0314
   PLANE PARALLEL PLATE MICROMETER   
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  Surveying Instrument Collection 

Maker

CARL ZEISS, Oberkochen, Germany

Model

5 mm Plane Parallel Plate Micrometer for Zeiss Ni2 Level

Serial Number

n/a

Dimensions

75 x 86 x 165 mm

Image

Description

This PPP micrometer attaches to the telescope of the Zeiss Ni2 automatic level. It allows to move the line of sight 2.5 mm up and down. The device is used in precise levelling with invar line staffs graduated at 5 mm intervals.

The range of the micrometer is 11 units (1 unit = 0.5 mm). The micrometer is graduated in steps of 0.5 units on the metal readout scale. Interpolation to 0.05 units (±0.025 mm) is possible.

The invar staffs for this PPM must be graduated and numbered in 0.5 cm steps. In precise levelling, the staffs are read directly to the half-centimetre (since each half-centimetre line carries a number) and the decimals of the staff interval (5 mm) on the micrometer drum. The booking and the computations are carried out in terms of the (1/2 cm) staff graduation intervals. The final levelled height differences are obtained by division by 2.

The double run levelling precision of the Zeiss Ni2 with plane parallel plate micrometer and invar staffs is quoted as ±0.3 mm * SQRT(km).

Order Number 704402

Weight: 0.9 kg

History & comments

Device is post 1950.

Conservation

In leather tubular container

Condition

PPPM and container in excellent condition

Remarks

Box marked Fa67, P/C(plat card) 7336

Micrometer engraved "ZEISS West Germany"

Dates

Catalogued in 2012 by JMR. Photo by JMR.

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