A 5-String, Multi-Scale, Almost Headless Bass

[Dave Higham]

I haven’t anything very interesting on the go at the moment, so I thought I’d rake up another old project.

I made this instrument 10 years ago and at the time it was the most ambitious project I’d undertaken. I’d made a few basses, each one different from the last and this one would again be different from the others in several ways.

I decided to make a multi-scale because I liked the idea (although I’d never tried one).

A ‘hybrid’ headless because I thought that headless basses don’t look quite so ‘broken’ with some sort of head.

A Glockenklang 3-band preamp  because that’s what Sheldon Dingwall was using at the time and custom pickups by Aaron Armstrong, partly because they’d be a non-standard shape with covers to match the body wood and partly because of his reputation. (We do know who Aaron Armstrong is don’t we?)

And just for the fun of it, I decided to try to make almost everything else myself.

This is what it I intended it to look like.

 

I started with the tuners as I thought I’d look pretty stupid if I got all the rest done and then made a cock-up of the tuners. As you can see, the tuner block and the bridge are separate items.

I have a small metalworking lathe and milling machine (model-making size really) but I don’t know where to buy blocks of aluminium in my neck of the woods or where to get things plated or anodized so I decided to make the tuner block from ebony with small brass and steel components where I thought they’d be needed.

I starting by drilling some holes in a piece of brass bar. I draw all my plans in 2D CAD  and often print out a plan of the piece I’m working on and stick it to the piece in question. In this case it was just as a safety check so that I didn’t wind the table along a millimetre too far at some point (easy to do).

Here’s a very fuzzy photo of the brass bar with its holes drilled and countersunk and the ends trimmed and a radius on the corners.

The tuner block was milled from a piece of ebony. No CNC involved, just milling the old fashioned way; counting the number of turns and divisions on the hand-wheels and checking everything twice. There are no photos of chips flying off  the cutter as I was rather concentrated on what I was doing and didn’t think about taking any. The five large slots are where the string anchors will slide.

Here’s a view from the other side. You’ll see what all the numerous holes are for as we go along. I had to intentionally over-expose some of the photos as at normal exposures you can't see any detail in the ebony components. (At least you can't on my monitor.). The colours are sometimes a bit weird also as this was before I discovered the colour correction feature on my camera.

Although this looks like the last-but-one photo, if you look carefully you’ll see that four of the holes have little brass locating pins in them for the cover.

And here’s the cover with its corresponding holes.

More later.

[Dave Higham]

For want of a better description I’ll call these friction pads, made from a different size of brass bar.

This is where they go. I thought there would probably be some friction between the string anchors and the bottom of their slots. How much should depend on the string angles, so that’s the reason for these pads. The other brass bar fits over the slots so there are bearing surfaces above and below the anchors. There are no lateral forces on the anchors to speak of so they’ll slide on the ebony.

Here the pads have been glued in place by wicking a drop of thin CA around each one and holes drilled and countersunk for the screws which will fix the whole shebang to the body.

8 neodymium magnets are glued into the block and the cover with thin CA to hold the cover in place. They were already a force fit in the holes so they shouldn’t move. They are slightly below the surface of the wood so that the cover is held shut and won’t rattle.

I now installed the brass cover plate which is held in position by small (2.5mm) woodscrews. I know them as chipboard screws but they seem to be used for everything these days.

Inserting screws into ebony isn’t quite as straightforward as it is with softer timbers. I did some trials with ebony scraps and even with a pilot hole larger than the core diameter of the screw I was afraid that I might split the ebony. You can see that with all those slots and holes it does look a bit fragile.

So I made a primitive tap. Using a Dremel with a little Dremel cut-off disc I ground a groove in one of the screws. Then I did another trial in an ebony off-cut drilling a hole just bigger than the screw core diameter and gently screwed my makeshift ‘tap’ into it and out again. Then I fitted a normal screw and tightened it not-too-hard so as not to strip the threads. Here’s the ‘tap’.

The block with the cover in place, the ends trimmed to length and a radius on the corners. (Is there such a word as ‘radiused’? The spell-checker doesn’t like it.)

[Bizman62]

4 minutes ago, Dave Higham said:

(Is there such a word as ‘radiused’? The spell-checker doesn’t like it.)

It's a word I've learned from various luthiery videos. So if it isn't a word yet, it will be.

When I started to build guitars and watch related videos, neither the printed nor the online dictionaries seemed to know the word "luthier". It now can be found in Wikidictionary, since 2020. Languages evolve!

[curtisa]

Better than 'radiusifiedinated' I suppose?

[Alucard0811]

If this is going to be just a fraction of the worksmaship you showed with the acoustics, this is going to be a hell of a ride.

 

will follow this one closely.

[Dave Higham]

I found these control knobs online at Axesrus in the UK. As my string spacing was to be 18mm I couldn’t use standard 5/8” dia. (19mm) knobs but these are only nominally 14mm dia. I put them in my little lathe and drilled the holes out to 8mm diameter.

Then I made some inserts from 8mm brass bar with a 3mm threaded hole.

Drilling a shallow hole as a location for the Allen screw in the knob. If the Allen screw loosens the knob will still turn the insert. I could ‘glue’ the inserts in with Loctite bearing seal or threadlock but I’d rather be able to get them out again if I need to.

Here’s the full set.

[Dave Higham]

Starting on the string anchors, made from mild steel bar. The only stuff I could find easily in the DIY stores is this hot-rolled stuff so I had a bit of machining and filing to do.

String anchors finished. Sorry, no intermediate photos but it was just hacksaw, mill, drill, tap, files and belt sander.

Here they are with their corresponding pieces of threaded rod. Stainless steel as it happens.

Threaded rods fitted using threadlock. Again the only one I could find locally. The red stuff would have been better but I think this should be OK. If they unscrew I’ll have to try to get some red (or solder them).

Finally here are all the bits and pieces together with 5 black nylon washers to go between the knobs and the ebony block.

String anchors and knobs assembled.

And cover in place.

[Nicco]

Bloody hell. That's gorgeous! 

[Crusader]

^ Agree with above, man I want to get a lathe!

[Bizman62]

^^ those.

[Charlie H 72]

Wow, this tailpiece is really expanding my idea of what parts can be homemade. exciting stuff - I’ve already gone over the post a few times to soak in the details. The string anchors- how do they interface w the strings? I’d imagine the way you have shown the tailpiece that they would want to pop out so I must be missing something.

[Dave Higham]

7 hours ago, Charlie H 72 said:

The string anchors- how do they interface w the strings?

When installing the strings, the ferrules are inserted into the anchors and the anchors withdrawn until half the ferrule is inside the housing. The other ends of the strings are then fixed. The strings are then brought up to tension, at which point the anchors are completely enclosed (like the one on the right hand end).

[mistermikev]

11 hours ago, Dave Higham said:

When installing the strings, the ferrules are inserted into the anchors and the anchors withdrawn until half the ferrule is inside the housing. The other ends of the strings are then fixed. The strings are then brought up to tension, at which point the anchors are completely enclosed (like the one on the right hand end).

at first... I was wondering... and due to your explanation... I realize there is going to be another part (where intonnation will happen) - thank you for that... much less confused now lol!  some lovely work there.

[Dave Higham]

Yes, I call the bit where the intonation takes place the bridge and I decided to make that next. I bought these cheap ABM copies on eBay. Ok, they’re made from what we used to call ‘monkey-metal’ (zinc alloy) not bell brass but I’m only going to use the saddles and they’re actually quite nicely made and finished. They came from ‘Bezdez’ in Canada.

So first I need another piece of ebony, which means cutting another slice off this stonking great lump. Here’s an action shot.

Then I cleaned up and squared the four faces on the belt sander.

Here’s the bridge block screwed to another piece of wood at the correct angle for milling the slots.

And here it is with the slots milled, the ends trimmed and the corners radiused.

Top edge radiused

And this is what it should look like with the saddles in place. The grey streaks in the ebony will probably turn brown under finish.

 

[Dave Higham]

So now I needed to make a start on the body.

I’d had the top wood for about 7 or 8 years but got distracted by another project each time I should have started on it. It’s figured maple and about  7/8” thick.

 

The other body wood is alder from a French supplier and is in one piece. The alder was about 1”1/4 thick so I had to make a router sled to take it down to 7/8” but I’m afraid I didn’t take any photos of that.

 

As half the body is maple and I wanted to keep the weight down as much as possible I decided to hollow it out wherever possible. So here I am, making a start with a Forstner bit.

Then cleaning up with the router.

Here the cavities have all been routed.

And the body profile cut out leaving about 2 to 3 mm extra all round. The cavities vary in depth to allow for the carving on the outside of the body.

Here’s a photo of just about every clamp I owned at the time.

And this is what it looked like when the clamps came off.

[mistermikev]

so very creative idea about the saddles.  those saddles look like they would fit the ghost piezo saddles.  is that height adjust block removable?

[Dave Higham]

4 hours ago, mistermikev said:

is that height adjust block removable?

Yes, it is.

[Alucard0811]

Thats some nice work, and the wood selection *chefs kiss*. 

 

Cant wait to see it come together and get some finish on this beauty.

[Dave Higham]

I took one of the off-cuts and sliced it up. These are some of the slices.

Here’s a book-matched pair. After jointing, gluing up, sanding and wiping with alcohol to show up the figure, this is what it looked like.

Now I could go back and finish the tuner block cover.

Although I don’t have any photos of the process, I milled out a shallow recess in the cover about 1.5mm deep and glued in a book-matched piece of the maple body wood.

The final operation was to plane and sand a 3mm radius round the top edge of the cover.

Pickup covers next.

 

[JGTay]

That is some next level custom part work. Fantastic job.

[Bizman62]

31 minutes ago, JGTay said:

next level custom part work

I'd even call that a couple of levels higher than that. What is the superlative for mind-blowing? Mindblowingest?

[Dave Higham]

The first step was to cut another piece off that lump of ebony and transform this into 4 strips each with a small rebate along one edge.

Each strip was cut into over-size lengths and the ends bevelled one corner at a time to create a mitre joint.

To make sure my mitred corners were accurate I checked them on a print of the drawing. I designed the pickups to follow the progression of the fanned frets and the ends are parallel to the outer strings; so, not only are the pickups different lengths, none of the corners have the same angle. Once the first corner was done, I started on the next corner but leaving the length over-size. Once I got the angle right I could then reduce the length of the piece between first and second corners to its correct length and start on the third corner, etc., etc.

I then simply super-glued the pieces together. If you have perfectly mating surfaces it makes a surprisingly strong joint. I know this because of the effort it took to get one apart when I got the angle wrong.

Here are the two frames glued up.

[Bizman62]

I just keep shaking my head in awe.

[Dave Higham]

5 hours ago, Bizman62 said:

I just keep shaking my head in awe.

Thanks for the kind words Biz.

Someone said "Building guitars isn't rocket science, it's harder than that". But it isn't really. It's mostly just cutting bits of wood up and gluing them together.

[Nicco]

I feel like you're doing yourself a disservice there! Ha ha.

Lovely work as always. Looking forward to the next chapter.