HARDLOCK Nut - Precautions
Features of the HARDLOCK Nut
- When reusing a nut
When reusing a HARDLOCK Nut or Bolt, first fasten the first (convex) nut followed by manually screwing on the second (concave) nut until the two come into contact. A slight gap should remain. If there is a gap of about 1 pitch, the nut/bolt can be reused. If there is a gap of much less than one pitch or there is no gap, do not reuse .
- When fastening with zero or extremely low torque (stress)
Fix the first (convex) nut with a wrench, then fasten the second (concave) nut using the torque specified by HardLock. Note that if the first (convex) nut is not fixed, it may rotate with the second (concave) nut.
- If the second (concave) nut is tight on the first (convex) nut with a fastening torque lower than the specification torque
The HARDLOCK Nut and HLB are produced with the tolerance set to JIS 2 grade (ISO 6H). In the event that the product (JIS 3 grade or ISO 8g) has a bolt or shaft lower than the JIS 2 grade or ISO 6g minimum value, the tolerance between the bolt and nut will be greater, such that it will be possible to fasten the second (concave) nut with a torque less than the HARDLOCK standard value. We request that you replace that bolt or shaft with a JIS 2 grade or ISO 6g product as the looseness effect will be inadequate. If replacement is not possible (such as because a special product is being used), please contact us.
- Hot-dip galvanizing
Because of the thick galvanizing layer that results from hot-dip galvanizing, overtapped HARDLOCK Nuts are used. Such products may not fit well with products having a thin coating such as produced by electrogalvanizing. Please confirm that nuts and bolts have the same surface treatment before use.
- If HardLock's product does not fasten to your bolts or shafts
The HARDLOCK control system the old JIS grade 2 (ISO 6H) for the screw grade of its nuts and HLBs. If the bolts and shafts you use also conform to the old JIS 2 grade (ISO 6g), they will fit without any trouble, but if the bolts and shafts are produced to fit to general nuts, some may not fit to specification. If there is a fitting problem with our products, we ask that you use an instrument such as a ring gauge to determine whether there is a specification problem.
- Surface treatment coloration
Parkerizing, also known as phosphating, is a paint undercoat and does not provide corrosion resistance. Please be aware that in some environments, a Parkerized surface may rust in a week or sooner.
- Parkerizing (phosphating) and corrosion resistance
The surface treatment process involves variables such as temperature, concentration and immersion time. Depending on the exact mix, there may be some difference in the color of the plating. Regardless, however, this has no effect on the corrosion resistance of the plating.
- Hardlock specification changes
At HARDLOCK, we work day in and day out to make sure the HARDLOCK Nut and other products live up to our customers' expectations. In our pursuit of perfection, we may change the basic dimensions, engraved dimension tolerances and other specifications. In cases where there is not a large change in functionality, we strive to notify our customers in advance about the minor changes, but due to restrictions on our resources, we recommend checking our website from time to time. We thank you for your understanding.
- Stainless steel lubrication
As HARDLOCK generally applies a special lubricant we have developed to our stainless steel fasteners, no lubricant application should be needed. In addition, the added application of a general lubricant may actually decrease the lubrication of the fastener, so please be careful in this regard. (An exception is our HL Spray, which may be used without loss in lubrication.)