1970 Wild NK2

The Wild NK2 (or rather NK21) new style.
Figure 1: The Wild NK2 (or rather NK21) new style.
This instrument entered the collection in March 2016. It is the successor of the 1951 Wild N2 in my collection. Clearly its design was given a complete makeover, making it a more modern looking instrument, showing the new design known from its successor, the Wild NA2, the later Wild N3 level and Wild TC1 total station.

Development
The Wild NK2 developed from Wild Heerbrugg's very first instruments, the Wild NII and Wild NKII levels and the later N2/NK2 models. The K in the model name indicates the presence of a horizontal circle (Kreis in German) like in this example here. The complete makeover shown here was introduced in 1969. The differences between the previous and the current model are mainly cosmetic. The telescope still has a fixed sun shade, and the coincidence vial is still fully encapsulated and read through a microscope (see figure 12). The housing that covers the technical parts of the instrument reflects the latest trends in industrial design. It shows nice integrated smooth lines without ponderous attachments like the circular vial in the previous models.

The most visually obvious technical difference was that the tilt screw moved from the ocular side to to the objective side of the instrument (see figure 9). To indicate the difference with its previous model Wild Heerbrugg referred to the instrument as the NK21 (and N21 for the version without horizontal circle).1

The Wild NK2 from the other side.
Figure 2: The Wild NK2 from the other side.
Accuracy
Also performance wise the NK2 saw some changes. The telescope went from a 28x power to 30x power, while the shortest focussing distance was reduced by 6 decimetres to 1.6 metres.2 When compared to its predecessor the accuracy with which the vial could be settled dropped from 0.5" to 0.8".2 This, however, seems to have been compensated by the higher magnification as the instrument remained capable to do a 1km double run with an accuracy of 2mm.2

The horizontal circle is centesimally divided (i.e. divided into 400 grad). It can be read directly to tenths of grads and estimated a decimal further (see figure 14). The orientation of the horizontal circle can be set by turning the black knurled ring on the base directly above the foot screws (see figure 9).

The Instrument
Judging the overall looks of the instrument it seems to have had a reasonable quiet life. It shows only little wear, mostly due to its contact with the box while being taken out and placed back. It has been dropped at least once, creating a small dent in the sun shade. The instrument dates from 1970, a year after its introduction in 1969. By this time some 1800 of these levels were manufactured.3 Judging from a written date inside the box, it was re-sold in 1978. It came with its original case and still is in full working order.

Notes

[1]: See the Product Overview Levels at the Virtual Archive of Wild Heerbrugg.
[2]: See the Wild Levels for every levelling task at the Virtual Archive of Wild Heerbrugg.
[3]: With many thanks to J. Dedual of the Virtual Archive of Wild-Heerbrugg for checking this for me.

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

The Wild NK2 new style with its predecessors from 1926 (left) and 1951 (centre).
Figure 3: The Wild NK2 new style with its predecessors from 1926 (left) and 1951 (centre).
 
The serial of the NK2 indicates it was made in 1970.
Figure 4: The serial of the NK2 indicates it was made in 1970.

The Wild NK2 is a reversion level, this is the normal locked setting.
Figure 5: The Wild NK2 is a reversion level, this is the normal locked setting.
 
The Wild NK2 is a reversion level, the lock is disengaged and the vial reversed.
Figure 6: The Wild NK2 is a reversion level, the lock is disengaged and the vial reversed.

The Wild NK2 just over halfway being reversed.
Figure 7: The Wild NK2 just over halfway being reversed.
 
The circular vial and locking mechanism of the new style Wild NK2.
Figure 8: The circular vial and locking mechanism of the new style Wild NK2.

The tilt screw (right) and horizontal drive screw (upper left) of the new style NK2.
Figure 9: The tilt screw (right) and horizontal drive screw (upper left) of the new style NK2.
 
Coarse aiming is done using this elongated V-shaped visor.
Figure 10: Coarse aiming is done using this elongated V-shaped visor.

The new style NK2 came with its original case, it was sold by Ahrin.
Figure 11: The new style NK2 came with its original case, it was sold by Ahrin.
 
The circle reading (lower left) and vial (upper left) microscopes.
Figure 12: The circle reading (lower left) and vial (upper left) microscopes.

The plate vial illumination reflector and circular horizontal circle illumination window.
Figure 13: The plate vial illumination reflector and circular horizontal circle illumination window.
 
A view through the circle reading telescope showing the centesimally divided circle at 399.59 grad.
Figure 14: A view through the circle reading telescope showing the centesimally divided circle at 399.59 grad.

A look at the coincidence vial with arrow indication (A), alomst correctly set (B) and level (C).
Figure 15: A look at the coincidence vial with arrow indication (A), alomst correctly set (B) and level (C).
 
An erected view through the telescope showing the cross-hairs and stadia hairs.
Figure 16: An erected view through the telescope showing the cross-hairs and stadia hairs.

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