Uneven Saddle Sanding

[Rodger Knox]

Originally Posted by murrmac123

IMHO, it's high time time that the "lay a straightedge along the frets and see where it contacts the bridge " approach was consigned forcefully to the dustbin of history.

+1 !
It's a quick way to check the neck angle, but it's only good if there's no string tension on the neck. It's very useful when building, before you can put strings on the guitar.

If you can put strings on the guitar, the action height, the height of the strings above the soundboard, and amount of saddle above the bridge tell you all you need to know about neck angle.

[skitoolong]

Originally Posted by Rodger Knox

+1 !
It's a quick way to check the neck angle, but it's only good if there's no string tension on the neck. It's very useful when building, before you can put strings on the guitar.

If you can put strings on the guitar, the action height, the height of the strings above the soundboard, and amount of saddle above the bridge tell you all you need to know about neck angle.

I cannot tell you how many resources, forum messages, Youtube, etc that I have read over the last few weeks advising on the straightedge as a useful tool for checking neck angle.

I did this to evaluate a guitar that I evaluated recently. Yes, I bought it because the measurements I took were within the tolerances that my research deemed acceptable.

Not pleased.

[murrmac123]

Originally Posted by skitoolong

I cannot tell you how many resources, forum messages, Youtube, etc that I have read over the last few weeks advising on the straightedge as a useful tool for checking neck angle.

Indeed they do. And they are wrong, because when you do this you are not measuring the neck angle. The neck terminates at the neck/body joint ... beyond that is the fretboard extension, which has no relevance whatsoever to neck angle, and will give a false reading if there is a rise in the fretboard extension.

As Roger said, the straightedge is an essential tool in building a guitar, but when it comes to assessing an instrument which has been around the block a few times, the straightedge is irrelevant. Saddle height, string height above soundboard, action at 12th fret, these are the only parameters you need to worry about. And these measurements btw are also the only variables you need in order to figure out how much to remove from the heel when doing a reset.

[skitoolong]

Originally Posted by murrmac123

Indeed they do. And they are wrong, because when you do this you are not measuring the neck angle. The neck terminates at the neck/body joint ... beyond that is the fretboard extension, which has no relevance whatsoever to neck angle, and will give a false reading if there is a rise in the fretboard extension.

As Roger said, the straightedge is an essential tool in building a guitar, but when it comes to assessing an instrument which has been around the block a few times, the straightedge is irrelevant. Saddle height, string height above soundboard, action at 12th fret, these are the only parameters you need to worry about. And these measurements btw are also the only variables you need in order to figure out how much to remove from the heel when doing a reset.

So, if I was careful (and I was) in observing that the fretboard extension did not influence the path of the straight edge, I still contend with the fact that the guitar neck is under load, and a "more" correct indication would be sans strings?

And absent all that, I only need to consider the three parameters you discuss. I wonder if you would be so kind as to indicate the acceptable values for saddle height?

[stanron]

Surely the straight edge method is OK so long as you have removed relief from the neck and also used it to check the flatness of the fretboard.

[arie]

Originally Posted by skitoolong

So, if I was careful (and I was) in observing that the fretboard extension did not influence the path of the straight edge, I still contend with the fact that the guitar neck is under load, and a "more" correct indication would be sans strings?

And absent all that, I only need to consider the three parameters you discuss. I wonder if you would be so kind as to indicate the acceptable values for saddle height?

here, let someone with actual working experience help you:

http://www.frets.com/FretsPages/Musi...neckangle.html

read this. if your guitar meets or fails these criteria you now have a place to start.

[murrmac123]

Originally Posted by skitoolong

So, if I was careful (and I was) in observing that the fretboard extension did not influence the path of the straight edge, I still contend with the fact that the guitar neck is under load, and a "more" correct indication would be sans strings?

No, once the guitar has been built and strung up and time has had its way with the tension on the neck, the only meaningful measurements are those taken with the guitar tuned up to pitch. Assessing with the strings off is ineffectual at this point.

Assessing the neck angle with a straight edge when the guitar is in the process of being built is a best guess as to how the instrument will behave when strung up to tension. It may well have a perfect neck set to start off with, but over time, as often as not, the body will distort under tension, and the neck angle changes.

Originally Posted by skitoolong

And absent all that, I only need to consider the three parameters you discuss. I wonder if you would be so kind as to indicate the acceptable values for saddle height?

Saddle height should be considered only as part of the equation, in conjunction with the bridge height and the height of the strings from the soundboard. The main caveat is that the saddle should not be so high that the strings exert an undue leverage on the saddle with the possibility of damaging the bridge. Most would say that 3/16" above the bridge would be the very maximum in this respect. I have a John Slobod OM which has this projection, and it sounds great, but I wouldn't want it any higher.

So basically, bridge height + saddle projection should be ≤ .5", and ≥ 7/16".

[skitoolong]

Originally Posted by arie

here, let someone with actual working experience help you:

http://www.frets.com/FretsPages/Musi...neckangle.html

read this. if your guitar meets or fails these criteria you now have a place to start.

I'm well aware of that particular piece. In fact I used it for reference. Unfortunately I'm learning that the straight edge is less than useful.

[murrmac123]

Originally Posted by stanron

Surely the straight edge method is OK so long as you have removed relief from the neck and also used it to check the flatness of the fretboard.

Well, what exactly is the straight edge method ? By which I mean, you lay the edge along the frets, and you get a reading as to where it contacts the bridge, right? So where does it go from there ? Can someone detail the process after that, using the straight edge reading, to arrive at the numbers required to fix the action ?

[John Arnold]

IMHO, if you can measure the action, the saddle height, and the bridge thickness, you don't need to do the straightedge check. In fact, about the only time I use it is during a neck reset, just so I have a reference point. That way, I can judge the change in angle after trimming the heel, but before it is glued in.

The 1/2" string height reference is assuming a bridge thickness of about 11/32" (0.344") and a maximum saddle height of 0.156". If the bridge is thicker or thinner, then you must take that into account. I don't like to see saddle heights above 0.160" on a Martin style bridge, because the high break angle across the saddle can cause it to lean. It is the main reason bridges crack through the saddle slot.

[Ned Milburn]

Originally Posted by skitoolong

So, if I was careful (and I was) in observing that the fretboard extension did not influence the path of the straight edge, I still contend with the fact that the guitar neck is under load, and a "more" correct indication would be sans strings?

Only if you play your guitar without strings. ;-)

The others have put some good info in this thread. My input at this point is comic relief only. Apologies for the self indulgence. :-D

[skitoolong]

I decided to use all my newfound wit to bear upon lowering the action last night.

The first thing I noticed upon close inspection is that the saddle is unlike the saddle on my Taylor, Breedlove, or Walden. It simply has a uniform radius across the top, and no offset for any of the strings. I think that is termed "Uncompensated?".

Now there is something new to learn about. Why is this guitar different?

Anyway, I traced and made a little template of the saddle radius, then transferred that radius back onto the saddle taking off what my figuring deemed necessary on the low E and the high e side. There was very little taken off the high e and probably 3/64th taken off the low E.

I sanded to my line following my radius template, and remade the curve across the cross section of the saddle, reinstalled, restrung, and voila. Around 3/32 under the low E and slightly less under the high e with sufficient break angle across the strings.

It plays very very well now and sounds wonderful. I'm quite happy with how it turned out.

I just need to understand this business about saddle compensation now.

Thanks everyone for your generous information!

[John Arnold]

Saddle compensation is about getting better intonation on all the strings. There is no straight saddle that will produce perfect intonation on all the strings. This is primarily because plain, unwound strings behave differently than wound strings. Therefore, in theory, a straight saddle will not produce as accurate intonation as a properly compensated one. But the difference is very slight, and if the straight saddle is placed properly, it rarely becomes an issue.

[skitoolong]

Originally Posted by John Arnold

Saddle compensation is about getting better intonation on all the strings. There is no straight saddle that will produce perfect intonation on all the strings. This is primarily because plain, unwound strings behave differently than wound strings. Therefore, in theory, a straight saddle will not produce as accurate intonation as a properly compensated one. But the difference is very slight, and if the straight saddle is placed properly, it rarely becomes an issue.

Thank you. I think I'm going the route of "if it ain't broke don't fix it"