Hardlock Bearing Nut FAQ

Self-locking Performance FAQ

What is the best feature of the Hardlock Bearing Nut?
The Hardlock Bearing Nut provides a sufficient self-locking effect for any kind of adverse condition without the need to change the target application specifications.
To what extent does the self-locking effect differ between the Hardlock Bearing Nut and a regular bearing nut?
Unlike a hexagon nut, a Hardlock Bearing Nut cannot be tightened with a strong force. The ability to manage the Hardlock Bearing Nut with an extremely low torque puts it into a league of its own.
Is there any change in the self-locking effect if the concave nut is tightened first?
No, there is no change in the self-locking effect if the concave nut is tightened first. Some customers tighten the concave nut first when there are few screw threads. In general, we recommend tightening the convex nut first if the target application is exposed to strong loads.
How does the self-locking effect of the Hardlock Bearing Nut measure up to a general bearing nut and toothed washer?
The Hardlock Bearing Nut can withstand more shock vibration than is needed to damage a tooth washer in the NAS vibration test.
Where is the Hardlock Bearing Nut often used?

• In places subject to heavy loads
• In places where there are repeated forward and reverse rotations
• In places with vibrations
• In places where maintenance is difficult after attachment
• In places where a high torque cannot be used for tightening


Product Selection FAQ

How should I find the shape and type best for my target application?
In addition to the standard and thin types, the Hardlock Bearing Nut is also manufactured to customer requirements. Check the dimension table to see if the Hardlock Bearing Nut is right for your target application.
Does the target application require a special bolt/shaft for use with the Hardlock Bearing Nut?
The HLB is normally produced with an ISO tolerance class of 6H, but we also provide HLBs tailored to the tolerance class of the bolts/shafts for your target application.
The HLB is normally produced with ISO 6H tolerance zone class.
Does the shaft require a keyway?
No. Although the HLB can be used with shaft having a keyway, it is not necessary, and a toothed washer is not required, either.
Is the HLB affected by the temperature of the use environment?
The three standard materials used for the HLB  are low-carbon, medium-carbon and stainless steel. If your target application has a temperature lower than -100° C (-148° F) or higher than 300° C (572° F), other materials and/or surface treatments should be considered. Contact us for a consultation.
How do you control the torque of the secondary nut?
Refer to the tightening torque table to find the value for the relevant nut size.
Are the lower and upper surfaces of the standard HLB polished?
The upper and lower surfaces are finished but not polished.

Installation FAQ

Should lubricant be applied to the bolt/shaft?
Lubricant may be used if necessary, as it does not affect the self-locking effect. Lubricant is particularly helpful in HLB detachment.
Is a special tightening tool required to install the HLB?
No special tightening tool is required.
Is it necessary to hold the convex nut in place when tightening the concave nut?
If you have tightened the convex nut to the bearing surface, then the convex nut does not need to be held in place while tightening the concave nut. However, if the convex nut is tightened at an intermediate position on the bolt/shaft, it should be held in place while tightening the concave nut to prevent both nuts from turning.
After tightening the HLB, is it safe if there is a gap between the convex and concave nuts?
If the concave nut is tightened to our recommended torque, then the HLB will provide a sufficient self-locking effect even if there is a gap.

Maintenance after Installation FAQ

Is there anything special to keep in mind when removing an HLB?
Apply lubricant to the bolt and the HLB. First remove the concave nut while holding the convex nut in place, and then remove the convex nut. Be aware that there is a risk of seizing if you attempt to remove the concave and convex nuts at the same time.
What should I look for when reusing the HLB?
Whether an Hardlock Bearing Nut can be reused depends on environmental conditions, the HLB material and the target application. Before reusing the Hardlock Bearing Nut, manually install the concave nut onto the convex nut and make sure that there is a gap of one thread pitch. If there is not, please refrain from reusing. Contact us if you have any questions regarding reuse.
Can the HLB be painted after installation?
Yes, painting the HLB does not affect the self-locking effect.