You are currently viewing Mechanical Pencil Month – Day 17: Slide rules, OK?

Mechanical Pencil Month – Day 17: Slide rules, OK?

Another Slide Rule Saturday rolls around (whatever happened to the last one?) and having already used up my only slide rule pencil as well as my only pencil with slide rule features, once again I am compelled to think laterally for subject matter. My rule pencils are nothing to write home about (as a case in point, see the Kanoe ruler-pencil hybrid below), so that just leaves us with the slide part.

Kanoe mechanical propelling pencil with ruler

Fortunately, I managed to rustle up a handful of pencils that all use some kind of slide mechanism to propel the lead, pictured in approximately chronological order (more on which later).

Slider pencils

A.W. Faber spiral cedar-cased pencil

A.W. Faber Riddle patent spiral slider pencil

This is likely the earliest of the four, and is marked A.W. FABER around its barrel.

A.W. Faber Riddle patent spiral slider pencil barrel inscription detail

Its design is similar to the better known Lund pencils, which in turn were based on an 1848 patent by William Riddle, the son of Sampson Mordan’s erstwhile business partner Gabriel Riddle. Dated December 21, 1848 (yet another winter solstice patent!) the relevant section of Riddle’s patent No. 12,383 for “Improvements in the construction of ever-pointed pencils, writing and drawing instruments, and in inkstands and inkholders” reads as follows:

“2nd. Grooving the stem of a wooden ever-pointed pencil, so that a propeller with a helical thread can push the material out of the point.”

In some ways this is an unusual patent. William’s father had already patented a more sophisticated pencil with spiral mechanism in 1839, after parting company with Mordan. The motive behind William’s 1848 patent is revealed by a notice in the London Gazette of October 15, 1847 which tells us that Gabriel Riddle, Patent Pencil Manufacturer, had assigned his entire business to William Riddle of the Excise-office and Thomas Piper the younger, a London builder, presumably due to insolvency. It would therefore appear that his son’s patent of the following year was an attempt to salvage the business, which was ongoing in 1850 when the Illustrated London News reported on Riddle’s “Self-supplying Pencil case” and ever-pointed pencil in cedar. However, he seems to have disposed of his interest in the patent to Lund not long after.

It is unclear if the Faber pencil was supplied by Riddle or Lund, or else made in Germany under licence (or perhaps even without regard to Riddle’s patent). I have also found nothing in Faber’s catalogues relating to this pencil, so any information would be welcome.

Winsor & Newton’s Patent Ever-pointed Tubular Drawing Pencils

Winsor & Newton patent ever-pointed tubular drawing pencils set of four in Morocco case

This set of four pencils can be dated to a patent of 1858, in which year they were also heavily advertised in the press. The mechanism is simpler than Riddle’s, with a slide pushed along a slot in the side of the pencil.

Winsor & Newton patent ever-pointed tubular drawing pencil BB

Their distinguishing characteristic was the leads, which were hexagonal in section and, according to Winsor & Newton’s own advertisement:

“composed of Pure Cumberland Lead from the Borrowdale mines, firmly held in Tubular Holders; and being selected from lead of every gradation and depth of colour, of hardness and softness of texture, and of thickness of substance, they are alike fitted for the most delicate or the boldest hand, and will materially aid the Artist in the expression of freedom and power.”

Interestingly, no mention is made of their hexagonal shape, either in the advertisements or by a favourable review published in the Art Journal of February 1, 1858.

Winsor & Newton patent slider pencils both sides of inscription

While the initial outlay on the set of four pencils was seven shillings, each replacement lead cost three pence and they were sold in boxes of six at one shilling and sixpence.

With four different grades in the set (F, M, B and BB), each having its own particular size of hexagonal section, it is easy to see that the cost of replacement leads could soon add up, and being hexagonal they could only be purchased from Winsor & Newton.

Winsor & Newton patent ever-pointed tubular drawing pencils case detail

Instead, the Art Journal review – itself largely based on the copy from Winsor & Newton’s advertisement – focused on the qualities of the pencils:

“The Tubular Drawing Pencils are made of ebony, with silvered points; they are smooth and pleasant to the hand and very neat. We observe that economy has been consulted as well as quality, and that after the first expense of the holders these new pencils cost a comparative trifle”

Later that year, a second set of three further grades was introduced (HH, H and HB) aimed at architects and engineers, as advertised in The Engineer of August 1858. Presumably these also used hexagonal leads, although I have never seen this particular set, or any boxes of Winsor & Newton’s refills come to that.

The advertisements soon dried up, and it appears that the tubular drawing pencil did not last long in the increasingly competitive market for ever-pointed pencils. Their demise was surely accelerated by the proprietary lead format, making them the nineteenth-century equivalent of an inkjet printer, useless once their overpriced refills were no longer available.

Everite Pencil (patent no. 382121)

OK, so I got the order of the next two pencils mixed up in the photos! The Everite patent application, helpfully enumerated on the barrel of the pencil, was in fact lodged almost four years earlier than Wolff’s below.

Everite patent pencil barrel patent marking

It was taken out in the name of Friedrich Wilhelm Haack from Berlin, and covers the adjusting ring and helical lead holder that can both be clearly seen in Everite’s production model.

Everite patent pencil propulsion mechanism

Even though the pencils were very popular and sold in a wide variety of models, I have found little about either Haack or Everite online (a glass tube of Everite leads even turned up in my survey of refills on day twelve). Haack had several pencil patents to his name in the 1930s and after the war seems to have continued in the same vein with the German firm Haack Sparbleistift GmbH, which claimed to be the first German economy pencil factory. Once again, I am sure that further research on the subject would yield an interesting story.

Wolff’s Rex patent pencil

Wolff's Rex patent pencil

Wolff & Son was already a long-established name in the mechanical pencil business (remember their lead gauge?) when the Rex patent pencil was released. As indicated its box, it was manufactured after their merger with rival B.S. Cohen to form The Royal Sovereign Pencil Co. in 1920.

Wolff's Rex patent pencil box lid

Although the pencil itself is marked “PAT. PENDING” on its barrel, the British patent in question was applied for in October 1935 and granted in April 1937, leaving a relatively narrow window for the production of this particular example.

Wolff's Rex patent pencil barrel inscription

The main feature that differentiates it from the Everite pencil above is the inclusion of a locking mechanism for the ring, which constitutes the main object of the patent. By rotating the locking ring, the lead is held firmly at any position along the barrel to prevent it from accidentally retracting under the pressure of writing or drawing.

Wolff's Rex patent pencil disassembled slider mechanism detail

The downside to this innovation is that the ring must be unlocked again to advance the lead, and then relocked for use. Over prolonged periods of use, I can imagine this additional step becoming such an annoyance that the pencil was probably left in “Everite mode” most of the time.

As with the Winsor & Newton patent pencil, the Rex came with its own proprietary brand of leads – Fine Refill Blackleads No. 465, no less – although at least Wolff’s had the generosity of spirit to include a full pack of refills in the box.

Wolff's Rex patent pencil box interior

Being round in section, it is unclear how these differ from the other standard leads at the time, so perhaps it was just an attempt to generate brand loyalty. In any case, the Rex patent pencil seems to have ultimately gone the same way as Winsor & Newton’s, and is rarely seen today, which is a shame as it is a very sleek and attractive pencil.

In conclusion, for all their simplicity of construction and ease of use, slider-type pencils remained a niche category in the market. This was possibly due to the inherent weakness of the almost full-length longitudinal slit down the barrel. All but one of the models described above have a slit that extends fully to the rear of the pencil, closed only by a small screw-in end cap.

Slider pencils three end cap details montage

This was necessary both for the assembly of the pencil and its maintenance if something got jammed. Most of the pencil points also relied on a narrow slit to provide the required friction to prevent the lead from being pushed back into the case, Wolff’s Rex being the notable exception due to its locking ring.

Slider pencils detail point section detail

For these reasons, the slider mechanism is today largely consigned to refill erasers, such as the example by Pentel below – an ironic reversal of fortune for a pencil design!

Pentel ZE32 Clic Eraser Hyperaser in original packaging

Leave a Reply