Custom Aluminum Neck but NOT a Luthier!

[WilbursaurusRex]

Have you seen this thread: Question about string spacing at nut

No I hadnt but I've checked it out now. Still not positive how I want to go. Its funny, Id almost think you would want equal spacing at the bridge where you have to get your fingers in between and have center to center at the nut since your fretting down on the center of the string

 

[ardgedee]

No I hadnt but I've checked it out now. Still not positive how I want to go. Its funny, Id almost think you would want equal spacing at the bridge where you have to get your fingers in between and have center to center at the nut since your fretting down on the center of the string

iirc that's how Alembic makes them. But the method described in that post makes sense too. Since, basically, either way has a logical foundation, you have to fall back on which one feels better or plays better.

I forgot my own thread on the topic: https://www.talkbass.com/threads/how-can-i-fit-all-these-strings-on-a-fretboard.1632853/

 

[WilbursaurusRex]

iirc that's how Alembic makes them. But the method described in that post makes sense too. Since, basically, either way has a logical foundation, you have to fall back on which one feels better or plays better.

I forgot my own thread on the topic: https://www.talkbass.com/threads/how-can-i-fit-all-these-strings-on-a-fretboard.1632853/

it does look like that's how Alembic does it. I wonder it it is weird to have the strings shift from equal center to equal gap while going down the fretboard

 

[ardgedee]

it does look like that's how Alembic does it. I wonder it it is weird to have the strings shift from equal center to equal gap while going down the fretboard

As long as it's comfortable to play I doubt you'd notice without measuring.

 

[Beej]

On my 5s and 6s, I use what I guess you could call "progressive gaps". I use smaller gaps between the strings at the nut as I go from fatter strings to thinner strings. The centre of the B string is 4mm from the edge while the centre of the G string is 3.5mm from the edge. The gaps vary from 10.5mm to 8.5mm centre to centre. This gapping means that the middle string (A) does not cross the nut on the centreline, but off to the treble side a touch. No one has ever noticed this, even when strings pass over the dots a little offside. Bridge is all equal spacing, centre to centre.

 

[Slidlow]

A friend had one of the 70's aluminum neck basses, had the 'Y' shaped headstock. That thing would NOT stay in tune. It seemed like the heat from your hand was enough to make it expand/contract. Do your homework on this, some pretty tough reasons that evey commercial attempt to do this seems to have fizzled.,

I heard something similar with a Kramer bass. Under stage lights it was claimed to go sharp but was stable at home or in a studio.

 

[WilbursaurusRex]

So due to us being super behind on a group multi part assembly build, and only 4 weeks left….this ain't gonna happen.
Between school and work and interviews I just haven't had the time I thought I might, BUT I definitely intend to build this bass eventually, though it may not have an aluminum neck.
I really appreciate all of the thoughts and feedback and am determined to not let it go to waste!

 

[WilbursaurusRex]

So, after 10 months out of school, I'm revisiting this. I have a Warmoth medium scale jazz bass that needs some work and I've never got along with the neck, so I started modeling a replacement. I had hoped to have a model finished by now but my computer has been down for a couple of weeks.

I'm looking into 2024 vs 6061 aluminum for thermal properties/stability to try and combat some of the stereotype problems of aluminum necks

It will be sandblasted and anodized, however I'm trying to consider additional coating/finishing options to go over the anodize. Not for protection, but for feel. Something that could be buffed up and smoothed out. I'm a bit at a loss, but have looked at a couple different metal waxes, or maybe some thin spray on poly

 

[Bruce Johnson]

So, after 10 months out of school, I'm revisiting this. I have a Warmoth medium scale jazz bass that needs some work and I've never got along with the neck, so I started modeling a replacement. I had hoped to have a model finished by now but my computer has been down for a couple of weeks.

I'm looking into 2024 vs 6061 aluminum for thermal properties/stability to try and combat some of the stereotype problems of aluminum necks

It will be sandblasted and anodized, however I'm trying to consider additional coating/finishing options to go over the anodize. Not for protection, but for feel. Something that could be buffed up and smoothed out. I'm a bit at a loss, but have looked at a couple different metal waxes, or maybe some thin spray on poly

There are many kinds of spray can polyurethanes specifically made for coating aluminum wheels for cars. Tough stuff, can be polished to a gloss. At auto parts stores.

 

[WilbursaurusRex]

There are many kinds of spray can polyurethanes specifically made for coating aluminum wheels for cars. Tough stuff, can be polished to a gloss. At auto parts stores.

Awesome thought. That hadn't even occurred to me. I'll look in that direction. Thanks!

 

[WilbursaurusRex]

So Im still chipping away at this here and there. Definitely a big bite for my first kind of project like this. Im running into some modeling headaches, but its good practice since I dont do much modeling at work. I have my neck laid out with headstock, main neck contour, fretboard and heel. I am trying to loft the heel and headstock to the main profile but am having a bunch of issues where its just not smooth. In addition, lofting from the 1st fret to the nut/headstock tapers the wrong way because I followed the neck contour up the side of the fretboard, so, technically the thickest width of the neck contour is at the fretboard, not the main body of the neck. Here are some pictures of what Im looking at. Im open to thoughts or resources!

 

[Anthony Fury]

What software is this? Speaking broadly here: "loft" or "sweep" operations usually have their idiosyncrasies between platforms, and it's critical to know all the inputs (and the kinks) in order for it to do what you want. There is absolutely no shame in watching a youtube video or joining a forum where a pro guy does a demo on the operation you want to do.

Separate topic and again speaking broadly here: I suggest modeling the part in the same way you will cut it. It's a big step in avoiding "painting yourself" into impossible corners. If you're going to start with a big chunk of aluminum and cut your shape out, then start your model with a big chunk and make "cuts." At each step, you really have to think: "how am I going to cut this?" (On the flipside, if you're 3D printing or forming something, then of course model it as "built up" pieces, as it would be built up or formed IRL.) My $0.02, YMMV, caveat emptor, etc.

 

[WilbursaurusRex]

It's in fusion 360. I'm more familiar with solid works, but fusion is more readily available.

I have an idea of how to hold and mill it but I want to get a full model later out before working in those features

 

[WilbursaurusRex]

Ok so I'm picking up some useful tools for fusion that I'm going to try and apply later this week but one thing that is still a question for me is the neck contour to fretboard transition?

Luthiers, when building, is your neck contour reach the widest point of your neck, or is that contour continues into the sides of the fretboard. If it doesn't continue there would be a fairly obvious transition line, but I guess that is just sanded and blended out when working with more conventional materials like wood?

Here is a chart I found from martins website. As you look at the cutaways, you can see the 2 different methods I'm talking about

 

[Gilmourisgod]

I'm an amateur luthier, but the mistake I made in my first build was having that neck to fingerboard transition too "square", you really want a gentle transition there. I've done the last two builds by extending the neck contour about 1/2 way through the fingerboard edges, and then rolling the hard board edge a little, which feels a lot more comfortable.

 

[Bruce Johnson]

Luthiers, when building, is your neck contour reach the widest point of your neck, or is that contour continues into the sides of the fretboard. If it doesn't continue there would be a fairly obvious transition line, but I guess that is just sanded and blended out when working with more conventional materials like wood?

On most mass-manufactured instruments, the side of the fingerboard and the neck at the glue line are cut square and perpendicular to the gluing surface. With a small rounding at the top edge of the fingerboard. That's the simplest and cheapest way to manufacture it. The main reason is because the necks are routed on pin routers (Old School) or CNC routers with the standard 3 orthogonal axes.

More expensive instruments usually have a more complex shape on the back of the neck, which extends around the edge of the fingerboard. It's a surprisingly complex shape to measure and model. In cross-section, it's not several fixed radiuses; it's a continuously variable radius around the neck. And that variable radius contour also varies down the length of the neck. Even before you get into the blend areas. A well-shaped neck is a full 3-D contour, not just an extrusion of a 2-D contour.

A CNC router with the normal 3 axes can handle most of the 3-D shape on the back of the neck. But to get that shape to wrap around the edge of the fingerboard requires either a 4th axis on the machine (like mounting the neck on a separate Roll axis), or repositioning the neck two more times, rolled at an angle. More fixtures and G-code and alignment. Extra work, which most manufacturers won't do.

 

[Smilodon]

Modeling a neck in Fusion is actually surprisingly difficult. The general shape is easy enough, but Fusion doesn't always handle transitions very well. The temptation is to use the sculpting module, but this could cause issues when you get to machining. I have made a couple necks with Fusion and CNC. Both times i ended up making the shape that needed to be precise on the CNC and made the contours by hand.

One tip I can give you (Unless you already know) Is to make "tools" in Fusion. These are shapes or bodies used to cut or add to your model. For example the transition between the neck and the head stock can be made as a flat profile on the same plane as your fret board and used as a cutting tool using the sweep function around the neck profile. You may need to make several tools like this to get the final result you want. Don't forget to link and project important features between sketches so that things line up properly.

It may also be helpful in some cases to start with your stock as a starting shape and cut away profiles using sweep or boolean operations to create the final model. Or at least make a sketch of you stock. (Construction lines are great for this) This can make it easier to make something that is more practical to machine. This way makes it easier to model in work holding and reference features.

 

[Anthony Fury]

Modeling a neck in Fusion is actually surprisingly difficult. The general shape is easy enough, but Fusion doesn't always handle transitions very well. The temptation is to use the sculpting module, but this could cause issues when you get to machining. I have made a couple necks with Fusion and CNC. Both times i ended up making the shape that needed to be precise on the CNC and made the contours by hand.

One tip I can give you (Unless you already know) Is to make "tools" in Fusion. These are shapes or bodies used to cut or add to your model. For example the transition between the neck and the head stock can be made as a flat profile on the same plane as your fret board and used as a cutting tool using the sweep function around the neck profile. You may need to make several tools like this to get the final result you want. Don't forget to link and project important features between sketches so that things line up properly.

It may also be helpful in some cases to start with your stock as a starting shape and cut away profiles using sweep or boolean operations to create the final model. Or at least make a sketch of you stock. (Construction lines are great for this) This can make it easier to make something that is more practical to machine. This way makes it easier to model in work holding and reference features.

Can Fusion do a lofted extrustion (or cut) using *multiple* guide curves? This is the best luck I've had for the aforementioned pesky heel & headstock transitions.

 

[Bruce Johnson]

Modeling a neck in Fusion is actually surprisingly difficult. The general shape is easy enough, but Fusion doesn't always handle transitions very well. The temptation is to use the sculpting module, but this could cause issues when you get to machining. I have made a couple necks with Fusion and CNC. Both times i ended up making the shape that needed to be precise on the CNC and made the contours by hand.

One tip I can give you (Unless you already know) Is to make "tools" in Fusion. These are shapes or bodies used to cut or add to your model. For example the transition between the neck and the head stock can be made as a flat profile on the same plane as your fret board and used as a cutting tool using the sweep function around the neck profile. You may need to make several tools like this to get the final result you want. Don't forget to link and project important features between sketches so that things line up properly.

It may also be helpful in some cases to start with your stock as a starting shape and cut away profiles using sweep or boolean operations to create the final model. Or at least make a sketch of you stock. (Construction lines are great for this) This can make it easier to make something that is more practical to machine. This way makes it easier to model in work holding and reference features.

I'm pretty sure that's how Rob Allen evolved the model for CNC cutting his necks. He started with the CNC cutting only the easy parts, leaving the transitions rough and oversized. For a while, he was hand shaping the transitions on all his necks. Then he took measurements from the ones that felt right, and used them to create the "cutting tools" to refine the model. He told me that it took him a lot of trial and error and iterations to get the neck, fully shaped by the CNC, to feel the same as his hand-shaped ones. Many necks. Modeling a good hand-shaped neck is more difficult than you think.

 

[WilbursaurusRex]

Modeling a neck in Fusion is actually surprisingly difficult. The general shape is easy enough, but Fusion doesn't always handle transitions very well. The temptation is to use the sculpting module, but this could cause issues when you get to machining. I have made a couple necks with Fusion and CNC. Both times i ended up making the shape that needed to be precise on the CNC and made the contours by hand.

One tip I can give you (Unless you already know) Is to make "tools" in Fusion. These are shapes or bodies used to cut or add to your model. For example the transition between the neck and the head stock can be made as a flat profile on the same plane as your fret board and used as a cutting tool using the sweep function around the neck profile. You may need to make several tools like this to get the final result you want. Don't forget to link and project important features between sketches so that things line up properly.

It may also be helpful in some cases to start with your stock as a starting shape and cut away profiles using sweep or boolean operations to create the final model. Or at least make a sketch of you stock. (Construction lines are great for this) This can make it easier to make something that is more practical to machine. This way makes it easier to model in work holding and reference features.

I'm not familiar with how you are referring to "tools". I understand the tool building in CAM software to designate what kind of tool and geometry you're assigning to a given toolpath, but not the shapes and bodies thing. When I try and look stuff up I keep getting stuff for tool building and tool libraries.