Orf With 'Is 'Ed!

[curtisa]

Good grief. What kind of offset body blank madness is this?

Well, it's got chambers...

[curtisa]

Hmmmm...

Is this cheating?

[curtisa]

Kinda like an Airfix model.

Picture overload

[psikoT]

I love your toys... and that mini CNC has a lot of possibilities.   

[Muzz]

Cool

[Stavromulabeta]

You're on an absolute roll here Curtisa! This is really making it hard for me to put off buying a mini CNC!!!! I'm leaning towards a 3040 but that means doing a fretboard in two passes... not sure if that is to be advised!

I really like the looks of the ergonomics of that *Strandberg shaped lower wing, and that fretboard is going to be ace! I have some funky ideas for fret markers myself - unfortunately my next build is stuck in mothballs until I can get some workshop space! 

[ScottR]

You've been holding out on us, haven't you? I'm pretty sure you didn't just whip that out after work yesterday.

My hat's off to you for your creative design work. Verrrrry nice.

SR

[KnightroExpress]

Wow, simply beautiful. I really need to get a CNC....

[curtisa]

Cheers guys.

 

11 hours ago, psikoT said:

I love your toys... and that mini CNC has a lot of possibilities.   

Indeed it does. Don't be fooled though, there's no way this is a case of 'feed in a design and spit out a finished part in 30 minutes'. There was a MDF jig that had to be made to hold the fretboard blank properly, the fretboard drawing and each component of the inlay had to be tweaked to create the toolpaths for the CNC to follow, the G-code had to be manually edited to get the endmills to cut slots without breaking, I had to get some decent quality cutters for doing the fret slots, there were plenty of experiments on MDF. All in all there's probably a good 2 or 3 days worth of programming and practicing before I was brave enough to pull the trigger on the actual piece of timber. Even after all that the CNC took a few hours in small stages to complete all the work while I watched it like a hawk to make sure nothing unexpected happened. I doubt this could replace the equivalent handmade fretboard in terms of speed.

[curtisa]

7 hours ago, ScottR said:

You've been holding out on us, haven't you? I'm pretty sure you didn't just whip that out after work yesterday.

My hat's off to you for your creative design work. Verrrrry nice.

SR

 

What? Doesn't everyone here work that fast?

In all seriousness, there's probably a month or so of progress compressed into those three posts. I have more to post yet that gets us up to now. I was waiting until I'd finished off the Evil Twin before I started sharing something new. As it is, building has stopped as I'm waiting on hardware to arrive.

[curtisa]

10 hours ago, Stavromulabeta said:

You're on an absolute roll here Curtisa! This is really making it hard for me to put off buying a mini CNC!!!! I'm leaning towards a 3040 but that means doing a fretboard in two passes... not sure if that is to be advised!

Believe it or not that is the smaller version of the CNC you're considering - the 3020. The fretboard had to be milled in two halves. You can see in some shots the fretboard is overhanging the front of the machine while it works on the part it can reach on the table. At the halfway point the fretboard gets moved further up so the completed section overhangs the back of the table and the CNC can then run the second half of the job. Getting the two halves to line up properly is the real trick.

Shameless self promotion - you may want to go to the main site and have a look at the first of a series of articles we're working on. They'll describe this process in more detail.

 

10 hours ago, Stavromulabeta said:

I really like the looks of the ergonomics of that *Strandberg shaped lower wing, and that fretboard is going to be ace!

Yep, I have a soft spot for that Strandberg lower cutaway. Makes a lot of ergonomic and weight-reduction sense without turning the guitar into something that I find visually unappealing (Klein Guitar?). I've noticed recently other people have borrowed this for their builds too.

The rest of the body shape has leanings towards the Jackson Dinky or Ibanez Sabre. I think I've explored the pointy superstrat shape enough now, and if I'm going to experiment with a headless guitar it may as well be an excuse to go for a new body shape with softer contours.

[2.5itim]

4 hours ago, curtisa said:

 Getting the two halves to line up properly is the real trick.

..

After moving your fretboard to cut the second half could you not just pick up your y axis and set your y zero on your last slot that you cut? It should be pretty simple. 

[2.5itim]

Or even set a stop, I haven't messed around with cnc routers much but I run a mill every day and the g&m code should be similar. You could write and run your first part of the program off g54 and at the end of the g54 cycle write a stop to move the router to the end of the table where you want to start your second half and set g55 y zero right there, then move your fretboard to where your last cut slot is pretty close to the cutting tool, move your z axis down slowly to where the cutting tool goes into the last slot you cut, clamp your part down, move your router up to where it's a safe place to start the cycle and then run the rest of your program in g55

[curtisa]

You probably could do it that way. The thing that makes that less attractive is that the fretboard needs to be moved up exactly parallel to the Y axis for each mill cycle. If it gets repositioned with even a tiny bit of angular error the whole thing gets messed up. To do that I need to create a jig with a fence to ensure it stays true to Y the whole time. As the jig I created to do this already has the fence it isn't too much extra effort to install the tiling holes and take all the guesswork out of it by using pins to locate the fretboard for each half of the milling process. Provided I split my CAM files at the same Y co-ordinate every time, the cutter head then only needs to be zeroed on the very first run and the rest just falls into place.

Eyeballing the position of the cutterhead to the last thing that was cut also sounds like a grey area. For fretslots it's probably not too much of a stretch but for something fancier like inlay that gets much harder to pull off accurately. What if the last thing that was cut stopped in the middle of an inlay pocket after hogging out all the waste around it? Surely then there'd be nothing to visually reference against to reposition the workpiece to the tool on the second run?

[Prostheta]

12 hours ago, curtisa said:

Believe it or not that is the smaller version of the CNC you're considering - the 3020. The fretboard had to be milled in two halves. You can see in some shots the fretboard is overhanging the front of the machine while it works on the part it can reach on the table. At the halfway point the fretboard gets moved further up so the completed section overhangs the back of the table and the CNC can then run the second half of the job. Getting the two halves to line up properly is the real trick.

Shameless self promotion - you may want to go to the main site and have a look at the first of a series of articles we're working on. They'll describe this process in more detail.

 

Yep, I have a soft spot for that Strandberg lower cutaway. Makes a lot of ergonomic and weight-reduction sense without turning the guitar into something that I find visually unappealing (Klein Guitar?). I've noticed recently other people have borrowed this for their builds too.

The rest of the body shape has leanings towards the Jackson Dinky or Ibanez Sabre. I think I've explored the pointy superstrat shape enough now, and if I'm going to experiment with a headless guitar it may as well be an excuse to go for a new body shape with softer contours.

 

Yep. It's a gem of an article and I'm sure it'll spark up plenty of ideas in other people who can wrap their heads around the key concept.

http://www.projectguitar.com/articles/workshop_and_tools/milling-fret-slots-on-an-undersized-cnc-machine-part-1-r30/

 

[curtisa]

I suppose I should provide some kind of overview of what's going on in the way of materials and specs.

Once again these will be two concurrent builds. Once again I'm trying something new, so these will be headless multiscale 7s, and as the bridge pieces require some form of clearance/access around them to twiddle the tuners, it's time to experiment with a new body shape too.

#1 will be getting:

• Chambered Blackheart Sassafras body with myrtle top
• 5-piece laminated neck in Cheesewood and Blackwood
• Cheesewood fretboard with gidgee inlays
• 25" / 26" scale length with 9th fret perpendicular
• String locks and bridges by Technology 4 Musicians in black
• Fishman Fluence Modern active humbuckers
• Single volume + three position switch. Push/pull on the volume pot to select between the two voicing modes that the Fluence pickups feature

#2 will be identical to #1, but differs such that:

• Chambered Blackwood body with non-fancy top.
• Swirl paint finish (oy vey!). Don't worry, nothing quite as loud as the 90s Ibanez Universe that everyone knows so well.
• Mulga fretboard with Cheesewood inlays
• Lace Alumitone X-bar pickups
• String locks and bridges/tuners by ABM in black
• Single volume + 5 position blade switch. Pickup selection options yet to be determined, but most likely some kind of auto-splitting stuff in between the usual 2x humbuckerpositions

Cheesewood (pittosporum bicolour) is a native Tasmanian timber. Very hard, very dense, very pale, reasonably difficult to come by in large pieces. I picked up a fairly large piece of it some time back for an OK price, enough for two necks.

Blackheart Sassafras is also a native Tasmanian species. Quite light in weight. It's usually known for its pronounced black and brown streaks that develop from fungal attack (hence the name), probably not unlike spalted Maple. The piece I'm using is fairly mildly streaked, with only a little bit showing at the extreme edges of the body.

Mulga is an arid-area timber from mainland Australia, also very hard.

So:

Blackheart Sass offcuts being used as clamping spacers at the back:

[curtisa]

Trussrod access on the headless neck becomes a slightly more challenging prospect given that there's no angled headstock to provide an opening for a routed channel. Kinda has to be built more like a Fender neck with a drilled-through access at the end:

Then the channel itself needs to be routed, although stopped short such that it doesn't go the full length of the neck:

And hopefully it all lines up properly for it to slot together:

[curtisa]

Carbon fibre rods too. I suspect this is largely overkill. The laminated Cheesewood neck is super rigid by itself, but I'd like to go for a slimmer profile, so any weight relief with the added strength of CF will make me feel better at least:

Epoxy to keep it all in place. The greaseproof paper is there to stop the epoxy from sticking to the clamps and caul:

One thing I will say about a headless neck - having no headstock makes construction a whole lot simpler. No scarf joint to worry about. No headstock to get in the way of clamping or routing operations. The whole neck is essentially just a plank.

Fretboard gets pinned in place to assist with aligning it while the glue dries. I added a bit of tape to mask off the headstock-end of the fretboard to aid cleaning the squeeze-out at this end, as it will be on display underneath the string clamps:

Must not forget a bit of silicone in the trussrod channel:

After the glue dries the excess can get trimmed on the router table. Headstock left purposely oversized until I can verify the size and shape of the string clamps (still waiting on Mr Mailman):

[KnightroExpress]

Looking lovely, as usual! I always feel the need to buy more clamps when I see pics like the second-to-last one there. 

What hardware are you going to use? I'm planning a multiscale headless build and can't decide what hardware to go with.

[Prostheta]

Those clamps develop 150lbs of force, which I think is over the size of the pad....about a square inch....that's 12x 150lbs (1800lbs) over a surface that's what, 20" x 2,25" (45²in) or thereabouts? 40PSI is a little low. Have a read of this for reference;

http://www.finewoodworking.com/item/27122/how-to-glue-up-joints-the-right-number-of-clamps
http://www.finewoodworking.com/item/27121/how-to-glue-up-joints-different-woods-need-different-clamping-pressure

A fingerboard isn't the same as a structural component of a large-format piece of furniture, but I'd feel more comfortable doubling that pressure. Not that you've ever had trouble with your boards of course, and I know we've had this conversation previously. I just like running the numbers, but that's never a surprise is it?

[curtisa]

4 hours ago, KnightroExpress said:

Looking lovely, as usual! I always feel the need to buy more clamps when I see pics like the second-to-last one there. 

What hardware are you going to use? I'm planning a multiscale headless build and can't decide what hardware to go with.

Ta.

Hardware for the first instrument is by Technology For Musicians in Italy. Very much a small scale operation. He makes them as he receives the order, but from all I've read and heard they're about the best value for money headless units you can get your hands on.

Number 2 is getting ABM hardware. I've always liked their individual (non-headless) bridges, so I'm keen to see how their headless equivalents stack up. The nut assembly is different to the T4M units, so the headstock will need to be designed differently to accommodate it.

[curtisa]

3 hours ago, Prostheta said:

A fingerboard isn't the same as a structural component of a large-format piece of furniture, but I'd feel more comfortable doubling that pressure. Not that you've ever had trouble with your boards of course, and I know we've had this conversation previously. I just like running the numbers, but that's never a surprise is it?

Yeah, I've never had an issue with clamping by sheer volume of clamps rather than upping the pressure, but I will have a look at those articles.

[KnightroExpress]

As luck would have it, those are the exact 2 systems I'm pondering. I'm looking forward to reading your impressions of each!

[curtisa]

May be a little while yet before I get my hands on them, but it will be good to see them both side by side.

We're not exactly flush for choices when it comes to headless hardware. With Ola Strandberg halting sales of his headless bridge assemblies late last year, an already sparsely populated area of guitar building is a whole lot smaller.

[KnightroExpress]

Indeed, the field is limited at best. The only other headless manufacturer I know of making multiscale capable bits is Mera out of Ukraine. I've heard good things about his hardware so far.