Williams & White 1,390 Ton Particle Board Press

Problem: The platens of this press are loaded against a shoulder on four 9-1/2" columns. The working load of 700,000 lbs per column is taken up against the original forged nuts. Large size nuts are difficult to tighten with existing methods which, in this case, were not doing the job. Over time, a difference in the distance between platens of 1/8" in one corner had resulted, and this was causing a lot of extra costs to meet tolerances of the finished product. In order to straighten this, the nuts had to be tightened to hold the platen firmly against the column shoulder again. Several attempts were made to turn the nut in either direction using hammers, hydraulic rams and fixtures, but they were seized tightly in place and had to be burned off. The column threads are 9-1/2" - 4tpi.

Solution: Once the old nuts were removed, the Superbolt® Multi-Jackbolt Tensioners were threaded easily into position and a preload of 900,000 lbs was applied in about 20 minutes using 1/2" drive impacts and hand torque wrenches (jackbolt torque equals 150 ft-lbs). The customer saw an instant improvement in the quality of product coming out of the press as it has held square & firm with the Superbolt® Tensioners. In the future, if the nuts need to be checked, adjusted or tightened, it is a simple matter of using a hand torque wrench to verify torque.

 

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