Project: Earthstone

[Prostheta]

34 minutes ago, komodo said:

I could probably live with a guitar that had strings too close together, high action, weak pickups and a loose jack . . .as long as it had a grain matched cover. Did you just drop a Magic the Gathering reference in there? - pixie manipulation chamber

AvE reference for us pixie wranglers, however we'd likely still be wood elves by his standards.

[Bizman62]

30 minutes ago, Prostheta said:

I couldn't help but give it a quick spray of DNA to identify any other areas needing work.

For a moment I thought you had spread your own DNA, wondering how you could cover the entire area with such a small drop. I won't tell what popped into my mind after saliva! The next sentence revealed the truth.

They didn't teach abbreviations like that when I was at school!

[mistermikev]

talk about documenting your build... lots of good stuff there.  thanks for that.

[Andyjr1515]

Excellent run-through, Carl, and already looking good.

Yes - I did notice the 'bleed' in the sapele.   Never seen that before with that particular wood type.  Any idea what is going on there?

[Prostheta]

I'd mentioned briefly that Sapele likes to stick to everything. It might be that this is related to some constituent that is solvent with alcohol. But like yourself, I've never seen it to this degree before in woods outside Andaman Padauk and similar. I might drag out a piece of scrap and see how much I can strip it with DNA, and whether that affects the end result. 

[Prostheta]

On 12/15/2019 at 9:25 PM, komodo said:

I did that same pickup merry go round with that Dragon guitar. The SD SH-5 (Cer), SH-11 (A2), SH-14 (A5) are all in that ballpark. Not really low output though at 14k? In the end I used a C8 which is a custom SH-5 using an Alnico 8. Interesting, high output, bell-like. It would pair well with a thick mahog body.

I'd been thinking about this post for a while as grist for the mill. The bottom line for me on this was low wind, touch sensitive and squishy. Something that benefits from feel rather than flattery to the point of hiding things. I'd considered a pair of APH-2s, or even a Black Winter set based on feedback from users expressing their musicality. It would have been easy to kick this back into vintage LP pickup and circuit territory which has been done to death. Instead, picking what I know and translating it across with a little more of what I want seems less of a step into the unknown. Conservative to a degree, but baking in what I like. 

Sapele is the wild card here. I've found it a bit snappy and bright before, so I could easily find that the 500k circuit is brittle sounding. Brass should round this out, and maybe going for 250-300k might tame it. That can be played around with.

Not sure about high output or bell-like. Maybe on a guitar with higher tension, longer scale or whatever. I like riding on the neck with the tone rolled back, playing for notes that bloom. This takes fishing for tone a bit. PG necks sound like they take what I like in the '59 and even out the low end, maybe detail the top a little. I'll report on the comparison. 

[Prostheta]

Doing a bit of research, it appears that the wider string spacing of a Nashville style bridge is more amenable to the wider pole spacing of a trembucker or f-spaced pickup. That complicates a couple of things, but at least gives me a solid basis to work from. The largest hurdle is a covered TB-11 humbucker, as they're commonly sold uncovered. I might have assistance pinging one over from the states though, so fingers crossed.

[Prostheta]

So let's discuss the neck options. Firstly, I've been sat on a 5-piece laminated Sapele blank for a while now. The laminates were pinstriped with 0,7mm Maple veneer for contrast. Overall the blank's dimensions are large enough to do an entire neck-through instrument, however I think that equally it can be cut down to two set or bolt-on neck blanks. Once I get a little bit of time to sit down and draw out a cutdown plan, I can figure out how best to make use of it.

Primarily, there's the choice between whether to do this neck as a single piece headstock or scarf it. For what it's worth, the blank should easily support single piece and scarfing a neck to match up pinstripes is a pain at best. Normally this would be a good argument for backstrapping a headstock in order to disguise the scarf (and hence any pinstripe join issues) by placing the join within the volute, or alternatively an "over under" scarf where the join lays within the headstock itself.

This shows the two most common types of headstock scarfing strategies. The arguments for and against each imply that the top produces a hump in the first position from wood movement, and the second requires a wider neck component or ears to be glued onto the headstock. Between the two I prefer the second when used in conjunction with a headplate and backstrap with ears as the entire scarf joint can be hidden unless one carefully reads the grain direction.

 

Having gone back and forth a few times over this, I decided to stay with a single piece neck rather than scarfing. The advantages of headstock strength from eliminating most short grain are well-known, however there's a lot to be said for the relative simplicity of an entire Mahogany back continuing up through the neck with the only visual addition being the pinstripes. An over-adornment of contrasting woods seems a little more excessive than what I'm hoping for. Enough and not too much.

This is the blank as it stands. Dimensions in the cross section are 112mm x 65mm which more than adequately caters for both an 85mm headstock and an 11° headstock angle.

 

Okay, so now I'm settled on material and basic constructional approach, I can look at adding in some control to the neck. I've a few options for truss rod.

The first would be a big single-acting rod set in an aluminium U-channel, which is a style I love for bass and sometimes guitar. Another is a lighter single-acting dual rod which I'm not too much in love with. They can rattle when not under tension, and they don't really "become part of the neck" sitting in a channel. They're simple to install and lightweight however, which makes them popular however in general they're pretty cheap and cheesy imports outside of the rods sold by LMII and Allied. Great for thin necks that can't support big rods in deep channels. Both of these have a similar problem in how to plan the access for the nut. Shallow headstock angles and rods locating close to the fingerboard "reveal" high and flat at the headstock, leaving fragile wood under the nut. It's a personal bugbear.

The last choice is a traditional compression-style truss rod. These are by far the most fiddly to install and the most sensitive/least-stable of them all; being an integral part of the neck, when the wood moves dimensionally, the rod's acting force alters also. They need the most maintenance of all truss rods, and also the most work planning and installing. That said, being an integral part of the neck they are regarded as creating more "musical" and "lively" necks. How true that is in reality is difficult to quantify given the number of terrible sounding neck with compression rods and the number of awesome necks with cheap dual rods, etc. The crossover between can be pretty large, and necks are a lot of factors rolled into one. How the rods affects it all is subject to immense faith and general levels of omphaloskepsis unseen outside the "hide glue or astroglide?" debate.

Still, a compression rod is simple. Executed properly, it only requires blue moon maintenance at the adjustment nut end to prevent seizure. Whether the feel of going vintage on this has bearing on the realised instrument is purely in my head, and that's fine. If it makes me feel one way whilst playing the instrument, that's the true value of mental investment right there. The access of curved rods tends to lend itself nicely to angled headstocks in my mind. Plus, I can fabricate everything from the rod to the half-moon washers and even the brass nut itself. That has value in and of itself. I like that.

Cosmetics-wise, I've settled on finishing the headstock with a matching headplate of the flamey Mahogany used on the body. I may inlay the headstock and maybe even the fingerboard with silver (here's looking at you, @komodo!) in some manner rather than using a logo. Something simple and distinctive without being specific.

In other news, I may spend some time experimenting with tinting Tru-Oil and seeing whether it is possible to encourage a light burst effect through many thin coats. Given how short an open time Tru-Oil has, getting a good balance of pigment between sessions might be a trick.

[komodo]

Love those pinstripes! That's a real nice piece of Sapele.

Takeaways:
-omphaloskepsis
-"hide glue or astroglide?"
-silver inlay

Which reminds me, I should be off the computer and working!

[Prostheta]

....on a Sunday?

I've independently explored silver inlay in combination with Ebony for furniture work. The fine flat inlay line work using <1mm flat silver ribbon is something I think would be super cool for the fingerboard. A couple of winding lines or similar.

The sort of inlay work I'm wanting to practice and maybe incorporate is this kind of thing....

 

This is an idea closer to what I might incorporate in the fingerboard. I'll be adapting this for a couple of bedside tables I'm finishing up, and that just screams "pantograph" to me. Absolutely perfect opportunity.

 

Generally these types of inlay are sat somewhat proud of the surface, whereas fine silver wire inlay is finished flush. The latter being more appropriate for a fingerboard (if I go that route) and the former ideal for headstock adornment.

[ScottR]

On 1/5/2020 at 5:56 AM, Prostheta said:

n other news, I may spend some time experimenting with tinting Tru-Oil and seeing whether it is possible to encourage a light burst effect through many thin coats. Given how short an open time Tru-Oil has, getting a good balance of pigment between sessions might be a trick.

This would be the time to spray the Tru-oil.

SR

[ScottR]

23 hours ago, Prostheta said:

....on a Sunday?

I've independently explored silver inlay in combination with Ebony for furniture work. The fine flat inlay line work using <1mm flat silver ribbon is something I think would be super cool for the fingerboard. A couple of winding lines or similar.

The sort of inlay work I'm wanting to practice and maybe incorporate is this kind of thing....

 

This is an idea closer to what I might incorporate in the fingerboard. I'll be adapting this for a couple of bedside tables I'm finishing up, and that just screams "pantograph" to me. Absolutely perfect opportunity.

 

Generally these types of inlay are sat somewhat proud of the surface, whereas fine silver wire inlay is finished flush. The latter being more appropriate for a fingerboard (if I go that route) and the former ideal for headstock adornment.

Nice.

These belong in the new non-guitar build section.

SR

[Prostheta]

Oh, these aren't my work but I wish they were! I'll certainly be detailing my work over there. I might add in that Ebony and silver inlay motif to the head plate, however I'm tempted to cut into this small burl I found on a fallen branch here in the forest. Making that into a raised carved inlay should be nice. I'll climb into the loft and see how dry it is....

[komodo]

This is exactly what I'll be doing today. On the Black Queen, the stars are silver wire, but for the star with light flares I've hammered the thickest silver wire into ribbon. Today I will route (or cut) a thin channel and inlay the ribbon to make the flares. Whereas pearl gets extremely delicate as you cut fine detail, the wire can be hammered as paperthin as you want and it's still metal. Also, it will be contrasted by the pearl planets next to it. Of course this is all great on paper...check my thread later to either see it done, or a pile of tears.

[Prostheta]

Haha! Definitely!! I've been experimenting with inlaying silver wire, manipulating the shape and figuring out a workflow. For example, making up a 3:1 paper template for the pantograph and having that cut a 1,5mm wide channel for a meandering wire shape is easy, however making the wire conform to that desired shape isn't. I might drop down to my 1,35mm wire for these since it's easier to bend and shape and cut 1,0mm channels instead. The runout on my Dremel's spindle means the final channel width is slightly over 1,0mm anyway, so it's much of a muchness. I've also experimented with working the other way around, that is, bending the wire as near to the desired shape as possible, then pressing that into the wood and following the impression with the pantograph manually. This works reasonably well with the 1,5mm wire but I haven't tried it with the narrower gauge yet. I think the 1,5mm and 1,35mm should make a nice variety of dots around wire designs and the 1,35mm may make life easier.

As far as this relates to the guitar project, I'll likely do some form of wood and wire inlay carved bolection design in the headstock. That is, raised above the surface of the headplace a mm or two. I forgot to grab that burl down from the loft....

[Prostheta]

Right, I've been a bit sidetracked from this whilst I waited for the brass plate to be delivered. As usual, that got messed up so I'm having to get myself into the frame of mind to push the project forward in other areas. The neck is the big one, however I need to do a bit of design work in order to produce the truss rod slotting jig.

Let's document this as I work.

I'm planning on making a spindle moulder jig that that will accept the neck on it's side, running a copy ring against the base of the sled. This jig will exist solely for this project only, and then be broken apart, clamps repurposed, etc. The neck still exists as part of the larger blank described earlier, and I think it might be wise to get around to figuring out how best to cut it down.

Primarily, the neck will extend through to the rear of the neck pickup rout. There's not a lot of meat left in the neck tenon after routing out the pickup cavity, however once the pickups are in my hand I'll only take as much material as is truly required. I've idly been considering trying a set of Fishman Fluence classic pickups as opposed to the SD set proposed previously, which may require a slightly deeper rout for the connectors. Again, an issue for when the pickups are in my hand.

So broadly speaking, this is how the neck will play out. A blank >647mm x 40mm x 85mm with the majority of the length at 20mm. Quite likely the best plan of action taking this from the large blank would be to cut the headstock face angle, crosscut the blank at the body end, bandsaw the rest, clean up the heel against the table saw fence set at 22-23mm and see what the blank wants to do after a few days. Sapele is a particularly fractious wood thanks to the trees not growing as large as say, Khaya, and certainly it's rarely straight grained. If it in fact it does want to play around, I can face off the fingerboard gluing plane and machine the heel face later. To me that seems like a good working target for tomorrow's work if I nip into my workplace.

 

So, onto the things that I can plan between now and seeing whether the neck wood has some hidden surprises built in.

The truss rod will have an anchor placed in the middle of the 18th fretting location. The style of anchor will be a simple barrel nut; a short length of 10-12mm steel cross drilled at 5mm, tapped to M6 for threading onto the truss rod which is then itself peened over at the back to lock it into place.

Sauna's ready. Will continue later. Quite likely, after I have cut the neck blank.

[Prostheta]

Bit of a megapost here, so hopefully the post rendering bug I get on Android/Chrome doesn't hit anybody else....

As explained, I wanted to do a limited number of operations on the neck to remove it from the larger blank to leave it for a week or so. That gives me time to design and build the truss rod slotting jig....

First job is to cut the headstock face. This won't be a finish cut, but near as damnit. Since the blank is still very large, square and has wide reference surfaces to align off I wanted to do these operations first. It makes the whole thing cleaner, safer and more reliable. I know that few people will have ready access to this type of machinery, however I hope the thought process translates across and is still useful. Posting blatant machining porn is fun but doesn't always provide good learning material. Questions are welcomed of course!

Bandsaw with 35mm blade. I drew out the headstock angle on the blank by measuring the opposite and adjacent sides of the triangle they form on the side profile. This is a far more accurate approach than using a protractor or other device, even though in principle the angle accuracy isn't too important. The main point is that the neck to headstock angle break point is at the right place and the length of the headstock face is sufficient for the intended design.

 

The cut was made to within 2-3mm of the drawn line as I want to clean up the face using a table saw....

 

Cutting a shallow angle with high cut size on a table saw with respect to the blade can be tricky (and unsafe) without a stable and well-retained workpiece. I decided the best way to do this would be to grab a thick piece of plywood (this was something like 2x 21mm sheets laminated from the spares rack) and cut in the desired angle off from 90° and use that to aid alignment. First, I squared up the piece.

 

Set the table compound at (90°-11°)= 79°

 

Cut one edge of the alignment piece....

 

Giving us an edge which is now able to provide a good 11° reference with respect to the compound cross cut fence.

 

Reset the compound to 90°, place the blank in position and use a crosscut fence stop against the plywood to prevent sideways movement.

 

A modified F-clamp fitted into the sliding compound table's t-track holds the workpiece in place. Everything must be secure and unable to move. Removing the majority of the waste prior to this operation allows the cut to be "open" rather than a captured cut. Combination blades such as these can't handle a lot of waste (large tooth count, small gullet capacity) so allowing waste to exit out one side of the blade eliminates burning at the expense of slightly lop-sided tool pressure. This can in theory deflect the blade slightly to the right or push the workpiece out to the left, however a sharp saw blade and the stop (out of frame to the left) allay this.

 

As it stands, the blank starts out at 113mm wide whilst the blade size can cut a hair under 100mm. This isn't a problem as we can reduce down the cut size later.

 

Flipping the blank over to inspect the initial drawn cut line....close as anything.

 

Next, I cross cut the blank at 28mm depth of cut to establish the end of the blank. It's a mm or two longer than should meet the back of the neck pickup rout, but as discussed this isn't a critical measurement. If anything, cutting a neck slightly shorter than the rout and wedging it into the rout by pushing it forward from the back of the neck pickup with a clamp configured as a spreader....wait, forget that. We'll cross that bridge when we come to it

 

I struck a line at 25mm from the neck face and 20mm from the headstock for bandsawing.

 

As is customary, foot must be in shot.

 

In spite of the blade being super wide, the curve can be managed from headstock to neck.

 

I'm now able to take the detached neck blank down to a little over the required 85mm that the headstock design requires. I calculated 113mm-85mm, or 28mm of removal. Half that each side minus a mm each gives us:

 

Then....

 

Even though both cuts need to be done safely, this one has to have attention borne in mind as not to pitch the workpiece up applying pressure at the back end. This would be bad. Also, I'd never attempt this sort of job without using a riving knife, or splitter most call them. Any sideways movement in the workpiece from the fence causes ultra dangerous catastrophic kickback. Never never never. It's just not an option!

 

So that's our 87mm wide blank. You can see that the table saw cut wasn't absolutely flat. There's always flex in some part of a setup even when you think it's more than adequate. This isn't something that a sanding block or hand plane can't fine tune. Literally less than half a mm of fix, but important to keep sharp and coplanar.

 

I shaved a little under a mm from one side to centralise the laminates. It's hardly useful I think, but at least allows me to calculate equal measurements from edge to edge if I need to do so....

 

[Prostheta]

For reference, a useful calculation to know is your basic trigonometry for shallow angles. Generally this ends up being the TOA part of SOHCAHTOA ("Some Old Hippy Caught Another Hippy Tripping On Acid"), or T=O/A.

That would work out as:

tan(θ) = O/A 

tan(θ) = 28,9mm/148,7mm

To do this on your calculator, type 28,9 divided by 148,7 then press either Inv/Tan, ATan or Tan⁻¹ whilst in degrees mode. This should result in 10,99°.

 

If you want to do the reverse to calculate out what the adjacent (the part 148,7mm is in this case) and opposite (28,9mm) are from the hypotenuse (length of the headstock) and neck angle, use either one of the others and Pythagoras.

That is (assume a headstock length of 151,5mm):

sin(θ) = O/H rearranged to sin(θ) * H = O

sin(11°) * 151,5mm = O

Typing that in would be 11, Sin * 151,5 giving you 28,9mm.

This gives you two values of the sides. Since we've identified these as opposite, adjacent and hypotenuse with respect to one angle (11°) we'll use that labelling. Pythagoras....

A² + O² = H² rearranged to A² = H² - O²

A² = (151,5)² - (28,9)² = 22952,25 - 835.21

A² = 22117,04

A = √22117,04 = 148,72mm

 

You could do the same thing using CAH to work out the adjacent, then Pythagoras to work out the opposite as O² = H² - A²

Roll your eyes as much as you want about the mathematics, however things like this never went in at school since for most there wasn't a practical real world use at that stage. For me, applying makes it an invaluable tool rather than being more like an intellectual exercise. Moreover, when applied meaningfully it can help you increase your precision. Drawing out a shallow angle against a flat surface is prone to all kinds of errors. If you know how far that angled line is from the flat surface over a specific distance, you're immediately working in less than tenths of a degree. More than enough to accurately set a neck angle to a body and ensure strings hit the bridge at the height you want them to.

Enough Sunday blathering megapost. Happy to answer any questions or detail certain areas better if I glossed over anything.

[Bizman62]

6 minutes ago, Prostheta said:

Roll your eyes as much as you want about the mathematics, however things like this never went in at school since for most there wasn't a practical real world use at that stage.

So very true! I learned to calculate ballpark level percentages in my head in my previous job as a representative. The customers double checked that with their calculators and were amazed about how accurate my estimates were.

Had I been interested in guitar building during my school years the limit calculations would have made more sense. If I've understood it correctly, they're used for fretting.

[Prostheta]

Going slightly OT, the whole "common core" thing where kids are taught to estimate and marked down for calculating instead is misguided. Estimation is a real skill same as calculation, especially when you don't have numbers or exact quantities. Fermi estimation is a great one, but not so useful for making instruments. Fretting "estimates in centimetres...metres would be silly" hardly helps! So yeah. Calculating is the gold standard, estimating is good to illustration but not for reliance.

[Prostheta]

Whilst it's on my mind, you can gauge the sort of variance in headstock angle (or whatever) by playing around with a mm either side of you value. After all, we can mark to the nearest mm (or Imperial equivalent, what, a 32nd?) pretty reliably.

Let's decrease the adjacent by 1mm and increase the opposite by 1mm to force a larger angle than required.

tan(θ) = O/A

tan(θ) = 29,9mm/147,7mm = 11,44°

The opposite way is increasing the adjacent by 1mm and decreasing the opposite.

tan(θ) = O/A

tan(θ) = 27,9mm/149,7mm = 10,55°

So we're talking a variance of a degree if you're marking a little sloppily. For a headstock angle, that's very little. For a neck-body angle using this method, a mm of play in the opposite either way represents a fraction of a mm variance at the bridge. Certainly better than using a protractor!

[Prostheta]

Okay, let's talk truss rod routing sleds.

Digging into the spindle moulder cutters, I decided on using a ⌀125 bearing and a 6mm cutter that is currently ⌀145,5mm (sharpened down from ⌀150mm). Using an offset like this allows me to have the cutter extending into the workpiece without removing too much of the sled material. We need to know a few things first of all. The location of the anchor, the truss rod access location and the neck dimensions. As mentioned, the anchor will sit between the frets either side of the 18th fretting location and the rod access will be a recessed "Gibson style". I haven't done any drawing yet, so I'm sort of typing this as I develop the idea.

I'll draw out the neck side profile so we know where the anchor lives, the neck thickness taper and the truss rod nut location. Let's draw in 19mm thickness at 1st and 22mm at 11th. I'd like to try and make a ⌀15mm counterbore/spot facer work for nut access with a long wrench rather than the full on ⌀3/4" Gibson use. Besides, I have a ⌀15mm. The rod will be a metric 6mm, larger than normal.

 

So, I drew out the neck taper according to these values, then created an offset line 6mm in. This represents the minimum thickness from the "outside" to the truss rod plus half of the rod's diameter. I then drew a 15mm x 50mm box representing the counterbore and placed that at the headstock where I want the rod nut access to "reveal". A similar box representing the barrel anchor is drawn at 18th. A three-point circle can then be drawn to show a constant arc between the middle of the barrel nut, the centre of the rod at minimum point (dead centre) and where the rod meets the access.

There's a number of reasons I'm not happy with this. Primarily, the shallower headstock angle of 11° instead of around 15° means a longer truss rod access channel, or a shallower one for the equivalent length. Bringing this out to a better depth removes way too much material for my liking. A common issue with compression rods. I sort of had an idea that I would run into this issue when deciding on headstock angle, but left it as a bonus ball problem to solve. Good times. The upshot of this is that there is little room for an acorn nut to sit below the surface of the headstock. Partially this will be less of a problem with the headplate, but still a problem nonetheless. Another option would be using a round rod nut with a cross cut. This would allow the counterbore to have less diameter, but would both require a slightly different rod path for more or less the same cut depth. The barrel end would possible need alteration also on the basis that the central point of rod action should be more or less equal to the point that the string tension acts most. This is possible but a lot of thinking and time required to do that. Meh.

The easiest solve would be to use a straight rod, for which my preference would be an aluminium U-channel type. I'll ruminate on this during my evening shift, methinks.

[Prostheta]

The takeaway from this is to thoroughly plan out your neck prior to cutting anything.... 

I can either use a workaround as described, make a new neck blank or simply change rod type. Hmmmm

[pshupe]

Great build thread.  That Rhino model looks awesome.  I gave Rhino a try but never really got the hang of it.  I use Fusion 360 now and it is great and it is free.

I was wondering why you are not using a double action truss rod in a flat slot?  Actually Gibson used one way rods in a straight slot as well.  The slot was deeper at the heel end which allowed it to work.  I've built a few that way but it is a good idea to build forward bow in the neck when clamping on the fret board.

Cheers Peter.

 

 

 

[Prostheta]

Thanks Peter. Yes, I'd considered a flatter rod. I know some boutique luthiers use that method, however I've always been of the opinion that a little pre-loading helps. The larger issue is the lack of headstock angle reducing the real estate for the cavity access. I'm leaning towards using the other half of the neck blank for a second higher angle neck, or simply using one of my aluminium rods.