Bridge Saddle Angle

[buffalohunt]

Hi. I am looking at placing the bridge on my first acoustic build.

I've already made the bridge with the holes drilled and the slot for the saddle routed out.

I copied the saddle angle from a cheap pre-made bridge that I bought off eBay. After further research though, I think my saddle angle is a little too steep. The difference between the high-e string to the low-e string is just under 1/4" instead of the ~1/8" difference that I am seeing on most resources.

It is making it difficult to place the bridge at an appropriate spot for me to get enough room for perfect intonation on both sides of the saddle. Should I just split the difference and get it as close as possible?

[Bruce Sexauer]

Being in tune is crucial, the closer the better. You could save your bridge by increasing the divergence from perpendicular to the center line of the guitar . . . but don't. Fill the slot accurately with the shame kind (scrap from the actual bridge) of wood, glue the bridge on, and then machine the new slot where it actually goes.

On my guitars, I put the leading edge of the e side of the saddle at exactly double the nut to 12 fret and compensate the saddle .030 on the e, and .065 on the b. I put the leading edge of the saddle 11/64" back from double the nut to 12th on the E, then compensate the E .085, the G not at all, and the A and D in a straight line between them.

This works well for Martin standard action with minimal relief: 2/32 x 3/32 at the 12th. The nut MUST be perfectly adjusted. For "Bluegrass" action, add between 1/64 and 1/32 to the saddle location, depending on how hard core the player is.

If this doesn't make sense, consider hiring a pro for this crucial process.

[buffalohunt]

After checking my 3 other acoustics, it seems that I'm not far off.

The angle pretty well matches my 1959 Gibson LG0 and Yamaha guitars. My Sigma 00 is closer to the "standard" 1/8" difference between the high and low E strings.

[evtkw]

Bruce, thank you for sharing your compensation method! I was wondering if you would be willing to clarify a few things for me.

Is the b string .065" from the front of the angled saddle (not from scale length)?

Is the g string right on the front of the saddle based on the same angle?

I calculate a saddle angle of 4.37 degrees for a 2.25" string spacing. Does that seem right?

Your high e string string compensation is much less than most I've seen at .030 and your high E string is more than most at .085+11/64=.257". Do I have the numbers right?

Could you elaborate on how you created your method of compensation?

I am making the bridge for a guitar intended for low tunings, and am thinking it would be a good idea to compensate the saddle appropriately. I have the guild of american luthiers spreadsheet made by Sjaak Elmendorp but have not been able to verify if it is being used successfully by builders.

Thank you again for sharing your knowledge!

[Fathand]

One fairly accurate way to determine the best bridge position with a premade bridge is to attach a trapeze or dobro style tail piece to your guitar. String it up and move your bridge around like a floating bridge until you determine the best place. You can get away with just the 2 E strings or You can even determine if compensating the bridge will help with all strings on. There is a Stew Mac video on this.

Once in position I drill 3/16" through the 2 E string holes so the bridge can be put back correctly later with 3/16" bolts through the clamping caul. I will have masking tape on the top which I can cut around the bridge and leave on the top to mask the bridge location from your finish.

[evtkw]

Thanks for the tip! It is a great idea. I'm building from scratch, and should cut the slot after installing the bridge, but I'm not super confident in my ability to do it. So I'm trying to figure out a good start that leaves me enough room to adjust the saddle after. If I can get it close enough I can use your system, which makes a lot of sense. Any tips on calculating the starting point so I don't have to have a slanted bridge if my slot doesn't allow for enough compensation with my slacked strings?

[Fathand]

Originally Posted by evtkw

Any tips on calculating the starting point so I don't have to have a slanted bridge if my slot doesn't allow for enough compensation with my slacked strings?

I cut my saddle slot before installing bridge so I can use the floating bridge method. I use a milling machine because I have one. It is close enough for me. At the point where the first string meets the saddle, I cut for 1/16th inch longer than scale length. At the 6th string I go 1/8 inch longer. That is for 24.75 or 24.9" scale. If you use the Stew Mac fret calculator it can provide you with suggested compensation for your scale length. You can always add some compensation to the saddle.
https://www.stewmac.com/fret-calculator/

Loose string tunings may affect compensation length but if you select string gauges you can use tauter strings. If using the floating bridge method I would tune the strings to the tuning and gauges you use most often.

[RogerHaggstrom]

Originally Posted by Fathand

One fairly accurate way to determine the best bridge position with a premade bridge is to attach a trapeze or dobro style tail piece to your guitar. String it up and move your bridge around like a floating bridge until you determine the best place...

This is what I did before I realized that the intonation slant of the saddle is not the same with a tail piece and a pin bridge. With a pin bridge you need to have a bigger angle on the saddle and a longer open string length on the thick E string. Only the intonation positions of the unwound strings will be correct with both methods

The reason for this is that the windings on the wound strings will pack together under the string with the steeper breaking angle over the saddle on a pin bridge compared to a tailpiece. This adds to the length of the string close to the saddle that actually don't vibrate.

If you have a premade loose bridge to glue with a slanted saddle on it, the tailpiece method will work nicely if you adjust the position with a tailpiece and only use the thin e-string for checking the intonation position. If the bridge is glued straight, the standard slant of the saddle on the premade bridge will work for the unwound strings. Make sure you have the right string height and string set thickness at the 12th fret when measuring.

[evtkw]

Thank you for the information, that makes sense. I'm still struggling with with how builders estimate the compensation before hand if it is a non standard design or tuning.

If a Martin 25.34 scale length and standard tuning is used, then the martin 2.6 degree saddle angle can be used with their high e setback and a compensated saddle.

But what about if the player mostly uses open F tuning (C2 F2 C3 F3 A3 C4) or other significantly lower tension tunings?

Similarly, builders make multi-scale necks with non standard scale lengths - how are they dealing with the compensation on those guitars?

[Fathand]

Originally Posted by RogerHaggstrom

This is what I did before I realized that the intonation slant of the saddle is not the same with a tail piece and a pin bridge.

This is interesting, I can only say that it worked for me and my ear. I adjusted the bridge with both E strings until I was satisfied.

[Taylor Ham]

Originally Posted by evtkw

Thank you for the information, that makes sense. I'm still struggling with with how builders estimate the compensation before hand if it is a non standard design or tuning.



If a Martin 25.34 scale length and standard tuning is used, then the martin 2.6 degree saddle angle can be used with their high e setback and a compensated saddle.



But what about if the player mostly uses open F tuning (C2 F2 C3 F3 A3 C4) or other significantly lower tension tunings?



Similarly, builders make multi-scale necks with non standard scale lengths - how are they dealing with the compensation on those guitars?

Plot the compensation for each string, and taking into account the width of the saddle, find a location and angle that accomodates those points. When using a wound third, the G may ends up off the front of the saddle, but a little more compensation doesnt hurt. Alternatively, some builders like Takamine and Lowden have used a split saddle to better accomodate this. Others like Somogyi have tended towards a wider saddle, about twice as wide as usual. There are various calculators online to help with this, the easiest and most thorough being R.M. Mottola's.

[RogerHaggstrom]

Originally Posted by evtkw

Thank you for the information, that makes sense. I'm still struggling with with how builders estimate the compensation before hand if it is a non standard design or tuning.

If a Martin 25.34 scale length and standard tuning is used, then the martin 2.6 degree saddle angle can be used with their high e setback and a compensated saddle.

But what about if the player mostly uses open F tuning (C2 F2 C3 F3 A3 C4) or other significantly lower tension tunings?

Similarly, builders make multi-scale necks with non standard scale lengths - how are they dealing with the compensation on those guitars?

When I "build" (I actually restore guitars) I measure the intonation before placing the saddle on the glued down bridge.

Different scale lengths will change the intonation slant on the saddle, and so will a multiscale neck. Actually, every guitar will need special intonation of both the nut and saddle if you want the best intonation possible! The "standard slant" of the saddle is just something that works OK on any guitar with standard tuning, strings and open string length.

Intonation is VERY dependent on the tuning of the strings. That and the string height at the 1st and 12th frets and also (to a less degree) the thickness of the strings. The new fad (to me!) to use alternative tunings on the same guitar is a catastrophe for the intonation, each tuning should have a different setup on both the nut and saddle if intonation is important.

[evtkw]

Taylor: Thanks for the response! I have played with the calculator you mentioned; have you used it successfully? It doesn't seem to agree with my martin specs, so I wasn't sure about it or how much it had been used in real applications.

Roger: Thanks, your system makes sense - but how do you calculate the saddle angle? Or do you measure all the strings, then cut the saddle? Also, how do you measure the needed compensation before putting the saddle on if you don't use the tailpiece method?

[RogerHaggstrom]

Originally Posted by evtkw

... Roger: Thanks, your system makes sense - but how do you calculate the saddle angle? Or do you measure all the strings, then cut the saddle? Also, how do you measure the needed compensation before putting the saddle on if you don't use the tailpiece method?

Good questions! Well, it's a long story, too long to write in a forum post. I have just written an article about it with a lot of pictures that will be published in the membership paper for the Guild of American Luthiers, the American Luthierie. I'm Swedish, but I'm allowed to write anyway. It will be out in December I'm told, you can read all about it there :-)

A short version is that I measure the intonation points in both the nut and saddle, then cut the saddle in the bridge to match the measured intonation points. To do that, I have made a little adjustable gizmo using a brass string pin to be able to find the intonation points at the saddle, and loose bits of tangless frets to find the intonation points at the nut.

[rick-slo]

Inharmonicity of steel strings is why saddles need to be angled. The amount of that is dependent on scale length, string tension (consider different tunings and strings material and gauges). There are formulas for that but as some elements vary with a given guitar built guitar you need to ballpark it to some degree.