Guide post and master cylinder squareness gage

A guide post or master cylinder squareness gage for measuring the perpendicularity between a cylindrical column and a plane surface, comprising:

• a measurement indicator;
• a vee-block comprising means for magnetically attaching the measurement indicator to the cylindrical column, said vee-block providing at least two transversely spaced positive contacts disposed along the circumferential surface of the cylindrical column;
• a fixed stop mounted to said vee-block for bearing against the plane surface at a first location adjacent to but spaced from said cylindrical column to provide a measurement reference point;
• and
• said measurement indicator including a movable measurement contact biased against said plane surface when mounted to said cylindrical column at a second location spaced from said first location, which movement of the contact relative to the measurement reference point provides a perpendicularity measurement as the measurement indicator is moved in an arc over said plane surface.