HYDRA-LOK Sealing Nuts

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HYDRA-LOK® Sealing Nuts

Zero Leakage At Threaded Joints

Patent Nos. 4,019,550 and 4,126,170.


“ Setting the standard for sealing nuts”

Seals Liquid Around Threads

At Bearing Surface Vibration-proof sealing of bolt and nut joints – eliminating the need for washers, surface preparation, packing or other measures. Our single piece design provides a more consistent and reliable seal, saves enormous amounts of time, reduces expenses, and contributes to overall performance efficiency. The patented design and tough virgin Zytel® nylon sealing insert is mechanically encapsulated within the nut face providing the convenience of a one-piece fastener.

Hydra-Lok Nuts

 Insert Compression Products:

  • 360 sealing pressure around threads and bearing surface.
  • Dampens vibrations-maintains preload.


HYDRA-LOK® sealing insert is unexposed and impervious to acids and solvents. When loosened, insert regains its original shape-ready for reinstallation! HYDRA-LOK® strong can be manufactured in special configurations from any commercial metal. All finishes available. Metric or special threads available.

AEROSPACE...HYDRA-LOK® can be made to adhere to Specification Mil-N-85615 Our Technical Advisory Service is at your disposal without obligation, and on request, we will furnish test samples and details of industrial applications already realized.

How it works:

HYDRA-LOK Sealing Nuts drawing

During installation the insert protrusion (1) slips outwardly against the bearing surface. A completed fold effect compresses the insert (2) to seal and lock as metal-to-metal contact is achieved.


  • Reusable, non-destructive
  • Free spin for easy installation
  • Special counterbore unnecessary
  • Metal to metal contact at bearing surface


  • One piece unit prevents assembly errors
  • Indefinite shelf life
  • Seals extreme PSI

Sizes Available

Standard Sizes: SteelMetric Sizes: Steel
5/16-18 5/16-2 M6
3/8-16 3/8-24 M10
7/16-14 7/16-20 M12
½-13 ½-20 M16
5/8-11 5/8-20  
¾-10 ¾-16  

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