Locknuts

Brass Locknuts are the recommended items used in securing brass cable glands, unions, adaptors, reducers, and stopper plugs to a gland plate or into equipment.

Zinc Plated Mild Steel locknuts are a cost effective alternative to brass locknuts and should only be used in dry, low humidity conditions.

Aluminium locknuts are recommended when installing CMP Aluminium Cable Glands to prevent the electrolytic action of galvanic corrosion which can occur when dissimilar metals are coupled together

Note: Alternative materials are also available. Please refer to Table "E" of the Ordering References page detailed below. e.g. 20LN4 for M20 Stainless Steel Locknut, 050NPTLN4 for 1/2" NPT Stainless Steel Locknut.

Metric Locknuts Table

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  • View Imperial Table
Ordering Reference (Brass) Thread Diameter Minimum Thickness Across Flats Dimension Across Corners Diameter
16LN M16 x 1.5 3.2 22.0 24.2
20LN M20 X 1.5 3.2 24.0 26.4
25LN M25 X 1.5 3.2 30.0 33.0
32LN M32 X 1.5 3.2 36.0 39.6
40LN M40 X 1.5 4.8 46.0 50.6
50LN M50 X 1.5 6.3 55.0 60.5
63LN M63 X 1.5 6.3 70.0 77.0
75LN M75 X 1.5 6.3 85.0 93.5
90LN M90 X 2.0 9.5 106.0 116.6
100LN M100 X 2.0 9.5 123.0 135.3
115LN M100 X 2.0 9.5 130.0 143.0
Dimensions are displayed in millimetres unless otherwise stated


Ordering Reference (Brass) Thread Diameter "A" Minimum Thickness Across Flats Dimension "B" Across Corners Diameter "C"
16LN M16 X 1.5 0.125 0.858 0.927
20LN M20 X 1.5 0.125 0.936 1.011
25LN M25 X 1.5 0.125 1.170 1.264
32LN M32 X 1.5 0.125 1.404 1.516
40LN M40 X 1.5 0.187 1.794 1.938
50LN M50 X 1.5 0.246 2.145 2.317
63LN M63 X 1.5 0.246 2.730 2.948
75LN M75 X 1.5 0.246 3.315 3.580
90LN M90 X 2.0 0.371 4.017 4.339
100LN M100 X 2.0 0.371 4.797 5.181
115LN M115 X 2.0 0.371 5.070 5.476
All dimensions are in inches unless otherwise stated


NPT Locknuts

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  • View Imperial Table
NPT - Locknuts
Ordering Reference (Brass) Thread Diameter Minimum Thickness Across Flats Dimension Across Corners Diameter
(Min)
050NPTLN 1/2" NPT 0.150 0.945 1.039
075NPTLN 3/4" NPT 0.150 1.181 1.299
100NPTLN 1" NPT 0.189 1.417 1.558
125NPTLN 1-1/4" NPT 0.189 1.810 1.991
150NPTLN 1-1/2" NPT 0.197 2.165 2.381
200NPTLN 2" NPT 0.197 2.558 2.814
250NPTLN 2-1/2" NPT 0.394 3.148 3.463
300NPTLN 3" NPT 0.394 3.935 4.329
350NPTLN 3-1/2" NPT 0.441 4.498 4.948
400NPTLN 4" NPT 0.441 5.116 5.628
Dimensions are displayed in inches unless otherwise stated


Ordering Reference (Brass) Thread Diameter "A" Minimum Thickness Across Flats Dimension "B" Across Corners Diameter "C"
050NPTLN 1/2" NPT 0.187 1.053 1.137
075NPTLN 3/4" NPT 0.187 1.287 1.389
100NPTLN 1" NPT 0.187 1.599 1.727
125NPTLN 1-1/4" NPT 0.187 1.950 2.106
150NPTLN 1-1/2" NPT 0.195 2.340 2.527
200NPTLN 2" NPT 0.195 2.730 2.948
250NPTLN 2-1/2" NPT 0.390 3.120 3.369
300NPTLN 3" NPT 0.390 3.900 4.212
350NPTLN 3-1/2" NPT 0.437 4.446 4.802
400NPTLN 4" NPT 0.437 5.070 5.476
All dimensions are in inches unless otherwise stated


Additional information

CMP WP Locknuts_0310 Issue 1