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Mechanical Pencil Month – Day 14: Compass inserts

As mentioned in day twelve’s survey of lead refills, A.W. Faber’s polygrade leads revolutionised the compass pencil insert, with 2 mm quickly becoming the standard size of fitting. Mostly these fittings required the user to clamp the lead in place manually, either in a split sleeve tightened by a set screw, or by jaws fitted with a screw-on collar (possibly another E.O. Richter innovation). Some transitional drawing sets with the old-style cedar pencil holders provided additional metal inserts that enabled the use of Faber’s leads in the old fixture. Alternatively, the bare lead could be wrapped with a strip paper to the required diameter, a reassuringly low-tech solution.

It was only with the introduction of tubular technical pens and compasses with dedicated holders, such as the early Rotring range made for them by Haff and Riefler, that the problem of how to accommodate pencils once again reared its ugly head.

Rotring's early compass range from their 1969 English language catalogue

Rotring’s initial answer was an optional lead insert of the jaws-and-collar type, in which the lead had to be manually fixed. This seemed to serve its purpose well enough until the appearance of the first fineliner pencils with their thin polymer leads in the mid 1960s. Due to the fragility and fineness of the lead, these pencils depended on push-button clutch mechanisms, with manual adjustment no longer a viable option.

Consequently, the bulk of mechanical pencil compass inserts date from the 1970s or later. Of the examples in my collection, most are 0.5 mm fineliners, but I also have inserts in 0.3, 0.7 and 2 mm lead holder formats from both Rotring and Staedtler. From the mid to late 1980s, both companies sold compass sets that included mechanical pencil inserts in their house colours of “Weinrot” (wine red) and blue respectively, as did Faber-Castell who stuck with their trademark green. Inserts were also sold individually, Rotring’s supplied to retailers in boxes of five.

Rotring mechanical pencil compass inserts 2 mm and retail box

Staedtler, on the other hand, offered this Circofix set containing three different lead sizes and a 4 mm shank compass adaptor for non-technical pen instruments.

Staedtler Mars Circofix three mechanical pencil compass insert set

Staedtler also sold mechanical pencil inserts with a 4 mm shank, designed to fit directly into traditional master bow type compasses. The earlier of these had a twist-feed mechanism for propelling the lead and a conical point like a small version of their Micrograph pencils.

Staedtler Mars 0.3 mm mechanical pencil compass insert in tube

Subsequently the design changed to a more modern stepped cylindrical point, actuated by pushing the entire front section of the insert upwards towards the shank, the lead advancing incrementally with each click.

Staedtler Mars 0.5 mm mechanical pencil compass insert in plastic case

To my knowledge, the major Japanese fineliner manufacturers such as Pentel did not make dedicated compass inserts, nor am I aware of any mechanical pencils from traditional drawing instrument makers such as Kern or Riefler. However, two of my Haff ellipsographs came with short all-metal mechanical pencil inserts with twist-feed lead advance.

Haff ellipsograph mechanical pencil inserts by Uchida

The insert belonging to the regular model 97 ellipsograph (left) was supplied in a Haff plastic bag, while the other from my much larger model 98E (right) is a Uchida KD-Type instrument. Both are very similar in construction, suggesting that Haff sourced all of its pencil inserts from Uchida.

Lion Drawing Instruments compass set with pencil insert

Mechanical pencil inserts are also commonly found in modern Japanese compass sets, such as the Lion Drawing Instruments example pictured above. These inserts are generally similar in design to the Staedtler 4 mm shank inserts, which were also made in Japan.

Mechanical pencil compass insert with 4 mm shank from Lion Drawing Instruments set

In many ways Japan seems like the land that CAD forgot, with most of today’s professional mechanical pencils – including those sold by Rotring and Staedtler – now manufactured there.

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