Product details:

Quick setup and robust rails and clamping surfaces allow speed and strength. Bessey Rapid Action bar clamps combine quick set up, 'no twist' clamping and high clamping pressures: The double spindle mechanism features an internal thread that moves the clamping bolt twice as far per turn as a standard ACME threaded spindle. The clamping bolt and pressure plate are manufactured from a single piece with no seams for debris to enter. The clamping bolt is guided firmly in the barrel for direct "no twist" pressure to prevent parts from shifting when pressure is applied. A hardened steel set screw meshes with the serrations on the rail for anti slip action. As more pressure is applied, the more the set screw engages the rail. Available in 12", 24" and 36" lengths with 4" or 6" throat depth. The German steel rails on the 4" throat models are 1-3/16" wide by 5/16" thick and on the 6" throat models 1-3/8" wide x 23'64" thick. 4" throat models can produce up to 1320 lb clamping pressure. 6" throat models can produce up to 1620 lb clamping pressure. Germany.