had dried I removed the raised grain. This involves just getting rid of the ends of those torn fibres, and rather than sanding I think of it as more like wiping the body down with a piece of 320 grit paper in my hand.

And here she is after the first coat of finish.

It’ll get another heavy coat of warmed Danish oil this evening, and then tomorrow I’ll start applying thin coats using 600 grit wet & dry.

Routing the bass’ pickup cavity and gluing the neck joint

Despite my earlier pessimistic post, I did finally get a rain-free hour and I was able to get on with the final few woodworking jobs.

I first made a template for routing the pickups. I started by drilling the three 13mm holes for the pickup ears and then cut the shape out for the body of the pickup.

I tested it a couple of times on a piece of scrap MDF, making slight changes with a rasp and sandpaper, until I was happy with the fit.

I attached it to the bass body with double sided tape and routed it to 16mm deep, testing the fit at the point where I needed to remove the template to get to the final few millimeters.

I drilled the two holes into the control cavity for the pickup lead and bridge earth strap and then just had time to pack everything away before the rain returned.

After packing away I moved inside, checked the fit of the pickup, and then glued and clamped up the neck.

Tomorrow, should I get a gap in the weather, I need to drill the pilot holes for the strap buttons and bridge mounting screws, and then I’m on to sanding it down in preparation for the finish. Thankfully these two jobs don’t need much kit so I can quickly jump in and out to take advantage of any breaks in the weather. If all goes well I should get the first few coats of finish on tomorrow. This is my favourite part – where you first see the true colour and grain pattern of the wood.

Routing the control cavity and making a matching cover

Today I planned to get the control cavity for the bass finished, including cutting a matching cover from sapele. I used Inkscape to draw out the shape of the control cavity cover, printed that off twice and on one, drew the shape of the internal cavity freehand.

There were stuck to MDF and cut into templates.

For this job I needed three templates; one for the internal cavity, one for the control cavity cover, and one for the ledge the cavity cover sits on. The last of these two need to match as close as possible. I’m still searching for a way of using the router to create two exactly matching male/female templates, and I spent a couple of hours of experimenting with collets and straight cutting bits, with no success. More research required on this topic. Instead I used the offcut from cutting out the cover’s template, to make myself the template for the cover ledge. Not exact but close enough for me at this stage.

I select a piece of offcut sapele, and planed a couple of millimeters from a portion of it.

I attached the cover template, and routed round it to a depth slightly deeper than I would want for the cover.

I set up a fence on my band saw and sliced the sapele, just slightly thicker than I would need for the cover.

I attached the templates to the body and routed the cavity and cover ledge.

Rather than having a screw on cavity cover I decided to use neodymium button magnets, an idea which I’d seen used to great effect on the Musical Instrument Maker’s Forum (aka MIMF). The magnets are 6mm in diameter and 3mm thick. I drilled a 6mm hole at each corner. Initially these were just 3mm deep. I put pairs or magnets into each hole, put a drop of CA glue (aka superglue) on the top of each, then pressed the cover down. Once the three magnets were glued to the cover I could drill the holes to 6mm deep, put a dab of glue at the bottom of each, and then push in the magnets with a cocktail stick. NB: If you’re doing this then you need to pay attention to the polarity, because you want them to attract the magnets on the cover, rather than repelling.

One the glue holding the magnets had set, I sanded the top of the cover level with the body. I’m really happy with the result of this.

I drilled one small pilot hole through from the back of the cavity and then, making sure the relationship between the two looked OK, drilled the second one through from the front.

I used a 19mm spade bit to drill a “countersink” for each of the knobs. This means that the bottom edge of the knob can sit below the top face of the body, hiding the nut and washer securing the pot.

I drilled the 8mm hole for the pot shaft and then checked that it all fitted together neatly…

…before lightly sanding to round over the edge of the countersink.

Hopefully the pickup and bridge will arrive tomorrow, which means I can get the final routing completed, and glue up the neck. All that will be left to do is the final sanding, applying the Danish oil finish, assembly and set up.

Carving the body of the custom bass

When it comes time to carve wood I have found that the combination three different tools works very well for me. A flat and half-round rasp, a hand-drill with a spindle sanding drum loaded with 60 grit paper, and cabinet scrapers. The hand drill is great for removing large volumes of wood quite quickly. It is a bit of a crude and unwieldy beast so is not suited for fine work or in tight areas – particularly round the neck pocket where there are a couple of sharp fragile corners that would be easily damaged. For these areas I use the rasps. Once the wood is close to the shape I want I’ll smooth the area with the cabinet scraper, and then sandpaper and a sanding block.

The front view.

And the rear.

There is further work to do on the neck heel, but this will be after the neck is glued in place. I can’t glue the neck in before the pickup cavity is routed, so I’m waiting for that to arrive before I can make further progress.

Here are the pickup and bridge that I’ve ordered for it.

Good second day of progress on the custom bass

I started out today with the realisation that I didn’t like the body shape which I’d made a template for yesterday. So I started with making a new template.

I then roughly cut the blank to shape

Planed it to 41mm thick.

Attached the template with double side tape and routed round until the body was trimmed to shape.

I rounded over the back edge.

Made a template for the neck heel and routed the pocket in the body to a depth of 18mm.

To assist with the body carve I routed in steps in 1.5mm increments.

And then sanded them smooth.

Tomorrow I’ll order the bridge and pickup and while I wait for those to arrive I’ll rout out the control cavity and keep going on sanding the body into a smooth organic shape. Delighted with progress so far but I’m absolutely knackered now. Time for a shower and off to the pub to recuperate.

The next project: A custom 4 string bass

No sooner than I get the last project off the workbench and my fingers start itching to get going with the next one. This next project has many similarities to the last one. I’m going to take a cheap instrument I bought on eBay, build a new sapele body, upgrade the hardware and hopefully turn a sow’s ear into a silk purse. Some of the key design details on this one will be the extra long top horn, a carved top and reshaped headstock.

The instrument in question is an early 90s Aria Pro II Avante Series. After dismantling it, I lathered the neck and headstock in Nitromors to remove the heavy poly lacquer.

While that is soaking in, I mark a centre-line on a piece of MDF and the old body, line them up and then trace round with a pencil.

If I was just replicating the old shape, I would use a bottom bearing router cutter, but in this case I want to make changes to the shape of the two body horns; lengthening one and shortening the other.

I trim the MDF close to the line on the bandsaw.

And here’s the MDF template with the neck, just so I could make sure I was happy with the shape.

I’ll sleep on that and decide whether to make any changes (or perhaps even start again) tomorrow morning. If the weather is better tomorrow I’ll be breaking out the router and planing the pre-glued sapele body blank to thickness.