Bart and Tim Grönefeld, aka ‘The Horological Brothers’, are third generation
watchmakers. Like their forebears, they live and work in Oldenzaal in the
Netherlands. They are proud of their heritage as well as the nation they call
Inspired by the Dutch Delta Works, The Horological Brothers have conceived
their first sports utility watch, the aptly named 1969 DeltaWorks which also
references the year Bart was born. The model is designed to cope with the perils
of water ingress and shocks while still upholding the elevated standards of
horology and traditional craftsmanship that are synonymous with the Grönefeld
The dial of the 1969 DeltaWorks presents the essentials of time, namely, hours,
minutes and seconds. There is nothing superfluous. In fact, when designing the
watch, Bart and Tim were keen to ensure that the dial imparted information in a
clear, intelligible format. To deliver peerless legibility, day or night, the hands
and hour markers are treated with Super-LumiNova®, that produces a blue glow
in restricted light.
While the dial is highly practical it is still enriched with numerous details. For
example, the hour track sits on a higher plane than the central dial area and
small seconds display. The plump lancine-style hour and minute hands deliver
impressive readability even in the most challenging conditions. At the fulcrum of
the hands, the ‘centres’ are black polished to a gleaming conclusion.
The small seconds display features ‘60’, presented in an orange hue, a respectful
nod to the brothers’ homeland. Likewise, the country of origin is proudly
proclaimed at the base of the dial.
The 1969 DeltaWorks is presented in a 45mm stainless steel case, measuring
12.5mm in height. The case features an integrated strap that ergonomically
encircles the wrist, conferring a high degree of wearer comfort while appearing
smaller than its stated dimensions would suggest. The scale of the case endows
the watch with a generously proportioned dial area, augmenting legibility but
without appearing unduly large. Every aspect of the case has been carefully
Two inserts are integrated within each caseband, steadfastly secured to the main
body of the case. The inserts are offered in two formats: stainless steel,
matching the case material, or titanium shrouded in coloured FKM rubber,
designed to match the shade of the strap. A notable attribute of the latter option
is that there is less risk of the case band picking up annoying scratches.
Throughout the composition, the case juxtaposes brushed and highly polished
surfaces, contributing to the model’s notable allure.
A triple-seal, screw-down crown mitigates the risk of dust or water ingress. In
addition, the crown features an ingenious safeguarding system. When the
Grönefeld logo on the crown is perpendicular to the dial and pointing upwards,
the triple-seal, screw-down crown delivers maximum protection. The sapphire
crystals, to the front and rear, are thicker than normal and, by default, stronger.
As a result of the aforementioned details, the watch is water resistant to 100m,
making it suitable for an array of leisure pursuits, including swimming, sailing
When conceiving the 1969 DeltaWorks, Bart & Tim were keen to ensure the
watch was suitable for daily wear and compatible with an active lifestyle. With
this in mind, they decided it must feature a self-winding movement
encompassing the same exalted finishing as other Grönefeld timepieces.
Put simply, the brother’s wouldn’t countenance any compromises. As such, the
resultant movement, the calibre G-06, is worthy of the term ‘Haute Horlogerie’.
Brand devotees may recognise the calibre G-06, an automatic movement first
used within the company’s 1941 Principia Automatic. However, while many
elements have been carried over to the 1969 DeltaWorks, there are some
additional details which enhance robustness, imbuing this version with its own
For instance, a notable feature specific to this model is the distinctive oscillating
weight. The openworked architecture features four stainless steel arms,
presented in a double-spoke design. These arms are connected to an 18K gold
mass adorned with a wave motif. Each of the four arms is positioned beneath
the gold mass and projects beyond, sitting above a circular ledge. Should the
watch be subject to a sudden shock, the elongated arms will prevent the
oscillating mass touching the inside of the sapphire crystal or striking the bridges
The movement is intended for the most discerning watch collectors. The rotor is
completely hand finished and turns on ceramic ball bearings, preventing wear
and eliminating the need for lubrication. Meanwhile, the stainless-steel bridges
replicate the façades of traditional Dutch houses, termed ‘bell gables’. Each
bridge features a micro-blasted central section, framed with a hand-bevelled
gleaming edge. Some of the bridges also feature relief engraving. Each
movement is fitted with a plate engraved with ‘ΔW’ (signifying DeltaWorks)
along with its unique movement number.
The Grönefeld 5-arm, double spoke gear train wheels exhibit a contemporary
character, but their circular grained surfaces pay due reverence to fine
watchmaking tradition. Their design, as well as the bevelled escape wheel teeth,
prevent the oil from dissipating, thereby mitigating wear. The free-sprung
balance mitigates positional influence and delivers superior rate stability. The
escapement is adjusted to heat-cold, isochronism and six positions.
Gold chatons stand testament to the no-compromise specification of this
movement. In addition, the mirror polished screws feature chamfered rims and
slots. Numerous surfaces gleam, courtesy of the mirror-polishing which has been
patiently executed by time-served hands. The inventory of different decorations
includes snailed, grained, spotted and frosted surfaces, indulging the desires of
Once again, there are no compromises. Everything is reassuringly Grönefeld.
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