Crash course in intonation

[Jmorris]

Throughout many threads, intonation is brought up time and time again. I've read on several threads that the builder didn't drill his bridge holes until after he had found (or marked or located) the correct intonation. As I have not yet drilled the location of my bridge yet, this has me baffled and cautious. Can someone give me a quick rundown of why this is done? Kinda like a "intonation for dummies" type thing? I'm currently using the Bartlett plans and I'm curious if I just go straight off the plans with my bridge location am I gonna have problems?

[Bgetraer]

I am not by any means qualified to fully answer your question, but i will try to anyway just in the spirit of trying to be helpful. I would wait for further advice before acting however.
that said, intonating your guitar ideally allows the frets to play in tune, playing each note perfectly, all the way up the neck. with the frets going straight accross for every string however, this is not really possible, so the goal becomes to get it as close as possible. what the placement of the bridge does, is it locates the bridge in relation to the 12th fret so that it plays the exact same note as the harmonic at the 12th fret.
The scale length of the guitar is generally determined by the distance of your nut to the middle of the bridge. however, i think that this measurement is more of a starting point in terms of intonation. it more determines the layout of the frets than the position of the bridge, which is determined by finding the spot where the 12th fret plays the same note as the 12th fret harmonic.

when using a tunematic, each strings length can be adjusted individually, but only slightly. therefore, when placing the bridge, the goal is to get the outside strings (the two "E" strings) intonated as closely as possible when the bridge is first positioned, and the rest of the strings will thereby be within the range of the movable saddles that allow the intonation on each string to be set even more precisely.
the way to accomplish this first goal of lining up the outside of the bridge (the two e strings) to achieve proper intonation is to slant it in order that both string are intonated correctly. it is therefore slanted downward towards the low e side. this slant varies from guitar to guitar, as the correct spot of ideal intonation is different on each guitar. while your plans are very accurate and should provide the best starting point, following them blindly could easily lead to problems if one of the saddles cannot be moved far enough forward or backwards. additionally, it is probably a VERY good idea to fully grasp what is going on (which at this point i certainly hope I do ) because it will give you a better understanding of the overall functioning of your guitar.
what many do to properly set the intonation of their guitars is to make a properly sized wooden shim in order to string up their guitar and intonate the outside strings before drilling for the posts. this allows them to angle, move and otherwise adjust the position of the bridge before marking the spot for the posts and drilling. this shim can be seen in Expo's build thread:


it is also described in greater detail in several other builds which you can find on this forum.
i hope this helps to answer your question, and give you a better understanding of the hows and whys, but please wait for someone else to weigh in on this as i am not very experienced at all and this could mean the difference between an awesome guitar and just an awesome looking guitar...
from one learner to another, good luck
benjy getraer

[Barnaby]

You might well have issues if tolerances are not exact (and they almost never are when working with wood). The problem is that a small difference in one part of the guitar can mean a big one somewhere else. If you shave off the sides of your tenon slightly for a better fit, for example, the whole neck will be differently positioned, which will mean that your scale length would be shorter and your frets would be out of tune. Therefore, the bridge should be slightly further back. Of course you can compensate by moving saddles, but only so much, and different strings need different saddle compensation too. You want the best possible placement to maximise the chances of good intonation. I think it is always best to find an ideal spot once the neck, fingerboard and tailpiece are all there. Simply locate your bridge relative to those. There are lots of threads on here which give precise measurements for doing so, as well as instructions for tuning calculations.

If I remember correctly, the Bartlett plans actually say this too.

I have played quite a few guitars which are out of tune because they were put together in a factory and the bridges were not individually located. On the plus side, this is one of the advantages of a luthier-made instrument. They're much more in tune because these small details are gotten right.

EDIT: While I was writing, another, clearer post appeared. Nice one, Benjy!

[Bgetraer]

Thanks! Feels nice to help out for a change instead of being helped out.
Benjy Getraer

[alk-3]

Bgetraer is absolutely right. Don't blindly follow where the plans say to drill. You also want to move the bridge side to side for proper alignment of the strings with the neck, and once you have it set where you want it you can go ahead and drill and install the bridge. At this point you will want to install your pickups and pick guard so that the pole pieces line up under the strings, the pick guard has the righ gaps etc..

[Fred_Garvin]

I'm not qualified to comment either, but go with what Bgetraer said.

[Jmorris]

Thanks all. That was a huge help.

['59_Standard]

Check Sully's video: Here

[Reverend D]

As mentioned you want to get this measurement as close as possible. You do have a little bit of fudge factor in the adjustment of the bridge (what say a 1/8-1/4" depending on the bridge).

Most people try to get that measurement in the middle of the bridges adjustment area. If you get it in that area you can then adjust up or down to achieve the best compromise of being in tune. I say compromise because it truly is, its never perfect but you want it as good as you can make it obviously.

That's why most people don't like kits that have the bridge pre-positioned in a spot, it just is almost always not in the right place either up or down and back or forth. Good luck on your project!

Regards,

Don

[gator payne]

I think anyone building their first guitar, be it acoustic or electric should study the hows and whys of intonation, the difference between true temperment and equal temperment and why equal temperment is the most common practice for guitars.

With this in mind mike Dooling, a renowen luthier wrote a series articals to help new builders understand the history and theroy of intonation. My personal opinion this is one of the best short but insightfull to intonation tutorials out there. Heres is the link.

Ask the Luthier

Be sure to read all the articles not just the opening.

[Jmorris]

I've owned dozens of guitars and played hundreds more. Intonation is something that has never crossed my mind. If I had issues I'd just bring it somewhere and have it set up. This is all so Greek to me. And i haven't had much luck finding information online in a manner that I could easily understand. This forum has been a huge help.

[gator payne]

Originally Posted by Jmorris

I've owned dozens of guitars and played hundreds more. Intonation is something that has never crossed my mind. If I had issues I'd just bring it somewhere and have it set up. This is all so Greek to me. And i haven't had much luck finding information online in a manner that I could easily understand. This forum has been a huge help.

Read the post just above yours. Follow the link to the information you quest!!!

[Jmorris]

Thanks gator. We must have made or post at the same time. Thanks again.

[Ole'Lefty]

One thing to watch out for is that some of the "nut to 12>12 to bridge" calculations are frequently at minimum. I discovered this the hard way with TOM intonation for 24.625 in the StewMAc "Frets calculation" when they give + or - .030--well, I warn everyone to "go long" on that. I mark for that maximum-then on the ones I have set by tailpiece and shimmed bridge they invariably ("reality") line up with the more generous end of the numbers. One of the few StewMAc bits of not quite enough information.

Here is how fussy it can be. I did a nice Eden bare guitar. It was getting a bigsby. I used a mathematical for the bridge placement-for a roller bridge. Would not intonate-dropped a Nashville on it and even with the more generous range it has, the bass"E" was sharp. Removed saddle, turned it around for more space and finally got it right. As you can see, I used up every realistic approach to getting it right. USE CAUTION with any math based intonation recommendation. Better to use the mock-up.

[Barnaby]

Originally Posted by Ole'Lefty

One thing to watch out for is that some of the "nut to 12>12 to bridge" calculations are frequently at minimum. I discovered this the hard way with TOM intonation for 24.625 in the StewMAc "Frets calculation" when they give + or - .030--well, I warn everyone to "go long" on that. I mark for that maximum-then on the ones I have set by tailpiece and shimmed bridge they invariably ("reality") line up with the more generous end of the numbers. One of the few StewMAc bits of not quite enough information.

Here is how fussy it can be. I did a nice Eden bare guitar. It was getting a bigsby. I used a mathematical for the bridge placement-for a roller bridge. Would not intonate-dropped a Nashville on it and even with the more generous range it has, the bass"E" was sharp. Removed saddle, turned it around for more space and finally got it right. As you can see, I used up every realistic approach to getting it right. USE CAUTION with any math based intonation recommendation. Better to use the mock-up.

This is great advice. I'm really not that bad at mathematics at all, but frequently find that the sheer number of variables involved make calculations irrelevant when it comes to fine details in building. Bridge placement is much more than mere theoretical scale length.

One other thing is that, when you do manage to get a guitar properly intonated (not perfectly so...that's a whole different story), it 'sings' in a way that makes it come alive. The feeling of playing one is noticeably different.

[Jmorris]

I've tried my best to read the link that gator posted above. Holy moly that is some serious stuff. Found a local repair guy I'm gonna call up and see if maybe he can show me "hands on" how to do this stuff. I'm much better at doing something if I can see how it's done. And this is something I really need to know. Thanks for all the info and advice.

[Time-bandit]

Yea it is a bit more than just how too locate a bridge. With that said it does explain the theory rather simple and in simple phrases. Knowing Gator I suspect he was trying to give you the chance to educate your self to actuall understand intonation rather than just take a shot in the dark at locating the bridge. I know most of the time Gator tends to not only tell you how to but also tends to help you understand why you do it the way you do in the first place. After all that is just the first step in the process to setting intonation.

Really it is not a had read at all and is pretty clear simplified synopsis of what can be much more complicated subject.

[Tim91]

I had a similar question a while back and got alot of good answers and pictures.

Need Help/Drilling Holes for the Bridge

[Jmorris]

Originally Posted by Time-bandit

Yea it is a bit more than just how too locate a bridge. With that said it does explain the theory rather simple and in simple phrases. Knowing Gator I suspect he was trying to give you the chance to educate your self to actuall understand intonation rather than just take a shot in the dark at locating the bridge. I know most of the time Gator tends to not only tell you how to but also tends to help you understand why you do it the way you do in the first place. After all that is just the first step in the process to setting intonation.

Really it is not a had read at all and is pretty clear simplified synopsis of what can be much more complicated subject.

Well damn, now I really feel dumb as a rock lol. I didn't find it so easy to understand. But then again, me + reading material + retaining and understanding what I've read, has never been my strength. But I shall press on. Glad I asked the question in the first place though. I was a heartbeat away from drilling the post holes based right off the plans. Glad I didn't.

[Ole'Lefty]

J: glad you dodged that bullet. The nice thread a couple of messages up is a good and direct take on it.If you can reasonably get to a drill press, do so. I have tempory use but real tailpieces I mail out to loan to people who just can't find one-let me know.

[Jmorris]

Originally Posted by Ole'Lefty

J: glad you dodged that bullet. The nice thread a couple of messages up is a good and direct take on it.If you can reasonably get to a drill press, do so. I have tempory use but real tailpieces I mail out to loan to people who just can't find one-let me know.

Thanks. I had a chance to speak with a tech at a small local music store. He basically told me to do everything that's mentioned here and then bring my guitar to his shop and he will show me how to set the bridge and intonation. Lol he stressed "show" me, he's not going to do it but rather guide me through doing it myself. And no charge!! Cool guy huh?