Mitutoyo 64AAA218 Thread Pitch Diameter Wire 26 Tpi

Product Description

The MITUTOYO 64AAA218 is a thread pitch diameter measuring wire used to determine the pitch diameter of threaded fasteners and tapped holes with precision. Each set contains 3 wires with a nominal best wire diameter of 0.0222 inches and a nominal constant of 0.032 inches. The wire length is 1.125 inches, and the pitch is 0.04 inches, corresponding to 26 threads per inch (TPI). These measuring wires are used alongside a micrometer to calculate pitch diameter using the three-wire measurement method. Machinists, tool-and-die makers, and quality control technicians rely on these wires for accurate thread inspection and gauging work.

The 64AAA218 measuring wires are suited for inspecting external threads on precision machined parts where pitch diameter verification is required. They are commonly used in machine shops, manufacturing facilities, and metrology labs. At 26 TPI and a 0.04-inch pitch, these wires are sized for the specific thread form where the three-wire method yields the most accurate results when the wire contacts the thread flanks at the pitch cylinder. The set of 3 wires supports the standard three-wire measurement setup used with an outside micrometer.

Key Features

• Designed for 26 TPI threads with a 0.04-inch pitch
• Nominal best wire diameter of 0.0222 inches for accurate pitch cylinder contact
• Nominal constant of 0.032 inches simplifies pitch diameter calculation
• Wire length of 1.125 inches provides adequate handling during measurement
• Includes 3 wires per package to support the three-wire measurement method

Compatibility

Designed for use in the three-wire method of pitch diameter measurement on external threads at 26 TPI with a 0.04-inch pitch. Intended for use with a standard outside micrometer.

Installation Notes

Thread measuring wires are precision instruments and should be handled with care to avoid bending or surface damage that could affect measurement accuracy. Use a micrometer with a suitable anvil face and apply consistent measuring force when taking readings. Store wires in a protective case away from contaminants when not in use. No power tools, electrical shutoff, or fluid isolation is required for this instrument.