Beyond the 30° Flank
HKR locks at NIKKI's unique flank angle rather than the conventional 30° contact, keeping the difference between locking torque and surface pressure within 10%. That uniformity prevents loosening, overheating, and noise on high-speed assemblies.
The full explanation is on the Ultra-Uniform Locking Series page.
Body Height From 8 mm
Fits a shallow axial envelope
No Thrust Washer or Keyway
Fewer parts, simpler assembly
Ground Contact Surface and Thread
High-precision grinding process
3 or 6 Set Screws Per Nut
M4 to M12. 2.2 to 60 Nm max
Where HKR Locknuts Are Used
Compact Spindle Bearing Retention
Ball Screw Support Bearings in Shallow Housings
Robot Joint Drives and Reducers
Linear Stages and XY Tables
HKR Specifications
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Products in this Ultra-Uniform Locking Series
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Questions About the HKR Locknut
The HKR is the low-profile locknut in NIKKI's Ultra-Uniform Locking Series, in metric threads from M15 x 1 to M200 x 3 with body heights from 8 mm and 0.002 mm maximum axial run-out. The questions below are the ones buyers ask before a first order.
Contact UsThe maximum axial run-out is 0.002 mm. Both the thread and the contact surface are finished by high-precision grinding, which is what holds the run-out to this level.
Body height runs from 8 mm at M15 x 1 to 32 mm at M200 x 3. That's 6 mm thinner than the equivalent HKF at the small end of the range, which is often the difference between fitting a shallow bearing housing and redesigning it.
Each size lists a catalog maximum per screw in the dimension table, from 2.2 Nm for M4 set screws up to 60 Nm for M12. Tighten gradually and alternately rather than one screw fully first.
Add L to the order code for a left-hand thread (HKR30x1.5P-L) or U for an inch thread (HKR30-U18). Standard right-hand metric versions are ordered by the plain name.
HKF suits assemblies where axial space isn't the constraint. It's the standard-height version of the same series, with larger set screws at the small end of the range, M5 against HKR's M4 at M15, for higher locking torque.
No. The unique flank angle locking works directly between the set screws and the thread flank, so neither a thrust washer nor a shaft keyway is required, and the nut is reusable if handled properly.