What is a Swivel Mount?

Also known as Fedorov stage. It is an additional instrument mounted on the polarizing microscope stage. It consists of three, four, or five rotation axes. The sheet is sandwiched between a pair of glass hemispheres on the rotation table. With the rotation of each rotation axis, the crystal is tilted and rotated in space to achieve the required orientation for accuracy. Determine optical constants of crystals and identify minerals.

The turntable consists of a metal shaft, ring and glass hemisphere system. The upper and lower glass hemispheres hold thin slices of rock so that they can rotate at will in three dimensions. A five-axis rotary table produced by the Leitz plant in Germany is used as an example to introduce the structure of the rotary table.

Remove the microscope objective lens, sheet clamp, and metal disc in the center of the objective table; raise the microscope tube (or lower the objective table) to the maximum, and the objective table is locked at 0 °; On the right side, hold the rotating stage gently on the object table, and align the two circular holes on the base with the two screw holes on the object table. Those who attach the chassis should tighten it. Those who do not have this kind of chassis should not tighten it first, so that the base can be moved when the center of the turntable is calibrated, and then tightened after calibration; After the rotation stage is installed, return the axes of the rotation stage to zero (the N axis is not necessary, the same applies hereinafter), that is, the H, K, and I axes are located at 0 °, and the M axis is fixed at 90 °. ^[1]

Rotary table is a kind of precise and precious and easily damaged instrument, especially the hemisphere and round glass sheet made of optical glass, which has extremely low hardness and is easy to wear. Therefore, when operating, be sure to strictly abide by the operating regulations and laboratory regulations, and pay attention to the maintenance and maintenance of the instrument at any time.

First, before installation, clean the hemisphere, round glass, rock flakes, etc., and do not attach dust, otherwise the dust particles will cause microscopic scratches on the hemisphere and round glass. The edges of the sheet used should be smooth, and the cover glass should be completely smooth.

2. The cover glass must be installed with the cover glass facing up, otherwise the focus cannot be achieved, and the accident of the objective lens hitting the hemisphere is very likely.

3. When installing the stage, try to raise the lens barrel (or lower the objective stage) as much as possible, and at the same time remove the objective lens to avoid collision between the upper hemisphere and the microscope.

4. When installing the upper hemisphere, do not overtighten the fixing screws to avoid crushing the cover glass. Scratching the hemisphere. At the same time, do not drip too little liquid paraffin, otherwise there will be no lubrication between the hemisphere and the sheet, which will cause wear.

5. When focusing on time, you must first lower the lens barrel (ascending the object table), and observe the distance between the objective lens and the upper hemisphere side by side, until it stops when it almost touches, and then look at the field of vision and slowly raise the lens barrel (or lower the object). Table), focusing on quasi-minerals, this will prevent the lens from hitting the spherical surface.

6. The locking screws of each axis of the rotary table (especially the most commonly used H-axis) are easy to wear and tear. You must pay attention to maintenance. Remember to loosen the corresponding locking screws before turning each shaft. Never rotate the rotating shaft with force in the locked state. During operation, the movement should be light and light. Use the force of the fingertip to rotate the axes. Do not use wrist force, let alone arm force.

Seven, all work such as assembling and disassembling the table should be carried out on the table top covered with rubber pads. The used optical components (hemisphere, round glass) must be wiped clean with lens paper (or absorbent cotton) dipped in a mixture of alcohol and ether, leaving no oil stains. Metal parts should also be wiped frequently, not to mention liquid paraffin sticky parts, it should be wiped with alcohol-ether mixture in time. ^[1]