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Lowenherz or Löwenherz Thread Size Table.

The Lowenherz thread is a largely obsolete fine thread for screws of instruments and is based on the metric system. It is a symmetrical thread, not a buttress thread. The Löwenherz thread has flats at the top and bottom the same as the U.S. standard buttress form, but the angle is 53 degrees 8 minutes.

The depth equals 0.75 × the pitch, and the width of the flats at the top and bottom is equal to 0.125 × the pitch. This screw thread is used for the fine threads of measuring instruments, optical apparatus, etc., especially in Germany.

 Diameter Pitch, Millimeters Approximate Diameter Pitch, Millimeters Approximate No. of Threads per Inch Millimeters Inches No. of Threads per Inch Millimeters Inches 1.0 0.0394 0.25 101.6 9.0 0.3543 1.30 19.5 1.2 0.0472 0.25 101.6 10.0 0.3937 1.40 18.1 1.4 0.0551 0.30 84.7 12.0 0.4724 1.60 15.9 1.7 0.0669 0.35 72.6 14.0 0.5512 1.80 14.1 2.0 0.0787 0.40 63.5 16.0 0.6299 2.00 12.7 2.3 0.0905 0.40 63.5 18.0 0.7087 2.20 11.5 2.6 0.1024 0.45 56.4 20.0 0.7874 2.40 10.6 3.0 0.1181 0.50 50.8 22.0 0.8661 2.80 9.1 3.5 0.1378 0.60 42.3 24.0 0.9450 2.80 9.1 4.0 0.1575 0.70 36.3 26.0 1.0236 3.20 7.9 4.5 0.1772 0.75 33.9 28.0 1.1024 3.20 7.9 5.0 0.1968 0.80 31.7 30.0 1.1811 3.60 7.1 5.5 0.2165 0.90 28.2 32.0 1.2599 3.60 7.1 6.0 0.2362 1.00 25.4 36.0 1.4173 4.00 6.4 7.0 0.2756 1.10 23.1 40.0 1.5748 4.40 5.7 8.0 0.3150 1.20 21.1 … … … …

Measuring Lowenherz thread pitch formula with three wire method:

When measurement M is known:

E = M + P - 3.2359 W

When pitch diameter E is used in formula:

M = E - P + 3.2359 W

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