The Graduated Grinding Jig, shown in the illustration, is used for grinding Transmission Electron Microscopy (TEM) discs to accurate, predetermined thicknesses.
The time to perforation during electropolishing is reduced and the quality of the thin foils is improved if discs are less than 0.010in. (0.25mm) thick. Electropolishing conditions can be reproduced more easily when the discs have similar thicknesses.
The base of the recess into which the disc is placed, on the right in the illustration, is a plunger that is advanced or retracted by the internal "click stop" mechanism in steps of 0.001 in. (0.025mm) when the knurled knob is turned. The thick disc is placed into the recess and the knob is turned until the disc protrudes from the base. The Jig is rubbed on wet abrasive paper to reduce the disc to the desired thickness.
The heavy stainless steel body makes the Jig easy to hold and control. The user's hands are shielded from ionising radiation.