Replace the pad on the spindle of any of Bessey’s cast iron, Omega, or all-steel screw clamps with their clamping force indicator and you can tell instantly if you’ve applied the correct amount of pressure. As you increase the clamping force, the red disk starts to disappear inside the indicator; when it disappears completely and you only see green you’re using the right clamping force.
Bessey manufactures two different indicators: the FIN250 which shows you when you’ve applied approximately 550lbs. (2500 Newtons) of force, and the FIN350 which shows when you’re close to 700lbs. (3500 Newtons) of force. Either of Bessey’s Clamp Force Indicators run about $20.