A 3d printed headless bass ...

[SpondonBassed]

That's looking smart.

[Richard R]

Very impressed!

 

[Stub Mandrel]

11 hours ago, rwillett said:

 

After a lot of fiddling about with small wires, tinning, trimming, soldering, frustration with all the previous, I finally got the electrics finished and in. Blow me down with a feather but it worked first time.

 

Volume on two pots and tone (well some version of tone) on the third pot.

 

Pull out the first pot and it puts the two pickups into series mode and turns off the 2nd volume pot,the volume goes down though, which is a bit of a surprise, I wonder if I have the two pickups out of sync. Now one advantage of the way I've wired it, is that its a 10 min job to change what is the bridge wire and which is the hot wire for each pickup.  That may be the solution (or not).

 

Anyway, I originally used a NUIX headphone amp plugged into the guitar to check it works. Thats a mistake as the NUIX bass amps simulators leave a lot to be desired and it wasn't clear where the tone was. Plugging back into Logic Pro tidied everything up and I could breathe a sigh of relief as it sounded well. The differences are subtle though, the neck pickup isn't vastly different to the bridge and the tone control has a simple 0.047uF capacitor and the change in tone is there, but is very small. Something to look and think about.

 

Strap buttons are on. It plays quite well (given that there are suspension bridge cables in use for strings). Needs some careful setup now.

 

 

Next steps are dismantle it all, glue to the major sections together for a more strength, copper tape all of the insides to reduce hum, tidy up the wiring inside the control panel, take a Dremel to little bits of the aluminium backbone to get them flush to the body, polish and lacquer the aluminium, reassemble and then learn how to really set it up.

 

 

Congratulations!

[rwillett]

Thanks.

 

I actually put a strap on it for the first time yesterday and its very well balanced. I'd like to say its through careful design, extensive use of complex maths and constant iteration of various materials... but lets be honest, I guessed.

 

Sadly its all going to be dismantled over the weekend, tidied up and glued (where appropriate). Its currently held together by screws and pins. Thats by design, and is significantly stronger than I expected. You could gig with it as is, but I do need to do the finishing bits that will annoy me, making sure the aluminium backbone curves perfectly match the printed curves, copper lining to ensure no hum. Surprisingly in my home office, it doesn't hum, no idea why as the amount of electronics here is approaching black hole density. So thats a nice bonus, but lets do the job properly, sort out the little bits, as I want to be able to say "its finished".

 

Rob

[Henrythe8]

Wow. Impressed from beginning to end. 
A question though, why would you want to glue the parts ? I would have thought that the design with the 3D printer would also give the possibility to change some parts and give it another look ? 

[rwillett]

4 hours ago, Henrythe8 said:

Wow. Impressed from beginning to end. 
A question though, why would you want to glue the parts ? I would have thought that the design with the 3D printer would also give the possibility to change some parts and give it another look ? 

 

@Henrythe8

 

This all comes back to a fundamental part of 3d printing, the size of the print bed. Most printers are around 220x220mm in width and depth and around 200-250 in vertical height. There are printers that are 300x300 and a few that are even bigger.

 

The larger the print bed, the more chance you have of the following issues:

 

1. Print bed not heating evenly. The filament needs a hot bed to adhere to, PLA filement needs circa 60C, PETG filament around 90C. Its harder work (but not impossible) to keep all the print bed at the right temperature.

 

2. The frame that holds the extruder head and moves it around the print bed needs to be solid. We work to 0.07mm on the latest printers. The frame has to hold that head exactly in position, for every hour, for every day. No exceptions. The bigger the frame, the more difficult that is.

 

So the compromise is that most decent printers for home use have a print bed around 200-250 in each dimension. I know that you can get 300x300mm printers, but that just kicks the can down the road a tiny bit.

 

So the most we can print is around 220x220mm, we can fiddle that a little by printing on the diagonal, remember Pythagorus?

 

Most guitars and bass's are bigger than 220x220mm, though none are 200mm taller (so far). This means that whatever guitar (bass or six string) you want to print has to be done in pieces, no way round that easily (thats a white lie and I'll cover that later).

 

So you print in pieces, no choice there, which means you have to join the pieces together. This 'join' could be:

 

1. A clip type joint, push together and it clicks into place. Works for something, but not sure it would on a guitar. Never tried to be honest, but nothing says its going to be a success

 

2. We screw/bolt pieces together. I've done that on my very first 3d printed guitar and it works very well. Very solid. Downsides, its hard work to hide the nuts and bolts if you have a open type of guitar, which mine are. I had a lot of embedded nuts in the design, but that means that your printing is hard work as you have to pause the print at certain times to insert hardware. Since some of the prints were 30-40 hours (on my old printer), this meant being woken up at 03:30 to put nuts in and then resuming the print. 

 

3. We glue stuff together. I was originally 100% against this, but after experimenting with an awful lot of glues, I found a cheap glue that works brilliantly on PLA and PETG by 'welding' them together. Forget superglues as they do not work reliably. I have 6-8 different superglues I tried out as well as various expoxy resins. The best was Floplast from a plumbers merchants, £9 for 250ml which lasts about six months. The problem with glueing is that you have to get the two parts to match perfectly. No big deal it things are a mm out on a plumbing pipe join, massive issue on a guitar. So I changed the design to put pins to locate the pieces. You can see the three round pin holes on the end of the top left piece below. These are 4mm in diameter, easy to print and work really, really well. 

 

 

Here's the top middle piece that joins to the one above.

 

 

This works so well, that I built the bass without any glue at all, just pins and screws to the backbone, and it plays pretty well. However there is a little movement, perhaps 0.2mm between the pieces, so I will glue it together to fix that. That was always the plan, use glue, to be honest. Once glued, the pieces are really welded and if I do a stress test in the pieces, which I have done as part of the glue test. Once glued (welded really), the glue is stronger than the component. It does need quite a lot of force to break it and the glued bits don't break.

 

There are a lot of challenges about fit lines and getting them as tight as possible. That's another story and a lot of work to make things flush. Not quite as easy as it sounds

 

In answer to your second point, changing the "artistic" design (I paraphrase), is pretty easy to do. This was designed in from the start. So here's a very wild Explorer design that I thought about as a proof of concept. Probably take a week or two to design and print as I have real work to do, but no real problem, as the hard work has already been done for the core of the guitar. A firebird would be slightly less radical and a bit quicker. It should just be a matter of unassembly of the current body and putting the new one on.  There's probably some design compromises around the neck area as that has shaped aluminium and so a few cm each side of the neck would stay and the design would have to match that.  So an SG type double cutaway wouldn't be possible without redoing the backbone. Thats a day or two's work and so if somebody wanted an SG bass, its more work than a Firebird but not a massive piece of work. It's adaptation rather than starting new.

 

Edited August 8 by rwillett

[rwillett]

Just now, rwillett said:

Most guitars and bass's are bigger than 220x220mm, though none are 200mm taller (so far). This means that whatever guitar (bass or six string) you want to print has to be done in pieces, no way round that easily (thats a white lie and I'll cover that later).

 

 

The white lie is that you can get around this printing limit by designing and building your own printer,  something like a Voron printer (https://vorondesign.com/). Their system allows custom large print bed sizes. Not cheap though. I did look at this and costed one up and it's around £2-£3K. If I was making printed guitars for a living, I'd probably do it, but for me and friends, not worth it.

 

A 600x450mm printer could do just about any guitar in one print. That then opens up other interesting possibilities, no join lines, really weird designs, cheap custom designs, multi colour designs. I'd love to do a rainbow guitar across the whole body for a friend for Pride. We talked about it, but its non-trivial at the moment.

 

Thanks
 

Rob

[SamIAm]

5 hours ago, rwillett said:

I'd love to do a rainbow guitar across the whole body for a friend for Pride. We talked about it, but its non-trivial at the moment.

That would be totally amazing!

When the band I was in played a pride gig a while back the best I could manage was via various sharpies! 🤣

Sam x

PS Your description of the factors around 3D printing are very eloquent!

[rwillett]

I changed the pickup wire over to check that I was in phase for both the neck and bridge pickups and it made sod-all difference. Still sounded muddy.

 

After looking at it again, I realised that the tone pot which makes a tiny difference when the pickups are in parallel, makes a yuugge difference when the pickups are in series. I'd left the tone pot turned one way as it made so little difference and basically ignored it. Now the bass growls and it's really good. 

 

Will play it a bit more to see what sounds I can get out of it.

 

Changed the wires back.

 

Sometimes the simple solution is the one to check first

[rwillett]

After a few hours in the garage, I now have the aluminium backbone no longer looking like a piece of stock metal I brought off the internet which of course it was.

 

Using a combination of a finger grinder, a Dremel, a half round file and an awful lot of wet & dry from 340 down to 1,000, I took off all the sharp edges and feathered the aluminium in so it matched the curves on the bass body. I am rather pleased as it looks great, it doesn't have the precision of a CNC machine doing this, and I think it benefits from it.

 

I've copper lined all the interior now, tidied up all the bits I wanted to, put it all together and then discovered the straplocks on the body end interfere with tuning, so redesigned the bridge to move the straplocks a little wider apart and printed it off. This is one of the advantages of 3d printing, a piece isn't quite right, redesign and print again. 3 hours to print and done. You can see the holes for the plugs to fit in the bridge adapter as they need to be glued in.

 

 

It's pretty much done now, apart from set up. Its playable but I lowered the bridge by a mm as it was a little too high. I have spent the morning looking for my feeler gauge and the 3/16 Allen key for the truss rod and cannot find them. I did get a Peterson Strobostomp HD for tuning as the ones that clip on a head stock do work on my printed bass, but are a bit slow. Whilst the Peterson isn't cheap, indeed its eye wateringly expensive, its a wonderful tuner and so so fast. I may review it once I've got my head around what it can do.

Edited August 11 by rwillett