Need help making saddle

[Ned Milburn]

Originally Posted by charles Tauber

I think Todd's point is that when one can set the string height of each string, such as on a Telecaster bridge, no consideration is given to "fingerboard radius". Each string height is as it needs to be.

A similar approach can be used on a non-adjustable saddle, setting each string height as it needs to be, regardless of fingerboard radius.




That works well provided that the amount that needs to removed is either uniform for all 6 strings, or a linear amount - i.e. accomplished by tapering the height from the bottom along a straight line. It doesn't work when the string heights need to be varied/corrected individually, which is often the case. Then add in the often-seen need to adjust the amount of compensation for each string - within the limits of the width of the existing saddle - and you may as well make the changes from the top.

In short, its a case-by-case situation. Do what works best for the situation with which you are presented.

Fair enough. Well stated.

[Tony Done]

Originally Posted by Todd Yates

Tony, that will work too, and obviously you're happy with the results. However, I think you've put more emphasis on fretboard radius that necessary. I never consider the radius of the saddle.

I know how high I want the strings at the 12th fret and I cut the saddle down until I get there. If you're staggering the strings so that the high E is the lowest (say 0.080") and the low E is the highest (say 0.095") the four strings in the middle will be at progressive heights between those two numbers.

Think about a modern Telecaster or Stratocaster bridge. You really don't worry about the fretboard radius there. You adjust each saddle individually. An acoustic guitar is the same expect we make a smooth curve on top of the saddle to "connect the dots".

I also adjust everything from the top. Once the saddle is fitted to the bottom of the slot, I don't mess with it again. Probably from my tinkering with long saddles, but it works on short saddles too. It's counterproductive if you're using a pre-compensated blank, I suppose, but I start with plain blanks.

And Ned and Charles.

I do Fender saddles by getting the 1st and 6th strings right, then eyeballing the rest. - it includes looking across the strings at the bridge to see the evenness of curvature; any irregularities are very obvious.

Acoustic saddles seem to be just simple geometry to me on a fixed-radius board with properly leveled frets, and I can't see any reason why the saddle shouldn't have the same radius as the board, or strictly speaking, the fret crowns. Assuming the 1st and 6th strings are where you want them, then:

Having a greater saddle radius will make barres more difficult than they need to be, and

Having a shallower radius could lead to fret rattles on the inner strings.

So I get the radius right, then remove stock from the bottom of the saddle to get the bass and treble height right. - I use the vise jaws as a stop to get most of it off, then finish it by rubbing on a flat (they sometimes aren't) file.

If I'm missing something here, I would be glad to know it for future reference.

FWIW, my saddle radiusing jig consist of a stiff flexible strip - I use a power hacksaw blade - with coarse sandpaper stuck to one side. I clamp one end to the bench, sandpaper side up, then use a wood block to ramp up the free end until it is the correct concave for the saddle radius, as measured with the old saddle, or (homemade) concave and convex radius gauges. Then it is just a case of scrubbing the top of the saddle on the sandpaper until it is radiused.

I do intonation by having one front-to-back slant for the first two strings and another for the other four.

[charles Tauber]

Originally Posted by Tony Done

If I'm missing something here, I would be glad to know it for future reference.

I've discussed this at length before, so I'll only mention it briefly now. In short, as I do it, the fingerboard radius is irrelevant. I want each string to be the height I want it to be. I accomplish that, in part, by adjusting the saddle height for each string. It doesn't then matter what the fingerboard radius is. The contour of the top of the saddle will be whatever produces those string heights.

I do intonation by having one front-to-back slant for the first two strings and another for the other four.

I want the intonation better than that will generally achieve. To do so, I compensate each string individually: each string breaks over the saddle where the intonation dictates it needs to be, not by how many chamfers I arbitrarily chose to put on a saddle. That's how I do it: others do it differently. Whatever get the results you want is best.

[Tony Done]

Originally Posted by charles Tauber

In short, as I do it, the fingerboard radius is irrelevant. I want each string to be the height I want it to be.

OK, I'm curious to know why you wouldn't want a linear progression in action height from the 1st string to the 6th. Just as an example - 1.6mm, 1.8, 2.0, 2.2, 2.4, 2.6mm. - Which is what my method yields.

If this has been discussed before, do you have a link please. I'm genuinely interested to know the arguments surrounding this.

[charles Tauber]

Originally Posted by Tony Done

OK, I'm curious to know why you wouldn't want a linear progression in action height from the 1st string to the 6th. Just as an example - 1.6mm, 1.8, 2.0, 2.2, 2.4, 2.6mm. - Which is what my method yields.

I do want a graduated string height.

Any way you achieve that is fine. I just don't do it by trying to relate the radii of two curves. To achieve the graduated heights you describe, the radius of the top of the saddle cannot be the same radius as the fingerboard. Generally, the curvature of a fingerboard is the surface of a cone, rather than a single radius cylinder. With a conic, which radius are you trying to match? The radius at the first fret? The 12th fret?... The further up the fingerboard you go, the larger the radius. By the time you project that to the saddle location, it is larger still. And, that doesn't account for the graduated string heights. Those are achieved by "tilting" one radius relative to another.

It's geometry.

If this has been discussed before, do you have a link please. I'm genuinely interested to know the arguments surrounding this.

There's no argument. There are a variety of way to achieve a desired result, and with each a theory of how/why it works. Pick one you like. Taking direct measurements of string height works for me and is simple. I don't need to be concerned with radii or gauges to measure radii. All I need is one ruler. Lots of people do it as you describe - look at the number of radius gauges sold.

The Stratocaster bridge is a good model. There are 6 individual saddles. Each is adjusted until it produces the desired string height. No thought is given to any radius. They form 6 independent, steps.

If you eliminate the height adjustment from each of the Strat's saddles, glue them together side-to-side, you have an acoustic guitar saddle. You have one saddle with 6 individual, discrete steps in its height. There is no curvature. Each of the 6 steps provides the string height desired for the individual string it supports. There is no curvature. There is no radius. There is no spoon - oops, got carried away. The 6 points of intersection between each string and where it crosses the saddle can be joined by a smooth curve (i.e. Bezier). It won't be a curve of a constant radius, but, rather one of multiple radii. Can that be approximated by a single radius curve, sure, if you want to. I see no need to.

Here's what one of my saddles typically looks like:



Here's what happens with the break points for a fully compensated saddle:

[Tony Done]

Originally Posted by charles Tauber

I do want a graduated string height.

Any way you achieve that is fine. I just don't do it by trying to relate the radii of two curves. To achieve the graduated heights you describe, the radius of the top of the saddle cannot be the same radius as the fingerboard. Generally, the curvature of a fingerboard is the surface of a cone, rather than a single radius cylinder. With a conic, which radius are you trying to match? The radius at the first fret? The 12th fret?... The further up the fingerboard you go, the larger the radius. By the time you project that to the saddle location, it is larger still. And, that doesn't account for the graduated string heights. Those are achieved by "tilting" one radius relative to another.

It's geometry.



There's no argument. There are a variety of way to achieve a desired result, and with each a theory of how/why it works. Pick one you like. Taking direct measurements of string height works for me and is simple. I don't need to be concerned with radii or gauges to measure radii. All I need is one ruler. Lots of people do it as you describe - look at the number of radius gauges sold.

The Stratocaster bridge is a good model. There are 6 individual saddles. Each is adjusted until it produces the desired string height. No thought is given to any radius. They form 6 independent, steps.

If you eliminate the height adjustment from each of the Strat's saddles, glue them together side-to-side, you have an acoustic guitar saddle. You have one saddle with 6 individual, discrete steps in its height. There is no curvature. Each of the 6 steps provides the string height desired for the individual string it supports. There is no curvature. There is no radius. There is no spoon - oops, got carried away. The 6 points of intersection between each string and where it crosses the saddle can be joined by a smooth curve (i.e. Bezier). It won't be a curve of a constant radius, but, rather one of multiple radii. Can that be approximated by a single radius curve, sure, if you want to. I see no need to.

Here's what one of my saddles typically looks like:



Here's what happens with the break points for a fully compensated saddle:

Thanks. I like your diagram of saddle compensation; the whole thing is more effective with the wide saddle that you use, there isn't much latitude on a Martin saddle. I'm not at all sure that my method is anything more than cosmetic - but it at least looks like I've tried. I just checked my Maton (which has my saddle), while writing this, with my very basic Planet Waves Micro tuner. It seems to be spot on , and an open E chord fretted at the 13/14 frets sounds pretty good.

I've always thought of boards and saddles as cylinders, eg 15" all the way, except for compound radius boards which I would treat as a cone. However, it isn't as easy as that because if you were going to very small tolerances, the difference in string width between the nut and saddle - the string aren't running parallel to the cylinder. That would also have an effect on how I would treat the saddle curvature if I could get my head around the geometry of it.

[Ned Milburn]

Originally Posted by Tony Done

So I get the radius right, then remove stock from the bottom of the saddle to get the bass and treble height right. - I use the vise jaws as a stop to get most of it off, then finish it by rubbing on a flat (they sometimes aren't) file.

I think we are on the same page. Shape saddle radius (top), then fine tune the height by removing stock from the bottom.

All good! Must'a'been just the way we was talkin' was makin' us sound like we was sayin' diff'rent things, but we was actually sayin' the same thing. ;-)

On more reason that I use the "top down" approach is that much of my tinkering is applied to old Martins and Gibsons with long, glued-in saddles. Lowering from the bottom is not an option, since the wings would no longer match the bridge. I've done so many from the top that it just seems the more natural thing to me now, and it gives me complete control of individual string height as Charles described.

[charles Tauber]

Originally Posted by Tony Done

... if I could get my head around the geometry of it.

And, that's my point. You don't have to. Use the height of each individual string to tell you what the saddle contour should be.

[joeguam]

It seems this thread is in some real good company of luthiers, awesome.

With the consideration that the slot for each string at the nut is filed and cut-to-depth individually based on it's relative height to the first fret (this is correct right?), my question is, why isn't the saddle made in exactly the same way? Some eluded to shaving the saddle and compensating it individually, but my question takes it a step further: why don't luthiers file slots in the saddle for the strings like what is done at the nut?

[Tony Done]

Originally Posted by charles Tauber

And, that's my point. You don't have to. Use the height of each individual string to tell you what the saddle contour should be.

............................

[123john]

Wow, what a bargain...I asked for Saddles 101 info but ended up getting the full Ph D. dissertation! Thanks again all!! But it will take me some time to digest it all, that's for sure. Why can't acoustic saddles be like electric saddles? No sanding or filing needed there, just an allen wrench and a screwdriver and you have infinite adjustment at your disposal. I think I recently saw an acoustic guitar (probably on ebay) with an electric type bridge, but can't remember what it was.

[Ned Milburn]

Originally Posted by 123john

Wow, what a bargain...I asked for Saddles 101 info but ended up getting the full Ph D. dissertation! Thanks again all!! But it will take me some time to digest it all, that's for sure. Why can't acoustic saddles be like electric saddles? No sanding or filing needed there, just an allen wrench and a screwdriver and you have infinite adjustment at your disposal. I think I recently saw an acoustic guitar (probably on ebay) with an electric type bridge, but can't remember what it was.

Some people have come up with ingenious gizmos, including releases of screw-adjustable saddle heights by Gibson and others, but nothing seems to improve significantly over a standard bone saddle in regards to its utility, stability, ease of manufacture, and quality of tone.

Originally Posted by 123john

...Why can't acoustic saddles be like electric saddles? ...

The biggest issue with most adjustable systems is weight, as in too much compared to a simple piece of bone in a slot.

[Rodger Knox]

Originally Posted by joeguam

It seems this thread is in some real good company of luthiers, awesome.

With the consideration that the slot for each string at the nut is filed and cut-to-depth individually based on it's relative height to the first fret (this is correct right?), my question is, why isn't the saddle made in exactly the same way? Some eluded to shaving the saddle and compensating it individually, but my question takes it a step further: why don't luthiers file slots in the saddle for the strings like what is done at the nut?

Because that frequently causes a buzz. At the nut, there's a greater distance to the anchor point (the tuning peg), so some slotting is necessary to keep the string in place. There can be buzzing associated with nut slots that aren't cut precisely enough.
At the bridge end, the distance to the anchor point (the bridgepin) is small enough that slotting the saddle is unnecessary, and since it frequently causes problems, it is seldom done. Archtops with tailpieces are a different story, some builders do slot the saddle on archtops.(Not usually as deeply as the nut is slotted)