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First bass build, hoping for sage wisdom


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Hello lovely fellow builders! Been lurking here reading for a while, and finally created an account for a couple questions I dont believe I've seen an answer to. If there are threads answering these questions I'm open to being directed to those and having this thread closed.

As the thread title implies, I am in the planning and acquisition stages for a from-scratch 5-string bass guitar. I plan on having a through-neck, 24 fret design in a relatively rare 30" short scale length.

My questions both have to do with the neck and fretboard. The first is, is there any standard measurement for the length of the fretboard and neck itself relative to the desired scale length? I assume it depends on the number of frets already, but my thought was more specifically for the distance from the end of the fretboard to the bridge, as I assume there is some unspoken "standard" to make room for any and all pickups.

My second question has more to do with the neck. I understand there would have to be a point where the neck would just snap from the string tension without some kind of reinforcement,  but past that how much does the depth and curvature of the neck matter when building? I want a neck that is as thin and flat as possible without serious risk of snapping in half from regular use.

Thank you in advance for any and all advice you can offer!

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7 minutes ago, TheRavenOfDiscord said:

The first is, is there any standard measurement for the length of the fretboard and neck itself relative to the desired scale length? I assume it depends on the number of frets already, but my thought was more specifically for the distance from the end of the fretboard to the bridge, as I assume there is some unspoken "standard" to make room for any and all pickups.

There is no standard to speak of. You're left with whatever room is available after you subtract the remainder of distance from the last fret on the fretboard, minus any excess fret board extension past the last fret.

Say you have a 24 fret neck on a 30" scale length. The remaining scale length between 24th fret and bridge will be approximately (30/2) - (30/4) = 7.5". There will be an extension of the fret board of say 0.4" so that the last fret has some meat in the fret board to attach to, so your total remaining length between the neck and bridge will be around about 7.5 - 0.4 = 7.1" for you to position pickups at your leisure.

 

14 minutes ago, TheRavenOfDiscord said:

My second question has more to do with the neck. I understand there would have to be a point where the neck would just snap from the string tension without some kind of reinforcement,  but past that how much does the depth and curvature of the neck matter when building? I want a neck that is as thin and flat as possible without serious risk of snapping in half from regular use

All modern necks will at the very least have an adjustable truss rod installed to help counterract the pull of the strings. Necks prone to twisting or warping (eg, long scale lengths, high string tension, made from materials not known for their lateral strength, super-thin profiles etc) will sometimes also have carbon fibre rods or beams installed to help stiffen the neck further and provide more rigidity. Dual truss rods are sometimes used to not only allow for backbow/forward bow adjustment, but also twist correction.

The risk with going super-thin isn't largely from snapping the neck, but rather having a neck that flexes easily. This can play havoc if you're a player who has a habit of being physically active while playing (getting 'in the groove' you can easily flex the neck and throw the instrument in and out of tune and/or cause action issues as the neck bends), or during temperature or humidity changes, where the materials in the neck do not have enough inherent strength to withstand moisture or temperature changes and thus allow the neck to change shape. Best case you will find yourself doing numerous trussrod adjustments as the neck flexes in response to the environment. Worst case you'll end up with a neck that ends up warped and unplayable at certain times of the year...or just warped and unplayable.

If this was a first time build I'd check out some spec sheets for some commerically made basses of similar specifications and see what dimensions they offer on their necks, and whether carbon fibre reinforcement was used and/or dual truss rods. I'd then base the build on similar specs and not deviate too far beyond them. Even longscale 7- or 8-string guitars might offer a clue as to what is practical in the way of neck thickness and reinforcement methods.

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11 minutes ago, curtisa said:

There is no standard to speak of. You're left with whatever room is available after you subtract the remainder of distance from the last fret on the fretboard, minus any excess fret board extension past the last fret.Say you have a 24 fret neck on a 30" scale length. The remaining scale length between 24th fret and bridge will be approximately (30/2) - (30/4) = 7.5". There will be an extension of the fret board of say 0.4" so that the last fret has some meat in the fret board to attach to, so your total remaining length between the neck and bridge will be around about 7.5 - 0.4 = 7.1" for you to position pickups at your leisure.

Ah, wonderful! Some math for a left brainer! Joking aside, that makes a lot of sense. That basically means I need a final length of 22.9" thereabouts in the fretboard.

1 hour ago, curtisa said:

All modern necks will at the very least have an adjustable truss rod installed to help counterract the pull of the strings. Necks prone to twisting or warping (eg, long scale lengths, high string tension, made from materials not known for their lateral strength, super-thin profiles etc) will sometimes also have carbon fibre rods or beams installed to help stiffen the neck further and provide more rigidity. Dual truss rods are sometimes used to not only allow for backbow/forward bow adjustment, but also twist correction.

I didnt even consider the neck twisting. I'll have to look into either a dual truss system or adding carbon fiber rods, or both if I want a bit of overkill.

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2 hours ago, TheRavenOfDiscord said:

The first is, is there any standard measurement for the length of the fretboard and neck itself relative to the desired scale length?

The only "standard" of any guitar is that the 12th fret is right in the middle of the scale which in turns means the distance from the nut to the bridge. Thus in your case the 12th fret will be at 15", leaving another 15" to be shared between the dusty frets and the pickups. You can make the neck very long or push the fretboard and neck inside the body as long as the scale stays intact. If you need more clearance for the pickups you'd have to reduce the amount of the narrow frets.

image.png.0c8dca975de7a00850fe894e3a090d0e.png

The above illustration also somewhat addresses the strength issue. A shorter neck is less affected by the string tension, of course with the cost of reducing the access to the higher frets. The maximum amount of frets needed depends highly on your playing style. Anyhow, as @curtisa said, there's ways to increase the strength and stiffness of a long and thin neck. A dual action truss rod assisted by carbon fibre strips on a quarter sawn tight grained neck of good quality hardwood should work just fine. Just take the measurements from a couple of well built instruments for reference. I'm amazed how thin bass necks can be despite being so much longer than guitar necks!

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I'd have to agree with you on thin necks on a bass. My budget bass I got as a child is probably no thicker than my father's Martin acoustic guitar! That said, with this bass project I hope to have a similarly thin neck, or at least less of a curvature at the back.

The graphic you posted is interesting. Though I'm sure the short scale length (only 4" longer than the aforementioned Martin guitar, funny enough) will mitigate the risk of twisting, it's good information to have!

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I'm no expert bass builder but I'm a good third of the way into my first bass build (also neck through) and I've built a fair few guitars and the principles are the same. 

Start off drawing a full scale plan, including drawing on the fret slots, bridge position, turner holes etc. That will give you all the information you need for the end of the fretboard and tell you how much space you have for the pickups. Also with any neck-through design, do as much as you possibly can on the neck before you glue the wings on. It's a very long piece of wood so drilling tuner holes in a drill press is awkward even without the body glued on. I've just finished inlaying my fretboard and I'll get it fretted and the neck at least rough carved before I glue the wings on. 

In terms of neck thickness, I was surprised that bass necks are actually often smaller than a lot of guitar necks. The one I'm working on has the taper of a musicman bongo 4, so it's only 41mm wide at the nut. A friend of mine as a 90s warrick which is even thinner at 39mm at the nut. So you can probably get away with as little as 43mm at the nut for a 5 string. If you want to reduce the thickness of the neck, you can always make the fretboard slightly thinner to allow you to keep more wood under the truss rod. But that is all stuff you can work out with a full scale plan.

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as mentioned by many I'd def work off of some sort of plan - a lot of your fretboard length questions can be answered (with no math!) via the 'fret2find' portlet here on the forum.  Its a browser app that will calc out fret sizes ect and create a pdf/jpg.  I'd start there... create an image of your fretboard and build the body around it.  I've build a 32" scale bass, and it's awful comfy compared to a 34... a 30 should be pretty small.  I don't think reinforcement would necc be required given such a short scale... but it probably doesn't hurt. 

I would think your big hurdle is going to be 30" scale + low b string - she is going to be very low tension.  at that point you start thinking about really high gauge strings and we're back to needing reinforcement.

anywho... welcome aboard!

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16 hours ago, ADFinlayson said:

If you want to reduce the thickness of the neck, you can always make the fretboard slightly thinner to allow you to keep more wood under the truss rod.

It's funny you mention it, I was thinking about having a (near) infinite radius on the fretboard, so I could easily take some thickness out of the board for that, I think.

14 hours ago, mistermikev said:

I would think your big hurdle is going to be 30" scale + low b string - she is going to be very low tension.

I'm aware they make bass strings for short scale lengths to compensate, presumably by requiring more tension than standard strings. That said, if they dont make a B string that way it'll be a fun hurdle to jump over 

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Just as a side note: The first few builds tend to have necks like a baseball bat rather than too thin. There's exceptions, one guy managed to destroy a couple of blanks for his first build by carving through the single action truss rod channel. As a dual action rod only takes 9 mm under the fretboard that should not be any concern using one.

Also, as you said you'd be making it a through-neck I suppose you'd be laminating the neck from several pieces which will further add stiffness and strength even without carbon fibre reinforcements.

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Hi, @TheRavenOfDiscord and welcome!

Excellent - another bass builder! :)

Although I am personally a guitar player more than a bass player, I have certainly built more basses than 6-string electrics and most of those have been through-necks.  In fact, all of my full bass builds have been through necks - although I have made bolt-on neck replacements for 4, 5 and 6 string basses.

You talk about 30" being relatively rare.  Well, certainly in the UK it used to be, but here there is a growing realisation within a lot of bass players that, nowadays, you can get just as good a sound from 30" basses, you can get great strings for them and they are MUCH easier to play than a 'standard' long scale.  It is interesting that nowadays, I get more enquiries for short scale than I do for long scale...

 

There is a lot of wisdom already expressed in the above replies.  Re-iterating some of those answers and adding a few of my own:

- The end of your fretboard is going to be around 23" from the nut, leaving you 7" for your pickups.   That's plenty.  Are you going Jazz pickups or P-type? or PJ? 

- I build my guitar necks and bass necks to the same thickness.  It usually ends up at around 21mm /22mm at the 1st fret (spine to top of fretboard) rising to around 23mm at the 12th.  That is usually with a max thickness of 6mm fretboard, so it breaks down at 6mm fretboard + 11mm trussrod & trussrod cap slot which leaves me a minimum of 4mm/5mm timber underneath the trussrod

- I don't fit carbon fibre reinforcement rods for 4 or 5 string basses unless specifically asked.  I do add rods for a 6 string bass

- I usually do a 3-laminate neck with the middle one being a 6mm splice.  5-piece laminates are great and I have done them at times, but I've never had a warp or twist issue with a 3-piece.  However, I always use quality timber from trusted sources for the necks.  I'm usually happy to use any structurally-sound timbers for the body!

- I fit a single, good quality 2-way trussrod.  I personally think you can introduce more problems by fitting two trussrods than solve them.  If the neck wood is straight, tight grained, properly seasoned and in the right grain orientation, and the fretboard likewise is a decent hardwood and flat, there should not be any warp issues in normal use and storage. 

 

One last tip.  With a through neck, remember that any neck angle needs to be built into the neck before the body is built onto it.  Therefore you need to know what bridge you are going to use up front so that you can sort the geometry correctly.  Personally, I physically get hold of the bridge first and check the ACTUAL adjustment ranges and then draw the nut/fretboard/bridge lines full size to work out the angle I need to build into the neck blank.

Very much looking forward to seeing your build develop!

Andy

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7 hours ago, TheRavenOfDiscord said:

 

I'm aware they make bass strings for short scale lengths to compensate, presumably by requiring more tension than standard strings. That said, if they dont make a B string that way it'll be a fun hurdle to jump over 

that's the spirit.  there's a lot of talk on various forums of guys sayin' "you gotta have a 35" sl for a lob B.  I have a 35 and a 34 and to me... I sorta like it floppy on the 34 altho admittedly you get more fret rattle - even with extra thick strings.  I also like my action super low tho so perhaps that's not as much of a problem for others.

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On 1/3/2020 at 4:06 AM, Andyjr1515 said:

Personally, I physically get hold of the bridge first and check the ACTUAL adjustment ranges and then draw the nut/fretboard/bridge lines full size to work out the angle I need to build into the neck blank.

 

I was looking at bridges last night and 1) holy cow are the hotshots I looked at surprisingly expensive for what looks like a simple piece of metalwork, and 2) the angle of the neck is largely dependent on the bridge height and the kind of action I want on the fretboard, yes? My ideal would be to have the action such that it quite easily facilitates a good clean slapp without taking too much effort to fret. Yet another fun hurdle to tackle, I suppose. 

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9 hours ago, TheRavenOfDiscord said:

 

I was looking at bridges last night and 1) holy cow are the hotshots I looked at surprisingly expensive for what looks like a simple piece of metalwork

There are some very expensive bridges.  I rarely fit them, even on very expensive basses.  There are a host of excellent and affordable bridges around ;)

9 hours ago, TheRavenOfDiscord said:

2) the angle of the neck is largely dependent on the bridge height and the kind of action I want on the fretboard, yes? My ideal would be to have the action such that it quite easily facilitates a good clean slapp without taking too much effort to fret.

Yes - basically.  When I do my drawing, I take the height of the bridge with the saddles at their lowest position and aim for a string, riding all along the tops of the frets to be able to sit at that height.  That is, I want to be able to lower the saddles on the finished bass to the point that the strings touch the frets.

  On my own drawings, I drop that a mm or two lower still to allow for the effect of relief and to allow for the vagaries of the build.

I then draw a line from the nut to the highest position the saddles will go and see what the maximum action height would be at, say 12th fret and 15th.  If that is greater than my preferred action height, then I know that the adjustment range of the finished bass will be able to get to as low as I could possibly want and as high as I could possibly want.

I have a photo of one of my drawings somewhere - I'll try and track it down...might make a bit more sense :)

 

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