Method and device for tapping an engine component to orient a spark plug

A method of tapping an engine component to orient a spark plug in a combustion chamber of an internal combustion engine, the method comprising:

• mounting a tap to a tool head of a tool;
• measuring a thread pitch of the tap;
• measuring a first distance between an end surface of the tap and a center of a predetermined tooth of the tap, the first distance being measured at a first rotational location of the tap;
• calculating a tap rotation overshoot, the tap rotation overshoot being equal to the first distance divided by the thread pitch of the tap;
• calculating a tap rotational offset, the tap rotational offset being equal to the tap rotation overshoot minus a maximum integer value of the tap rotation overshoot, then multiplied by 360°;
• determining a spark plug offset;
• calculating a tap rotational starting orientation, the tap rotational starting orientation being based on the first rotational location, the tap rotational offset, and the spark plug offset;
• rotating the tool head to the tap rotational starting orientation;
• positioning the tap so that the end surface of the tap is a pitch incremental distance of the tap away from the engine component;
• and
• synchronizing a rotating speed of the tool head and a feed rate of the engine component relative to the tool head to the thread pitch of the tap and operating the tool to cut threads in the engine component.

A threading device comprising:

• a tool including a chuck configured to rotate about an axis;
• a tap coupled to the chuck for common rotation about the axis;
• at least one sensor configured to detect a thread pitch of the tap and a first distance between an end surface of the tap and a center of a predetermined full tooth of the tap, the first distance being measured at a first rotational location of the tap;
• and
• a control module in communication with the at least one sensor and the tool, the control module configured to calculate a location of a phantom first tooth based on the thread pitch of the tap and the first distance, the end surface intersecting the phantom first tooth at a major diameter of the phantom first tooth, the control module being configured to calculate a tap rotational starting orientation based on the first rotational location, the location of the phantom first tooth, and a spark plug offset, the control module in communication with the tool and configured to synchronize a rotating speed of the chuck and a feed rate of the engine component relative to the chuck to the thread pitch of the tap to cut or form threads in the engine component based on the tap rotational starting orientation.