Datuming device for measuring displacements not parallel with a displacement probe's line of travel

A datuming system for use with a machine tool having a movable member comprising;

• a datuming device situated on said movable member;
• a displacement probe for probing said datuming device to measure displacement;
• a non-sensitive surface, said non-sensitive surface acting as a reference for said probe, and
• a sensitive surface, situated on said datuming device, which when probed by said probe exhibits a changing displacement when said movable member is moved from a first position to a second position.

A datuming system, comprising:

• a datuming device situated at a fixed location;
• a displacement probe for probing said datuming device to measure displacement with respect to said datuming device;
• a non-sensitive surface, said non-sensitive surface acting as a reference for said probe, and
• a sensitive surface, situated on said datuming device, which when probed by said probe exhibits a changing displacement when said probe is moved from a first position to a second position.

In a machine tool having a movable member which is probed by a displacement probe, a method of measuring displacement comprising the steps of:

• providing said member with a datuming device including a non-sensitive surface and a sensitive surface;
• probing said non-sensitive surface and said sensitive surface to measure the drop therebetween when said member is in a first position;
• moving said member to a second position, and
• probing said non-sensitive surface and said sensitive surface to measure the drop therebetween when said member is in said second position,