Quizical about Vernier Caliper Use

[RedJoker]

Originally Posted by mirwa

Its nice when people come along and talk about nothing to do with the topic at hand, simply semantics about a descriptive.

Why do people do this?

We could argue such a mute point all day long, but it has nothing to do with the topic at hand, so why even raise said topic.

Maybe you should contact manufacturers who are selling new products and inform them of how incorrect they are and how they are corrupting society's way of thinking.

Steve

This post made me chuckle.

I hope you have a good day!

[bausin]

>> We could argue such a mute point all day long, but it has nothing to do with the topic at hand, so why even raise said topic.

Shouldn't that be a MOOT point? :-)

[tadol]

But the point of most of these threads, especially in the build and repair area, is to offer knowledge, and to correct misconceptions, and the use of incorrect terminology should be corrected, gently, and when links can be provided for those more interested in advancing their knowledge within context, I am actually thankful -

The nice thing about posts on a computer forum is you can scroll past the ones you find uninteresting - quite easily -

[bausin]

Originally Posted by mirwa

Its nice when people come along and talk about nothing to do with the topic at hand, simply semantics about a descriptive.

Why do people do this?

We could argue such a mute point all day long, but it has nothing to do with the topic at hand, so why even raise said topic.

Maybe you should contact manufacturers who are selling new products and inform them of how incorrect they are and how they are corrupting society's way of thinking.

Steve

Your reply has nothing to do with the topic at hand. Why did you do it?

Steve

[Big Band Guitar]

Originally Posted by mirwa

Its nice when people come along and talk about nothing to do with the topic at hand, simply semantics about a descriptive.

Why do people do this?

We could argue such a mute point all day long, but it has nothing to do with the topic at hand, so why even raise said topic.

Maybe you should contact manufacturers who are selling new products and inform them of how incorrect they are and how they are corrupting society's way of thinking.

Steve

There are no manufacturers listing a digital caliper as Vernier digital or digital Vernier.

[Rodger Knox]

Originally Posted by tadol

But the point of most of these threads, especially in the build and repair area, is to offer knowledge, and to correct misconceptions, and the use of incorrect terminology should be corrected, gently, and when links can be provided for those more interested in advancing their knowledge within context, I am actually thankful -

The nice thing about posts on a computer forum is you can scroll past the ones you find uninteresting - quite easily -

That bears repeating.

[arie]

Originally Posted by ChrisN

I see nothing on the side that might be what you're talking about - just the screw-down thumb wheel to lock it in place.

I figured if the bottom of the depth rod was squared off and applied squarely against a squared-off bridge top, while the caliper's body (also squared off) was applied to the top of the saddle, then I should be able to achieve repeatable measurements, but it was not to be.

the left side is where the fixed anvil is, the lock screw is on the top. squaring the depth rod is indeed the problem. easier if you use the step measurement as shown in fig d

[HippieDave]

Feeler gauges IMHO are better. What I usually use is a pencil line...just rub a pencil on the bottom of the saddle and gently sand until it uniformaly disappears. then put an old string on and measure your action with feeler gauges.

[ChrisN]

Originally Posted by HippieDave

Feeler gauges IMHO are better. What I usually use is a pencil line...just rub a pencil on the bottom of the saddle and gently sand until it uniformaly disappears. then put an old string on and measure your action with feeler gauges.

Understood and I did use the feeler gauges to determine the string action. My issue was measuring the saddle height before/after taking material off the saddle's top at each string location. I did the job yesterday with the feeler gauges and they worked great.

[ChrisN]

Originally Posted by arie

the left side is where the fixed anvil is, the lock screw is on the top. squaring the depth rod is indeed the problem. easier if you use the step measurement as shown in fig d

Well I'll be (and I hardly ever get to say that). I never heard of a "step measurement" nor I have seen anyone using the caliper in that way. That might have worked for me - it's certainly steadier and more consistent. Thanks for adding to my knowledge storehouse!

[Truckjohn]

Absolutely precision measuring equipment requires a very consistent and steady "touch" in the technique. It's part of the learning curve of using it.

It also requires an extremely consistent placement on the work and attention to orientation.

Reasons you are getting inconsistent measurements:
The saddle is curved end to end
The saddle has little divots in it from the strings
The saddle is curved/shaped front to back
Inconsistent position within the caliper jaws
Inconsistent orientation - the part may be slightly cocked
You aren't measuring in the same place each time
Inconsistent hand pressure - you are flexing the caliper and could even be mushing the part if it's a plastic/synthetic saddle...

Hand pressure wise - the best description I can give you is holding a ripe grape in your fingers so it doesn't slip out. This isn't a bench clamp... It's extremely sensitive precision equipment... You can absolutely flex the unit or the saddle 0.003" or 0.005".

Thanks

[ChrisN]

Originally Posted by Truckjohn

Absolutely precision measuring equipment requires a very consistent and steady "touch" in the technique. It's part of the learning curve of using it.

It also requires an extremely consistent placement on the work and attention to orientation.

Reasons you are getting inconsistent measurements:
The saddle is curved end to end
The saddle has little divots in it from the strings
The saddle is curved/shaped front to back
Inconsistent position within the caliper jaws
Inconsistent orientation - the part may be slightly cocked
You aren't measuring in the same place each time
Inconsistent hand pressure - you are flexing the caliper and could even be mushing the part if it's a plastic/synthetic saddle...

Hand pressure wise - the best description I can give you is holding a ripe grape in your fingers so it doesn't slip out. This isn't a bench clamp... It's extremely sensitive precision equipment... You can absolutely flex the unit or the saddle 0.003" or 0.005".

Thanks

It's like you're watching over my shoulder - all true observations. I'm using the stacked feeler gauges, but they're also sitting on, and measuring, curved surfaces, so it's a challenge to ensure consistent results when determining the stacked gauges exactly match the actual saddle height (to determine current saddle height). I'm measuring all of the string points twice, over 2 days, to make sure I've got the best possible measurement, but I'm sure they'll be different this morning.

I also get inconsistent results when measuring the stack of feeler gauges! Squeeze the gauges near measurement point? One result. Measure squeezed gauges at a slightly different point at the same end of the stack? Different result. Apply varying amounts of thumb pressure to the gauge's thumbwheel when sizing a compressed gauge stack? Yet another result. Frustrating, so I do it enough to get a reasonably consistent consensus number, remembering nothing in life is perfect.

[murrmac123]

I think it is time to point out that neither the Vernier gauge, nor the digital caliper really has any part to play in the process.

You need to step back and think what and how you are measuring.

Assuming that the relief and string height off the soundboard are acceptable (and admittedly, "acceptable" to you might not be "acceptable " to me ...) nevertheless the one primary measurement you require is the action height at the 12th fret. Measured at the e string and also at the E string. And if you are as pernickety as me, at each of the intermediate 4 strings as well.

How do you measure this action ? You can use the StewMac action gauge, which is visually accurate to .015". You can use stacked feeler gauges, which will get you to around .005". By far the best , quickest, and most hassle-free is to use pin gauges, which will give a reading of plus or minus .001"

So you now have six different readings ... you will therefore be able to calculate the six different amounts of material removal you will need in order to achieve the desired action on all strings. I assume I don't need to explain the geometry of that .

So ...knowing the required action height for each string, it is the simplest thing in the world to figure out how much you need to remove from the top of each individual saddle section to achieve the desired end result. This is where your feeler gauges come in. ( Although I prefer using pin gauges here as well).

There is a certain amount of skill required to do that and end up with a visually and functionally acceptable result, but with a bit of practice, it is easily achievable .

[ChrisN]

Originally Posted by murrmac123

I think it is time to point out that neither the Vernier gauge, nor the digital caliper really has any part to play in the process.

You need to step back and think what and how you are measuring.

Assuming that the relief and string height off the soundboard are acceptable (and admittedly, "acceptable" to you might not be "acceptable " to me ...) nevertheless the one primary measurement you require is the action height at the 12th fret. Measured at the e string and also at the E string. And if you are as pernickety as me, at each of the intermediate 4 strings as well.

How do you measure this action ? You can use the StewMac action gauge, which is visually accurate to .015". You can use stacked feeler gauges, which will get you to around .005". By far the best , quickest, and most hassle-free is to use pin gauges, which will give a reading of plus or minus .001"

So you now have six different readings ... you will therefore be able to calculate the six different amounts of material removal you will need in order to achieve the desired action on all strings. I assume I don't need to explain the geometry of that .

So ...knowing the required action height for each string, it is the simplest thing in the world to figure out how much you need to remove from the top of each individual saddle section to achieve the desired end result. This is where your feeler gauges come in. ( Although I prefer using pin gauges here as well).

There is a certain amount of skill required to do that and end up with a visually and functionally acceptable result, but with a bit of practice, it is easily achievable .

Well, while I've got your eye, I've hit some headwinds:

1. Context - I go back/forth between acoustic (fingerstyle/light-touch) and electric, so I like lowish action (.075 or 5/64 on E @ 12th, and I'd prefer .060) E) on my acoustic. I'm working on a 25" scale parlor that appears in good repair. A straightedge on the fretboard *just* kisses the front/top of the bridge. I'm replacing a saddle that was mistmatched on string height and done too low (but guitar never buzzed with light strings - .012s, even with .003 relief) - saddle was a sliver, way below 1/8" in the middle. I want more saddle exposure, stairstepped string height, and low action.

2. History - I've previously done what you outline, albeit relying on feeler gauges at hand. I have my "12th fret action with .003 relief" number for each string. I installed a new saddle (Tusq pre-intonated) at full height (.213 exposed in middle, pre-adjustment), and I have my string-contact points measured on the saddle to obtain current saddle height by string. I've calculated my action differential (current action minus desired action) and multiplied that result by 2 to determine what to remove from the new saddle's top, from which I've calculated the post-adjustment remaining saddle exposure.

3. Problem - At proposed 12th fret action of .75 - .55 (E - e) which is 5/64 (not uncommon or radically low), and relief at .003 (influences action at 12th fret), there's not enough residual saddle exposure (.096 is minimum recommended for Martin and .127 is minimum recommended for Gibson). If I proceed as outlined, I'll have exposed saddle height as follows: E - .122, A - .124, D - .111, G - .109, B - .073, and e - .076.

4. Question - I'm unsure why I can't adjust action to 5/64 on a guitar with a decent neck angle, without running out of exposed saddle. Do you see anything in my approach that might suggest where I'm error?

Any thoughts appreciated.

[charles Tauber]

Originally Posted by ChrisN

Question - I'm unsure why I can't adjust action to 5/64 on a guitar with a decent neck angle, without running out of exposed saddle.

Short answer: you can, but that isn't a decent neck angle.

I haven't double-checked your dimensions, but what it is telling you is the definition of a poor neck angle, or an overly thick bridge, assuming that you have a "suitable" vertical distance from the guitar top to the bottom of the strings at the saddle. (You're missing that important dimension.)