We recently had a customer with a similar problem, which was resolved with one phone call. You should contact us directly or distributor/rep for assistance. These clamps, when properly used will last for years. The 2-56 screw has a max torque of .5 ft lbs. We recommend a cordless drill that has an adjustable torque setting and a ball-end hex key, keep the trigger pulled for quick loading/unloads...and same torque every time.
If the clamp is continually over expanded the segments will break or not fully retract. To properly machine clamps for long life...expand .002-.005 over relaxed dia. and machine to your bore size. This will allow easy load/unload and max. line contact.
Feel free to contact me if problems persist. Customer satisfaction is our #1 priority!