Saddle slot compensation angle question

[jantric]

My question is, is the angle the for all scale lengths the same on steel string guitars? I have basically copied the bridge from my martin kit to make more bridges the only thing I did different was the size of slot I cut it 1/8'' rather than the 3/32'' of the original. At this point I see the opportunity play with the bridge shape some what and use some woods I have on hand. I finally got the chance to work on the jig to day. I cut three different test pcs. will post some pics of the final results soon. Yahoo.. thanks Rick

[B. Howard]

The angle will vary a bit with scale length if one wishes to be precise, but it's really minimal. A 1" change in scale only changes the difference in the relationship of length of the e strings by about 0.005". String spacing at the saddle will have a similar effect, but again not really enough to worry about.

[tippie53]

I found a 3 degree angle seems to help with the intonation the best. Using a .125 saddle will afford you the best chance of intonation but you will never get all frets to be dead on. Intonation is a skill that you will be needing to understand.
The variables are
1 action height , the higher it gets the more sharp you will pull intonation sharp
2 Play technique
3 fret height
4 gauge of strings.
5 working length of the string

Non variables
scale length
compensation angle
compensation length

you need to match these the best you can. As you do more of this work you will soon see the relationship. I can say that the major change once the guitar is set up and you change gauges of strings you may need to adjust relief and the intonation may change.
Even once you set up the guitar and have good intonation as the string changes from work hardening you may notice that B and G want to wander and not stay in tune

NOTE
also one thing that can play havoc with intonation may be the nut and saddle radius. Steel won't bent at a given point. I tend to radius the bottom of the nut slot from the zero fret position to the headstock. Think Roller. You may notice that a string sound dead in the open position but is clear fretted, that is a clue that the nut is the issue.

[Dan Bombliss]

When I do intonated saddles on an acoustic, I use the "cut off" scrap of a G String from an acoustic guitar, because the G strings core is the thinnest gauge. Usually the very end of the string (that you cut off) has a short bit of the core exposed, with out any wraps, and what is the part I use for this. When the guitars strung up, you can detune it a little, and put the thing piece of string underneath the string, on top of the saddle. What the enables you to do is move the peak (the thin string) back and fourth on the saddle, changing the place to actually find and mark where the peak would need to be.

The reason why I explained that is because you're question lead me to something I've never tried, but seems quite plausible. What I would do in you're position, if you're looking to physically try an angle and see what works for what you have, this might work. Granted, you would have to have a saddle routing setup similar to stewmacs, where you route the saddle after the bridge is glued on. So with that said, you can string up this guitar, and no slot is slotted yet.

I'm picturing in my head this working just fine, but who knows. You could potentially take a thin piece of solid wood, or you pick the material. A piece of solid wood that would be as thick as the amount of saddle would stick up above the bridge. Say this piece of wood is 1/2"x4". You lay it on top of the bridge (That has no saddle routed yet), and you could do the same trick. You could string it up with this piece there, and you could put the core of the G string under, and move that "peak" around to find where you're intonation would be, and mark it. When you go through the strings, it would display to you what you're range is. Then you're decision would be, how thick does this saddle have to be to accommodate this guitar/strings, and at what angle.

May be more effort than it's worth, because there are some "general" angles to figure, but that would physically display the science and reasoning, oppose to asking someone else to answer it for you (which isn't always correct. As alot of things are subjective for predetermining just about anything). For a martin style, and for the light gauge strings I use, I've been using a .125" saddle width, and my angle is determined by this: Scale length + 1/32" at the high e, and scale length + 5/32" at the low E.

String spacing would affect what that angle actually comes out to, as far as specific degrees. So assuming you'd might change you're spacing at any point in time, it's universal.

-Dan

[jantric]

Wow thanks so much every one for your sharing of your experience or experiences. I have read each of them several times and I'm totally blown away by the context of them. I can clearly connect with what each of you are saying. I am very excited about moving on to the next step ....sand the bottom of the bridge to match curve of the top etc. the idea of intonation while it is temporally attached is genus ... thanks Rick

Rick,
Do you have a CNC setup or are you making your bridges by hand?

-tommy

[jantric]

No I followed Johns tutorial method.I used three practice pcs. before I got it down. so I' making by hand..Rick

[tippie53]

glad you found that tutorial useful