Workholding device

1. What should be done to a magnetic chuck when it becomes unevenly worn?

2. What workholding device can extend the magnetic field of the magnetic chuck and quickly position and hold work at a 45-degree angle?

3. What workholding device can be used when grinding very precise angles other than 45 degrees?

5. Briefly describe the method for grinding two perpendicular surfaces without repositioning the workpiece.