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Concave MF Locknuts

Used in conjunction with a regular square nut, the concave MF Locknut spins freely from either side into place with the fingers.  When the MF Locknut touches the nut, an additional one-half to three-quarters of a turn with a wrench locks it securely. The additional turns deflect the nut threads from their true helix and causing them to firmly grip the bolt threads; vibration cannot shake it loose.  No special wrench is required. 

Improved corrosion resistant options are available!

Better: TDG coated items


Below items are RUS approved.

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Concave MF Locknuts

Catalog Number Description Weight/100 (lbs)
J8581 3/8" Square 1.3
J8583 5/8" Square 4.2
J8584 3/4" Square 5.4
J8584-1/2 7/8" Square Locknut nuts 8.1
J8582 1/2" Square 3

TDG Concave MF Locknuts Dim Drawing Image

Table below are items protected with zinc applied by the Thermal Diffusion Galvanizing (TDG) process (reference ASTM A 1059). Corrosion protection and service life for TDG items is greater than that provided by standard hot dip galvanizing. 

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TDG Concave MF Locknuts

Catalog Number Description Weight/100 (lbs)
J8583T 5/8" Square 4.2
J8584T 3/4" Square 5.4

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