A most suitable pencil for desk work

The manga series Oh My Goddess was originally published from 1988 until 2014. I am only familiar with the early comics from this series, so the following might not apply to comics from the later years – but there was always exceptional detail on products and technology. Specific products and their features were often being mentioned or hinted at. A lot of this information was about cars, motorbikes, cameras, but you can also see calculators and mechanical pencils in this series, as seen in the examples below.

Keiichi using a Sharp PC-1401 calculator/computer and a so far unidentified mechanical pencil (Oh My Goddess #5, p.39, read right to left)

I am not sure if the pencil from page 39 is supposed to be the same as the one from page 71, but it’s a great close up drawing. The sleeve seems, proportionally, rather slim, though.

There were many different version of the Zebra Knock Pencil. Some versions of the M-1300 had the text “A most suitable pencil for desk work” printed on the side. As far as I can tell the Zebra Knock Pencil is not being sold anymore and Zebra has replaced this model with more high-end mechanical pencils.

Urd is using a Zebra Knock Pencil (Oh My Goddess #5, p.71, read right to left)

The images have been taken from the English version of Oh My Goddess, published by Dark Horse Manga as Volume #5. I believe that the use of these images falls under “fair dealing” as described by the UK Copyright service.

Zebra’s Tiny TS-3

Ten years ago I bought Zebra’s tiny TS-3 mechanical pencil. Back then it cost £2.50. These days it’s a bit more expensive, but is still quite affordable.

You’d think that a pencil with such a small size, it’s only 10 cm long and has a diameter of just over 5 mm, it can only be used if no better pencil is available..

..but the truth is that it’s much more comfortable to use than many other emergency pencil, i.e. the kind of pencil that comes with some of the Swiss Army Knives.

In May I put a video review online that provides some more information about this pencil.

Compared to a selection of other mechanical pencils the Zebra TS-3 is tiny

It might not be your best choice for a daily writer, but it’s certainly a good choice for a pencil you can store in a pocket or bag so that you have a mechanical pencil when you need it. The comfort to size ratio is certainly better than what you might expect.


Zebra Sarasa - Chupa Chups Flavour

Smelly Pens – Zebra Sarasa Chupa Chups Edition

Welcome to what is probably my first gel pen focussed blog post: a quick look at the Zebra Sarasa Chupa Chups Scented Pens – and at the Staples gel pens.

Staples Sonix gel

The Staples Sonix gel pens were on offer and only 50p each: they are a mixed bag. The fluorescent pink usually writes well, other colours do sometimes smudge and don’t always have a good ink flow… This is very different to the experience Bob from my pen needs ink had. I’m not sure whether this is because of poor quality control, the difference between different colours, declining standards or the fact that my pens were too old, i.e. stored too long in the store before I bought them.

Staples Sonix Gel
Staples Sonix Gel

The performance of the Staples Sonix made me think of this video from the Wall Street Journal:  What Took China So Long to Master Ballpoint Pens?

Zebra Sarasa – Scented Chupa Chups pens

The Sarasas, on the other hand, are excellent performers. My green / yellow / red pack, bought from this seller, smells very nice, but the orange / blue / black pack has an artificial, bought here, slightly unpleasant smell to it. $9.50 for a pack of three seems a good price.

Zebra Sarasa - Chupa Chups Flavour
Zebra Sarasa – Chupa Chups Flavour

In the video review, you’ll also see my first scented pen, or at least the first I remember – a Hello Kitty Pen I got in the early or mid-1980s.

Scented Hello Kitty Pen
Scented Hello Kitty Pen

You can watch the video review here.

Or in full screen on YouTube.

More Sarasa Chupa Chups goodness at The Well-Appointed Desk. There are also several other smells, including from the Mister Donut series reviewed at The Pen Addict.

Zebra DelGuard

I realise that the blog post about the force needed for the sliding sleeve of different mechanical pencils was not very popular, so please bear with me for a similar blog post, before I get back to more traditional blog posts.

In January this year I bought the Zebra DelGuard mechanical pencil in 0.5mm. You might have come across it on Lexikaliker, where it was mentioned in October 2014. I bought mine from Japan, through Amazon Marketplace where it was sold as the Delgado pencil, instead of DelGuard, based on the Katakana spelling of the pencil’s Japanese name.

I paid £5, but I noticed that it is now available for £4.26, including free delivery.

Two different mechanisms

This mechanical pencil’s ‘specialty’ are two different mechanisms that help prevent the leads from breaking.

If there is too much axial pen force, i.e. pressure is applied to the lead towards the centre of the pen, the lead will retract, i.e. it is cushioned, somehow similar to the Faber-Castell TK_Fine Vario L.

If there is too much normal pen force, i.e. pressure is applied to the side of the lead, a protective guard will extend to protect the lead from breaking. This guard can obviously only extend a certain amount, so it is possible to break an excessively long lead, more about this later.

Axial vs Normal Pen Force
Axial vs Normal Pen Force (open in new Tab for details)

Not working as advertised?

The packaging states that ‘If you advance lead more than 4 times breakage is possible‘. I wonder whether they either explained it wrong or whether I got a dodgy DelGuard, because using my normal writing angle on my DelGuard the lead will also break if the lead has been advanced 4 times. More on the clicks later. Maybe the text should read  ‘If you advance lead 4 or more times’? Maybe other DelGuard users can comment on this.

Comparison with another mechanical pencil

I compared the pressure that will cause the lead to break to another mechanical pencil. I chose the Kuru Toga, previously mentioned here, thinking that both are from Japan, so there is a higher probability of the leads they come with being similar in terms of softness and strength [1]Comparing the breakage point to a pencil with much harder or softer lead would be less exciting.. Both mechanical pencils were tested with the leads they came with using an angle of 45°.

What force is needed to break a lead of what length.
What force is needed to break a lead of what length.

The axis at the bottom shows the lead length in millimetres, with the number of clicks marked as well. You will probably have to enlarge this image to see it well (right click and open in new tab/window). The axis on the left shows the force needed, in Newton, to break the lead.

To put things in context: The highest force needed for moving sliding sleeves was 1 N, but even to break a very long lead you need more than 2 N.

Personally I don’t extend the lead more than 0.5 mm or 1 mm, so I don’t really have problems with lead breakage anyway, but that didn’t prevent me from getting a DelGuard to marvel at the engineering ingenuity that built this pencil.

As you can see, the longer the lead extended on the Kuru Toga (red line) the easier it is to break.

For the DelGuard (blue line) it is virtually impossible to break the lead if it”s extended less than 1.5 mm, because of the guard that will extend. The dotted blue line represents the situation if you count bits of the lead being chipped off as breakage, the solid blue line represents proper breakage.

The warnings that came with the diagram from the Color Eno blog post apply here as well [2]Here’s a copy and paste: I have neither the training, nor experience, nor the equipment to take these measurements properly, so you better take these measurements with a pinch of salt, or even … Continue reading.

Leads and millimetres

One click on the DelGuard will advance the lead by ~0.52 mm, less than what you get with the Kuru Toga, where one click will advance the lead by ~ 0.57 mm and certainly less than what you got with many pencils reviewed at Dave’s Mechanical Pencils. The break safe ‘zone’ for the extended lead is therefore everything between 0 mm and 1.6 mm. I usually don’t extend the lead more than 1 mm, so the lead is quite safe, but other people might use their pencils in different ways.


Please have a look at this little video I made to see the DelGuard in action (Watch in YouTube for higher resolution).


If you like this blog post you might also like the blog post about the Noris colour wear and tear.


You can find a review of the DelGuard at The Pen Addict and at That One Pen.

You can read more about Axial and Normal Pen Force in this paper. 


1 Comparing the breakage point to a pencil with much harder or softer lead would be less exciting.
2 Here’s a copy and paste: I have neither the training, nor experience, nor the equipment to take these measurements properly, so you better take these measurements with a pinch of salt, or even better with a whole lorryload full of salt.