Lubricants
Superbolt® Moly and Graphite based lubricants are used to insure
proper friction coefficient values on Superbolt® jackbolt torque
figures. They should be used for relubricating tensioners and can
be applied to the main threads as an anti-sieze compound.
Overview:
The torque-preload relationship of Superbolt® tensioners depends on the tensioner body and jackbolt materials, heat treatment, plating, lubricants, and other factors. Superbolt® engineers have performed extensive tests to determine the best lubricants for the various materials utilized by Superbolt®, Inc. In an emergency, a number of commercially available graphite or nickel based lubricant compounds can be used for jackbolt re-lubrication in the field, however, obtained preload may not be accurate.
Copper bearing compounds have not performed well as jackbolt lubricants.
Two custom lubricants, JL-G and JL-M are RECOMMENDED by Superbolt®. Both compounds have a higher solids content than commercially available compounds. They have performed better as jackbolt lubricants, particularly in high temperature applications. JL-G and JL-M are available in various container sizes and can be ordered directly from Superbolt®.
Proper Lubricant should be applied to the tips of the Jackbolts prior to installation.
JL-G Details:
JL-G is a lubricant paste made from selected flaky graphite and pure mineral oil. It has a relatively uniform friction factor of 0.130 under widely varying conditions.
JL-G is used in the assembly of most Superbolt® products. Tests show that as long as the lubricant is intact, the torque-preload relationship does not change appreciably in subsequent tightenings. Re-lubrication of jackbolts after lengthy or high temperature service restores Superbolt® products to their original performance.
JL-M Details:
JL-M is a lubricant paste with a high concentration of Molybdenum Disulfide powder. JL-M lubricant has the lowest coefficient of friction available commercially. Friction factors approaches 0.055, once broken in.
In addition to being used on several product lines, this lubricant is used on products with larger jackbolts (roughly 5/8” and up) enabling high bolt preload capacities with a low torque input (approximately 1/2 the torque of JL-G). This also helps reduce wear on sockets and adds the possibility of using smaller wrenches. JL-M should not be used on applications above 650° F.
As with all lubricants, it is important to apply some to the jackbolts prior to installation.