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I've done a search but didn't come up with much, perhaps some of you folks could provide some thoughts. I was looking for the advantages or disadvantage to the spacing of the bridge pin holes from the saddle. Is there an optimum distance that you look for the bridge pin hole to be behind the saddle? I was thinking about laying out the holes in a radius to match the bottom side of the bridge. Is there a disadvantage to this? I know the advantage in this being that the holes don't fall within the same grain lines of the bridge and less likely to cause splitting. Thanks for any input.

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Kyle

Yes, sorry for being unclear. Where the pins are in a semi circular pattern as opposed to being inline.

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Kyle

Kyle, there is a very interesting article by Frank Ford on his site called "Frets" on bridge pin placement in relationship to the saddle. It has great pictures as well. You might find it helpful. Look for the one titled, "Looking at saddles."

Also, Kent Everett insists that bridge pins should be in a straight line so that the bridge can rock when it vibrates. That being said, I have heard others say that the bridge does not rock in this manner when producing sound.

The bridge does rock and that produces some sound, but not as much as some folks think. At any rate, it's more a function of how high the strings are off the top, and the location of the bridge pins has little, if any, effect.

When I spoke with Frank some years ago he said that it's harder to sell guitars with the pins in an arc. Partly it's due to concerns about break angle, and partly it's because Martin doesn't do it that way. I think break angle concerns are exaggerated, and you can sometimes convince people but it's hard to counter the 'Martin-didn't' objection rationally.

At that time I was putting the pins in an arc, mostly to ensure that they didn't all fall on the same grain line, and cause a split. After that I switched to making them in a straight line, but following the saddle angle, rather than perpendicular to the center line of the guitar (which is how Martin does it). The angled line lessens the chance that you'll get the double winding of the low E string up on the saddle (which happens on old Martins) and gets the pins off the same grain line (unless you mess up choosing the wood, and that's your fault). I put the centers of the holes 11-12 mm behind the saddle.

I haven't built in enough ways to know if the distance makes a difference but the research I've done has concluded that it does not. As Lon as you have enough break angle that the strings are putting pressure on the saddle then that's all that matters. At least that seems to be the consensus from my research.

My bridge pins are in line with the slant of the saddle and spaced 1 cm (.39") from the centre of the saddle slot (⅛" saddle). I have seen some guitars in my shop for repair that have had the curved pin layout and break angle can be a problem if the guitar has a low saddle. I understand that some people like the look of the curved layout, but it has always made sense to me to keep a consistent spacing that is reasonably close to the saddle. Than you know break angle will never be an issue.

Josh

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Josh House

Canadian Luthier Supply
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House Guitars - Custom Built Acoustic Instruments.
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Thanks for all of the input. Seems the angled layout is the preferred method. Josh has a great point about break angle on lower saddles. Thanks again.

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Kyle

As Josh says, it doesn't take much break angle on an acoustic to keep things working right. Break angle does make a difference with USTs though, which tend to like all the down pressure they can get. THe curved setup might be an issue there, unless you ramp the middle strings. The angled line just simplifies it no end.

BTW, USTs also like a back angled saddle. In theory, you get the max down pressure when the saddle bisects the break angle. This also eliminates the tipping force on the saddle that tends to break out the front edge of the bridge, and that's enough reason for me to use it.

Since the saddle is not a constant height above the bridge, a straight line does not give a constant break angle. I use a slight curve, with the treble side a bit closer to the saddle than the bass side. This keeps the break angle of each string close to the same(which is of little importance), and also keeps the pins off the same grain line. An added advantage(for those of us that do less than perfect work) is that slight mistakes in pin location are less visable.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Actually the pin layout , (and Alan and I have discussed this in detail a while ago on break angle ), when using the Martin model the higher end guitars use a pin line parallel to the front of the bridge
the lower end guitars travel with the saddle. I doubt that one is better than another. Pick your poison. Henderson does radius his pins.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

And there you have it!

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Pat

If the experiments I've done on a Classical are any indication of what matters on a steel string, the break angle has no particular effect on the acoustic sound, so long as it's 'enough'. You'll probably know if it's not! Break angle matters for USTs, as I said.

If you make the bridge thicker on the bass end (like Martin), it can facilitate a uniform saddle height. IMHO, part of the characteristic sound (or feel) of a Martin is due to the greater break angle on the bass strings. Collings uses a parallel saddle design.
When Martin introduced their low end 'New Technology' models around 1993, they featured a different bridge design. The pin holes are much lower, and are parallel to the slanted saddle. This increased distance to the saddle is coupled with string ramps to increase the break angle. It is a functional design, but IMHO it is ugly.

As far as bridge rocking is concerned, I see no difference when the pins are in an arc. Rocking is driven by the torque on the bridge, which is a function of the height of the strings above the top.

You can also angle the grain in the bridge, by starting with a wide blank. When working with a blank that has angled grain, I usually slant it opposite the saddle angle, just to help strengthen the saddle slot against splitting. Most of the bridges I make have a long through slot, and I like to angle the slot back about 3 degrees.....except on collector grade guitars.

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John

I just do what works for me.
YMMV.
It is entirely possible to build a bridge that will never split through the bridge pin holes. But whether anyone will buy it is another matter.
As a repairman, replacing or repairing a split bridge is very common, and is not the end of the world. It is much more of an issue for a beginning luthier with little or no repair experience.

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John