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Mechanical Pencil Month – Day 3: Nestler’s German silver screws

As promised, today’s entry brings together Slide Rule Saturday and Mechanical Pencil Month in the hope of fostering a new spirit of love and cooperation between the two rival kingdoms. Unfortunately, I had already featured my most slide rule-y pencil in an earlier post, so it was necessary to approach the subject more obliquely. What better way than with a mechanical pencil from one of the greatest slide rule makers of all time, Nestler.

Nestler Kaliber mechanical pencil in box with container of two spare erasers

By the time today’s pencil was produced in the late 1980s, Nestler had not made a slide rule for twenty years. Indeed, the company responsible for it was a spin-off from the original founded by Albert Nestler of System Rietz fame. Set up in 1980 to capitalise on the rapidly-changing landscape of technical drawing and CAD systems, Nestler Graphics GmbH produced a range of mechanical pencils, of which the Nestler Kaliber seems to have been the flagship model. In spite of their slide rule heritage, drawing instruments were not a new area for Nestler, whose lettering systems and associated pens were already well established.

Nestler lettering set with templates and pens

Superficially, the Nestler Kaliber looks like a typical 1980s mechanical pencil, with its mannered high-tech design and oversized drop-shadowed KALIBER logo.

Kaliber by Nestler Germany mechanical pencil barrel text

Moreover, the “Registered German design and original Baird system exclusively from Nestler” touted by the short instruction sheet belies the fact that the pencil was actually made in Japan. It therefore came as a surprise to discover that it was not simply a rebranded import, but a design covered by multiple patents in the name of Nestler Graphics and one Munro Hugh Nicholas John Baird, upon whose eponymous system the Kaliber was based.

Munro Baird's 1988 patent drawings for the Nestler Kaliber mechanical pencil

The 1988 patent indicates that the Baird system’s unique functionality resides in the two semicircular slides on either side of the pencil. These can be moved independently and in opposite directions to advance the pocket-safe pencil mechanism at one end and the eraser at the other, the pencil slide also doubling as a pocket clip.

Nestler Kaliber mechanical pencil retractable pocket-safe point

With the pencil point extended, further pushes of the pocket clip slide will feed more lead. Pressing the red button on the side of the pencil retracts the writing point, a feature also seen on many Rotring models of the time.

Four views of the Nestler Kaliber mechanical pencil

For a pencil produced by a seasoned slide rule maker, this use of lateral sliding elements seems somehow appropriate. However, it is not the main reason I chose to feature this particular mechanical pencil on Slide Rule Saturday. For this, we need to go back to the beginning of the twentieth century, and the patent that launched Nestler as a major slide rule innovator in their own right.

In 1901 Nestler received DRGM 164885 for fixing the celluloid facings of slide rules to the wooden body using German silver screws. Celluloid scales had been first introduced by Dennert & Pape, who successfully patented their use in 1885. It was also D&P who manufactured the slide rule bodies used by Nestler in their early years. Nestler, on the other hand, had the superior dividing engines, and returned the favour by supplying D&P with precision-divided scales.

This partnership continued into the early 1900s, even after Nestler’s introduction of screwed facings, but in retrospect the DRGM was the first sign of their intention to plough their own furrow. Subsequent patents saw the two firms move in different directions, with Nestler no longer dependent on D&P for their slide rule bodies. However, German silver screws remained a prominent feature on slide rules from both makers for at least the next couple of decades.

Nestler Mannheim slide rule c.1901-2 and Nestler Kaliber mechanical pencil

The slide rule pictured above is from the earliest period of Nestler’s patent, circa 1901-2, and clearly shows the paired German silver screws (later increased to three, with an additonal screw on the slide) at both ends of the stock. Similarly, both slides of the Kaliber pencil are fixed with a pair of screws that bear an uncanny resemblance to the originals. In light of Nestler’s history, it is impossible to see this as anything but an homage to the German silver screws that were the hallmark of their early success.

It makes what would otherwise be an odd fish of a mechanical pencil into a touching tribute to a family firm, all the more poignant because within the space of five years Nestler had filed for bankruptcy. While the Kaliber can not exactly be regarded as the swansong of the great slide rule maker, is remains a fascinating product of its time, looking simultaneously to the past and future. Sadly, that future was not one in which Nestler was to play a role.

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