This is a post I wrote back in 2007, I cleaned up some of the grammar but otherwise left the technical details alone as I still agree with what I wrote back then.

Compensation is what allows a guitar to play in tune as you move up the fingerboard. When a string is fretted, it stretches slightly. That stretch raises the pitch, and the amount of stretch depends on the action — the height of the string above the fingerboard. Without compensation, every fretted note would play sharp.

To correct this, builders lengthen the scale slightly by moving the saddle back toward the bridge pins. But this isn’t a simple, uniform shift. String diameter plays a major role, and the real variable is the core diameter, not the overall wound diameter. Larger cores stretch more when fretted, so they require more compensation.

Here’s an example of typical core diameters for a set of light strings:

• 6th: .0175″ (core of wound string)
• 5th: .016″ (core of wound string)
• 4th: .015″ (core of wound string)
• 3rd: .013″ (plain steel)
• 2nd: .016″ (plain steel)
• 1st: .012″ (plain steel)

The 6th string, with the largest core, needs the most compensation, so its contact point on the saddle is set furthest back. From there, the required setback decreases until you reach the 2nd (B) string — which, despite being unwound, has a larger core than the 3rd string. That’s why the B string often sits on a small “shelf” cut into the saddle: it needs to be compensated farther back again.

During the build, all of this has to be anticipated so the saddle slot ends up in the right neighborhood. Scale length, action, string gauge, and even alternate tunings all influence where the compensation ultimately lands.

Once the guitar is strung up, I fine‑tune the intonation using a strobe tuner. Small adjustments can be made by moving the saddle’s break point — filing it slightly forward or backward to dial in each string.

If a saddle is tilting forward in the slot (toward the soundboard), that’s usually a sign of a poor fit. I actually mill my saddle slots so the saddle leans slightly back toward the pins, which creates better pressure and stability. The reasoning behind that deserves its own write‑up.

Compensation is always a balancing act. Action, gauge, scale length, and tuning all interact, so there’s no single perfect solution for every scenario. As a builder, I aim for the best middle ground during construction, then refine the saddle for the player’s needs with a strobe tuner.