A 5-String Multiscale ‘Headless’ DIY Bass

[Dave Higham]

Hi everyone. I’ve been mostly a lurker lately but, as I recently finished a (nother) bass I thought I’d share it with you. And as the MIMF now allows ‘build’ threads (on n’arrête pas le progrès) I’ll show you (most of) how I did it.
I’ve made a few basses but each one has been totally different from the last because I don’t like making the same thing twice, I make them for fun, I make them for me (even though I’m a crap bassist) and I’m not interested in making Fender copies.
It has ‘fanned frets’ because I like the idea (but I’d never tried one) but not a very exaggerated fan at 33.5” to 35” scales as I don’t think my old fingers could cope with anything longer.
A ‘headless’ as I think that headless basses do look better with some sort of head (there are a few around) but the tuners are down at the blunt end.
It has a Glockenklang 3-band preamp and custom pickups by Aaron Armstrong, partly because they’re a non-standard shape and have covers to match the body wood and partly because of his reputation.
Just for the fun of it, I decided I’d try to make almost everything else myself.

By the way, this has been seen on a couple of other forums but some people only frequent one so I thought it was worth showing it here.
Here’s the plan.

I started with the tuners as I’d have looked pretty stupid if I got all the rest done and then made a cock-up of the tuners.
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 started by drilling some holes in a piece of brass bar. I draw all my plans in an Autocad clone 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).

The tuner block was milled from a piece of ebony. By the way, there’s no CNC involved here. This is milling the old fashioned way; counting the number of turns and divisions on the hand-wheels. 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. You’ll see what all the numerous holes are for as we go along, although I finished up with a few too many. By the way, I intentionally over-exposed 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.)
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.

You can enlarge the photos by clicking on them (in theory) and, if you have been, thanks for watching.

[Bob Francis]

Impressive! Please keep this thread alive through your build

[David King]

Dave, that's some very fine looking machine work you've done there. All I can say is if given the choice I would always use African blackwood over ebony for these types of parts. It's a bit denser, much stronger, it machines like a dream and never seems to move over time. That said if you're in a stable climate and your parts all have the same grain orientation you won't have much cause for worry.

[Hans Bezemer]

+1 for Bob's reply. Looking very nice!

[David Hawn]

Nice work,please keep the updates coming. I'm not ready to spend the money on DRO's for my mill so I do it the same as you. Your pre-planning ,component design and attention to detail really impresses me.

[Jason Rodgers]

Very clean work, indeed! Would phenolic work well for this application?

[David King]

Jason, aside from the smell, phenolic would work great.

[Dave Higham]

Thanks for the comments guys.
David, no doubt African blackwood would be a better choice, I suppose that's why it's a preferred wood for woodwind instruments, but I don't know where I'd be able to get it. I happen to have a rather large chunk of ebony so that's what I used.
Here's a further installment.

I made 5 friction pads from a different size of brass bar and glued them into the string anchor slots with thin CA. Then I drilled and countersunk holes for the fixing screws which fix the whole shebang to the body.
There’s probably 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 slide on the ebony.
There are 4 small neodymium magnets glued into 4 of the holes in the tuner block and its cover. They are slightly below the surface of the wood so that the cover is held firmly 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 ‘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. The final trimming, sanding, etc was done with the cover in place so you don’t see the join.

More later...

[Hans Bezemer]

I admire your eye for detail, great work and very educational.
Hans

[Barry Daniels]

I have made screw taps like that and they work well. The slot in the screw only needs to extend up to where the straight section of the screw shaft starts.

[Dave Higham]

You're right Barry. Although a longer slot leaves a bit more room for the dust to go.

I found these control knobs online at Axesrus in the UK. As my string spacing is 18mm I couldn’t use standard 5/8” diameter (19mm) knobs but these are only nominally 14mm diameter 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.

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

Here they are finished with their corresponding pieces of threaded rod. Sorry, no intermediate photos but it was just hacksaw, mill, drill, tap, files and belt sander. The threaded rods are 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.

[Dave Higham]

String anchors and knobs assembled. The 8 holes you can see are the ones surplus to requirements. As the magnets are very small I thought I might need more than the four you can see. I didn’t. I have enough trouble getting the cover off with just four!

And cover in place.

Thanks for looking.

[Jamie Unden]

That is just too cool!

[Jason Rodgers]

Say, that's just spiffy! Not being familiar with this sort of bridge, I wasn't sure how you'd be going about the tensioning action with the knobs. Very clean and simple. I look forward to seeing the rest of this instrument come together!

[Barry Daniels]

That is very nice machining work.

[Chris Richards]

Exceptional work.... You should be a watch maker! It's so nice to see such precision work and without a computer in sight, real engineering. On the point of fitting small screws I find that a touch of Vaseline on the thread reduces the torque required considerable and hence the risk of decapitating the screw, I'm not sure if it reduces the risk of splitting the wood at all though.

[Hans Bezemer]

Like I said before: I *really* admire your eye for detail. Keep the pictures comin'!
Great work.

[Dave Higham]

Thank you for the kind words.
I spent my working life as an engineering draughtsman (in the UK and France) and a large part of my time in the UK making prototypes and models for a boss for whom perfection was only just good enough. I think I might have quite liked to be a watchmaker, or a jeweller, or a cabinet maker, or a luthier...

On to the bridge. 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 via Ebay.
I actually bought some others from a Chinese seller which were a lot cheaper but they were rubbish; badly finished, corners polished off, saddles stuck in the slots, etc.

So first I need another piece of ebony, which means cutting another slice off this stonking great lump I mentioned earlier. I had to resort to traditional methods for this as I don’t have anything else that would cut it. Here’s an action shot.

After cleaning up and squaring 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. I did it like this because, once I'd got the vice aligned correctly with the table, I didn't want to move it again.

And here it is with the slots milled, the ends trimmed, the corners radiused and the saddles in place. The colours look a bit weird in these photos. The streaks in the ebony look mauve on my monitor, but they’re grey really and with a bit of finish they’ll turn brown. I prefer ebony to have a bit of colour in it; makes it look less like black plastic.

[Dave Higham]

Now for the body.
I bought the top wood about 7 or 8 years ago from Larry Davis 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 want 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 shape cut out on the band saw leaving about 2mm for trimming the final profile. As you can see here the cavities vary in depth to allow for the carving on the outside of the body. (Hoping I got my calculations right!). I never took a photo of the master template which had two holes in it with a brass bush pressed into each hole. The back and front of the body and just about all of the other routing templates that followed had these two holes transferred to them so that everything aligned as it should. You can see the two 5mm holes in the back and front here. One of them became a neck bolt hole and the other a potentiometer hole.

So, aligning the back and front with a 5mm brass rod in each hole, I glued them together using the usual forest of clamps (just about every one I own).

And this was the result.

[Hans Bezemer]

You're making some good progress!