An opportunity to teach… For blades which can be clamped on parallel surfaces, before tightening the blade in the vise, you should set the two screws like so:
1. Adjust the top screw to set the opening between the jaws to a distance very close to the blade thickness.
2. Then set the lower screw to put the space between the two jaws at the bottom to approximately the same opening. Remember that it can only push – it can’t pull.
3. Now use the top screw to clamp the blade into the position you need. You only need to tighten the top screw enough to keep the blade from falling out of the vise.
4. Turn the lower screw until it make contact with the opposite jaw. Then turn the lower screw another 1/4 to 1/2 turn past contact.
Except for very heavy or very long blades, you should never need more torque applied to the lower screw than it takes to turn the 1/4 to 1/2 turn.
The upper screw shouldn’t need to be tightened more than snug. It is intended only to set the jaw opening distance.
Full-flat ground blades require more finesse. Check out Josh’s video at https://knife.wickededgeusa.com/forum/6-techniques-and-sharpening-strategies/13084-bevel-angles#18509
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