Extra Heavy Duty chucks refered as EHD are manufactured to cope with toughest working conditions. These are capable of carrying heavy loads. The height of bodies though little more, but it helps not break under the loads. The jaw-ways in body are of robust proportion which can withstand heavy loads. The diameter of screws is large enough to tolerate heavy cutting pressure and moreover large diameter of screws provide more contact area with thread of jaws. ACME threads of screws are very strong as the same have 29 degree taper. These do not break easily due to strength provided by large base of taper thread. Alloy steel is used in the manufacture of Screws, Thrust Bearings and Operating Key which are heat-treated to obtain wear resistance and toughness. Chucks from 6″ onward have double type thrust bearings of robust proportions which provide great strength. Operating Key, Mounting Bolts, Allen Key, Tap & Inspection Report is provided with each chuck.