My Stihl USG grinder chart 2025. Offset grinding explained

The USG grinder is a very old design around the 1960s and was made with an offset of 17mm from the C scale pivot point to the tip of the cutter. Because of this, the grinder will always have offset from the C scale pivot point. This offset means the center line of the grinding wheel is not grinding in the center of the wheel.

Many chains do not require offset grinding, only full chisel. The USG chart keeps changing and has never been 100% accurate, with modern chains being offset for full chisel.

There is no mention of 10° downward tilt, although 10° tilt is built into RS chain at manufacturer. Oregon chainsaw grinders are much more upto date in this area.

while the USG grinder is a well-built, quality machine second to none.
The USG chart keeps changing, but the settings are not correct for all chains. There are many mistakes in this chart and no printed information about the settings. They assume you have good knowledge and don't require additional information in the form of explanations regarding setting parameters.

My settings are more in line with modern settings, including 0° at the pivot point. This is a neutral setting for semi chisel and Hexa profiles where the grinding takes place at the grinding wheel centre line.

For full chisel 10° tilt settings are shown below in my 2025 USG chart settings

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Tinker O’Toole USG Chart 2025

0° Neutral position on grinding wheel ( no Tilt )
Set B scale
+10° Right hand cutter
-10° Left Hand cutter

Full chisel chain with 10° Tilt offset grinding.
Set B scale to 0° for left and right cutters

Hexa no tilt set B scale to neutral position.
+10° right hand cutter
-10° left hand cutter
Set A scale 30° Set C scale 25°

Generic Settings
Top Plate cutting angle A scale 30° to 40° ( Stihl USG Setting )
Top plate angle 25° to 30° ( Stihl USG Setting )

The neutral grinding position is when the bottom of the grinding wheel comes in vertical alignment with the cutter point approximately.

Offset grinding is where you grind away from the centre line ( example 10°downward tilt will grind approx 10mm away from the centre line.

Revision v1 Feb 2025