The third type of clamp replaces the worm drive with an M8 bolt and these are used on smaller diameter couplings requiring higher hydrostatic performance. A suitable lubricant is used on the bolt to reduce friction and increase the screw efficiency and also to prevent galling associated with stainless steel. These can be tightened up to 20Nm. These are used on small diameter Magnum Couplings.
Visit the Fernco website for more information on Bolted Clamps