If you’ve ever tried grabbing a shaft lengthwise with a normal set of locking pliers, you’ll notice they don’t hold it very well — the shaft can slip from side to side in the jaws. With this in mind, Snap-on designed their new locking pliers with grooved jaws designed especially for holding such objects.
Snap-on gave their locking pliers serrated milled teeth just like other locking pliers, but they cut a V-groove longitudinally in one jaw to hold round objects. This groove prevents side-to-side movement because the jaws contact the object at three points instead of two. They also taper the groove, making it wider as it goes deeper into the jaw so the larger the diameter of the object, the more securely the jaws hold it.
For normal gripping, the convex jaw pushes objects against the fixed flat jaw, which results in higher clamping force. Plus, a recessed area behind one of the jaws allows you to hold irregular or angled objects.
You’re gonna pay $30 for these grooved-jaw locking pliers — more reasonably priced than we would have expected from Snap-on.