Special Thread Measuring Wires (+/- .000020") - Metric

Thread Check Inc. offers special sized thread measuring wires that meet or exceed national standard ANSI/ASME B1.2, ANSI/ASME B1.16M, and ASME B89.1.17-2001. The 3 wire method is the most accurate and universally method of measuring the effective or pitch diameter of an external screw thread.

SKU Description TPI Each
STMW-.1016-.1270-MP Special Thread Measuring Wires (+/- .000020") - .1016mm-.1270mm TPI .1016mm-.1270mm
STMW-.1270-.1778-MP Special Thread Measuring Wires (+/- .000020") - .1270mm-.1778mm TPI .1270mm-.1778mm
STMW-.1778-.2540-MP Special Thread Measuring Wires (+/- .000020") - .1778mm-.2540mm TPI .1778mm-.2540mm
STMW-.2540-3.429-MP Special Thread Measuring Wires (+/- .000020") - .2540mm-3.429mm TPI .2540mm-3.429mm
STMW-3.429-6.604-MP Special Thread Measuring Wires (+/- .000020") - 3.429mm-6.604mm TPI 3.429mm-6.604mm
STMW-6.604-9.779-MP Special Thread Measuring Wires (+/- .000020") - 6.604mm-9.779mm TPI 6.604mm-9.779mm
STMW-9.779-12.954-MP Special Thread Measuring Wires (+/- .000020") - 9.779mm-12.954mm TPI 9.779mm-12.954mm
STMW-12.954-16.129-MP Special Thread Measuring Wires (+/- .000020") - 12.954mm-16.129mm TPI 12.954mm-16.129mm
STMW-16.129-19.304-MP Special Thread Measuring Wires (+/- .000020") - 16.129mm-19.304mm TPI 16.129mm-19.304mm
STMW-19.304-25.654-MP Special Thread Measuring Wires (+/- .000020") - 19.304mm-25.654mm TPI 19.304mm-25.654mm
Set Descending Direction
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Additional Info

Certified Thread Measuring Wires

P.D. = Pitch Diameter
M = Measurement over wires
W = Wire diameter
C = Constant
C = .86603 x Pitch (inches) -3W
P.D. = M-C
W = .57735 x

Thread Measuring Wires

Tolerance and specifications:

  • within .000020" of best wire diameter for specified tpi.
  • within .000005" of the calibrated size provided on label.
  • have the same diameter within .000010".
  • roundness within .000010".
  • taper does not exceed .000010".
  • standard 2" lengths.
  • minimum hardness of RC 62.5.
  • surface finish lapped, 1 MU AA.
  • traceable to NIST.
  • wires meet or exceed Federal specifications ASME/ANSI B1.2 and B1.6M for Grade A Master Thread Wires

Use of best size wires

In measuring screw threads it is desirable to use wires which touch the thread at or near the pitch diameter for the reason that with such "Best Size" wires the measurement of pitch diameter is least effected by an error in the included angle of thread.

Certified Thread Measuring Wires

Notes: Maximum and minimum wires should be used which are safely within the limiting dimensions given by the above formulas.

Call for information and pricing of special wire diameters including Whitworth, British Association, Buttress and worm threads.

Root Diameter Wires:
60° and 55° threads from 41/2-64 TPI.
Price per set of 3 wires.
Call for prices.

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