1965 Wild Heerbrugg NK01

The Wild Heerbrugg NK01
Figure 1: The Wild Heerbrugg NK01
Together with the 1965 Wild NK10 the instrument shown here is a bit of a stranger amidst the collection. Whereas most of the optical geodetic instruments in the collection either come from the high-end of the spectrum or have been playing an important role in the development of them in general, the NK01 is a very simple builder's level for tasks requiring little accuracy.

Together they were however the first two geodetic instruments in the collection and as it is nice to have the whole 'baseline' of levels from the N0 up to the N3 that Wild Heerbrugg created over the years justifies their presence. In addition to that they are coincidentally the same age as I am.

Development
Just like with the theodolites Heinrich Wild started building levels with model number 2. The first theodolite Wild produced was thus the T2, while the first level he produced was the N2 (or rather NII as Wild used Roman numerals for the levels in the early days).

The Wild Heerbrugg NK01 from the other side.
Figure 2: The Wild Heerbrugg NK01 from the other side.
From these instruments he first stepped up to even better instruments as the T3 and the N3 before developing instruments with lower accuracy to facilitate a wider market.

Accuracy
Being a builder's level one can not expect the highest accuracy from it. The telescope has a 18 times magnification with a 100 times stadia constant for the stadia hairs. The horizontal vial has an accuracy of 60" per 2mm run and can be levelled with an accuracy of 10". As a result of this a 10 millimetres standard deviation for a kilometre double run is all that can be achieved.

The instrument
When the instrument arrived it was in a sorry state. Luckily enough it came together with two NK10s, one of which provided several parts to restore this one and the other NK10. The vial reading mirror was gone and was replaced by a non-original brass one. The case was missing, but the instrument fits an old NK10 container in the collection well.

If you have any questions and/or remarks please let me know.

The mirror for reading the vial.
Figure 3: The mirror for reading the vial.
 
The mirror of the vial folds down to protect it.
Figure 4: The mirror of the vial folds down to protect it.

Three capstan screws allow adjustment of the circular vial of the Wild KN01.
Figure 5: Three capstan screws allow adjustment of the circular vial of the Wild KN01.
 
Two capstan screws allow adjustment of the plate vial of the Wild NK01.
Figure 6: Two capstan screws allow adjustment of the plate vial of the Wild NK01.

The horizontal circle of the NK01.
Figure 7: The horizontal circle of the NK01.
 
The serial indicates it was made in 1965.
Figure 8: The serial indicates it was made in 1965.

The Wild NK01 and NK10 compared.
Figure 9: The Wild NK01 and NK10 compared.
 
The inverted view through the telescope.
Figure 10: The inverted view through the telescope.

Surveyor's crosses Geodetic Sextants Theodolites Total Stations Levels Standards Tools Firms
20th c. hydrostatic level 19th c. water bottle level 19th c. Secrétan Egault 19th c. Tibaut Lenoir 1928 Carl Zeiss Nivellier I 1926 Wild NKII 1924 Carl Zeiss Nivellier II 1948 Wild N1 1932 Carl Zeiss Nivellier III 1951 Wild N2 1965 Wild NK01 1965 Wild NK10 1961 Wild N3 1970 Wild NK2 1977 Wild N3 1999 Wild NA2-GPM3 20th c. Cowley 1960s Jenoptik Koni 007 1960s Zeiss Opton Ni 2