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Posts: 94
Reply with quote  #1 
I think about guitar hardware design a lot and am interested in headless hardware, linear-pull tuners and height/intonation-adjustable per-string nuts.
I have an idea for tap guitars where the open notes are never used due to the use of a string damper.

Imagine hardware slightly similar to this ...


... mounted at the headstock end of a tapguitar such that these saddles act as the nut for each string.

Imagine a string clamp mounted on the top of the rectangular saddle, such that the string passes over what is now the nut and immediately into the string clamp.
What was the intonation screw is now the tuner and pulls the nut and string clamp backwards to tension and tune the string.
The saddle height adjustment screws provide the 'height adjustable nut' that is so useful for a tap guitar.

The reason this works for a tap guitar is because the open note is never played, so the linear position of the nut is not important for intonation, therefore the nut position is now free to move to tune the string.

* Compactness in terms of instrument overall length.

* Combining a tuner and height adjustable nut into a single simple mechanism.

* Ability for a bass scale tap guitar to use cheap and common guitar strings:
Many guitar strings (for example D'Addario) have a winding length long enough to be usable on a bass scale, however their overall length is not long enough to reach the tuner posts.
They are long enough however to pass into a string clamp just behind the nut.

* Ability to use standard bridge hardware for the bridge of the tap guitar instead of expensive and rare headless hardware.

* Tuning stability:
On a normal fixed bridge guitar, significant tuning instability is caused by having a length of string between the nut and the conventional tuner. Bending a string pulls the string slightly over the nut, then it does not slip fully back due to nut friction, leaving the pitch flat. This is why a guitar equipped with a Floyd Rose tremolo bridge has a 'locking nut'.
With my design, there is near-zero distance between nut and string clamp so this problem does not occur, it acts just like a locking nut.



I've decided to attempt to licence the design ideas in this thread with the intention of keeping them forever freely usable by anyone.
I don't want to see anyone patent or trademark this for themselves or restrict it in any way.

The license for this design is:
Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)

For attribution, the name of the creator is 'ixlramp'.


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Posts: 94
Reply with quote  #2 
Concerning string clamps, i'm not too happy with the standard clamp used in headless hardware: a channel with a wide grub screw that clamps the string.

As the grub screw clamps down hard on the string it also rotates, which seems to me to have some problems:

* For wound strings, the rotation could possibly 'unwind' and loosen the outer layer of wrap wire a little, which can ruin the tone of a string.
* For plain steel strings, which can be thin and fragile, the rotation of the grub screw has more chance of damaging or even cutting the string.
* The section of string underneath the grub screw can rotate to no longer be in line with the rest of the string. This creates a less solid anchor and a non-ideal bend in the string. The string tension wants to reverse this rotation, if it does it will also try to rotate the grub screw in a way that loosens it.

I quite like the idea of a non-rotating grip plate, as used by Kelstone on their 'headstock'-mounted linear-pull tuners:


The string passes between the 2 screws.
The 2 gripping surfaces tend to be flatter than the tip of a grub screw.
There is more surface area to grip the string, instead of just the width of the grub screw.

Big George Waters

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Posts: 114
Reply with quote  #3 

The KYDD upright electric basses use something similar - but it' s opposite at the same time:

They use a bridge tuner that is very similar to what you are thinking - and at the nut end, a good old fashioned locking nut - hence any kind of strings can be used on their 34" scale model

I am a huge fan of these instruments, huge fan.... it's a very brilliant but at the same time simple design.


Of course you do not get the height adjustment - on the other hand, I would think running a "zero" fret between the mute and the locking nut would solve any height issue.

Of course, I could be wrong on that....

Food for thought if nothing else.


I like hearing when people are thinking of designing things.

*unrelated - but I spent all morning trying to figure out how to make a strap system which would enable a Stick player to play sitting down - where the strap goes through the belt clip.

 I am very close with a very pratical cheap solution on that............



Big George W

           East Derby CT

Mobius Megatar - tuned in Classic Stick Tuning [5ths/4ths]

M.Megatar Toneweaver - tuned in Major 3rds

Warr Phalanx 12 - tuned in 5ths [melody], 4ths [bass]

NS Stick Transparent Green w/Moses graphite neck, tuned in 8-string Guitar Intervals

digitech, T.C. Electronics, ART, Lexicon, GK, Markbass, EA, Bag End, Guild/Hartke, SWR, EV, Radial, Ampeg, Trace Elliot, Furman




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Posts: 23
Reply with quote  #4 
All good ideas! ... Someone just needs to try them out and iron out the little practical issues.
I'm not 100% convinced that the threads on some standard brands of saddles and their screws would work nice and smoothly for tuning . Ideally the philips (or slotted) screws could be swapped out for allen heads I guess ... and you'd have to go round with an Allen wrench for tuning or else adapt for some other 'tool-less' method.
...just thinking out loud

Patagonia, Argentina

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Posts: 94
Reply with quote  #5 
I agree, that guitar bridge is just used to help visualise new dedicated hardware, i don't suggest a modified guitar bridge. Most guitar saddles and intonation screws are made from cheap materials and are not designed to withstand string tension.
Hex key socket-cap screws would be compact and lightweight, or maybe staggered knobs (staggered to maximise their size).

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Posts: 94
Reply with quote  #6 
Thinking about width:

At first i was thinking to make these 8mm wide, as a 8mm string spacing seems suitable for many tapguitars. It seems many tapgutars use a guitar string spacing, which is 10.5mm at the bridge and as little as 7mm at the nut (both stated centre-to-centre). 7mm is quite narrow, considering that tapping requires a little more room than fretting, and the fact that tapguitars often use large gauges up to around .125, 8mm seemed a good choice.

However, with this design, the maximum gauge string is determined by not obstructing hex key access to the height adjustment screws, there is not much room between them.
At first i thought that a 8mm width could be used and the string clamp could be mounted away from the height adjustment screws, such that if access was partly blocked the string could be detuned and pulled sideways. However, detuning a string to adjust saddle height will be irritating and time consuming.

Measuring up a standard 10.5mm wide guitar saddle while 2 1.5mm hex keys are inserted into the height adjustment screws:
The screw centres are 6mm apart, 2.25mm in from saddle edges. The minimum gap between the hex keys is 4mm, which is string gauge 0.157, plenty big enough for even very low tunings.
My personal preference is parallel strings and 10.5mm spacing, but i like large string spacing.

With a 8mm wide saddle and the screws moved outwards slightly (if possible) to be 2mm in from saddle edges, the gap would only be 2mm which is string gauge .079, not big enough for many tapguitar tunings.

A compromise of 9.5mm (screws not moved outwards) would create a gap of 3mm, string gauge 0.118 which is just big enough for a bass low B and most tapguitar tunings.

One possibility is that various widths could be machined and used together in the same way that bass guitars have string spacing increasing for the larger lower gauges, to preserve 'centre-to-edge' spacing.

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Reply with quote  #7 
I realised that this hardware can be used at both ends of a string, simplifying manufacture of an instrument.
At the bridge end, the hardware is moved horizontally to intonate the string. At the 'nut' end it is moved horizontally to tune the string.

Advantages as a bridge
* Tuning stability:
The string passes over the saddle and immediately into a string clamp, a little like a Floyd Rose tremolo gutar bridge.
Because there is no longer a 1"-2" length from saddle to ferrule anchoring point, tuning stability is increased.

* Positioning of taperwound strings:
With conventional bridges, taperwound strings often have an unoptimally-long length of tapered section in the vibrating length, which causes inharmonicity. It is optimum for the tapered section to be very short.
A string clamp allows the string to be shifted through the bridge and into an optimum position.

* Ferrule size becomes irrelevant:
Guitar strings, bass strings, loop-end plain steel strings, strings without attached ferrules, all become usable because the anchoring is now done by string clamp, not by the anchoring of a ferrule.

* The sharp bend where the string passes over the saddle doesn't move along the string when adjusting intonation.
When setting up an instrument, the correct saddle intonation offset is guessed and can only be corrected once the string is tuned up, but tuning up creates a bend in the string at that incorrect position. Once intonation is corrected, bends have been formed in the string either side of the saddle, which is not optimal.

* The 'bend angle' of the string over the saddle is fixed and independent of saddle horizontal or vertical position.
For example, with a standard bass bridge, the B saddle is far further back than the G saddle, and set higher, the result is significantly differing bend angles, causing differing amounts of downforce.

Required strength
Just as with the 'nut' end usage, this hardware will have to be stronger than the typical guitar saddle, as it and the intonation screw now support the tension of the string.
The tension force of the string is also not aligned with the screw. The line of the tension force has to pass above the screw anchoring point to create a torque to generate the usual downforce on the saddle. This will create extra stress on the screw.
So, the screw will probably have to be beefed up to a M4 instead of the standard M3 intonation screw.
The body of the saddle will have to be strong, no cheap and nasty 'pot metal' as many saddles are.

For guitars too
This bridge design can be used for normal guitars too, as long as they have tuners on the headstock, all the advantages remain.
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