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JOEL Joel's Blog

The Engineering of a Pencil Point

04/13/2022

 From the top: Sharped with a stationary sharpener - long point; long point ; short point
From the top: Sharped with a stationary sharpener - long point; long point ; short point

I spend a lot of time writing and sketching. And while thinking about that, I got to thinking about pencils -- or, more accurately, pencil points. Now a pencil is only as good as its point, and while it's certainly satisfying to sharpen a pencil with a pocketknife, most people I know, myself included, use a pencil sharpener of one kind or another. I have plenty of urgent work to address, but instead I found myself wondering about the angle of a point, since the angle of the point actually makes a difference. Electric and cranked pencil sharpeners almost always make what we call a "long point." Cheap sharpeners, usually found in schools, are usually twisted by hand to shave a point, and typically produce a short point. But hand shaving long point sharpeners do exist. Blackwing, which arguably makes the best pencils in the world, makes long point pencil sharpeners that shave a long point. The engineer in me wants to know why long point is better.

(Before I get started: yes, I know mechanical pencils exist. But I have a heavy hand and the lead keep breaking on me, so I don't like them.)

What is the practical difference in use between long and short point pencil sharpeners? If you have both long and short point pencils, both perfectly pointed, and draw a line with equal force, in theory they will produce the same line density (darkness) and start wearing down at the same rate. However, because the pencils are sharpened at different angles, the long point version will wear down to a narrower line while the short point will wear down to a wider line.

But the short point will be stronger, and if the user has a heavy hand, that short point will resist breakage better. Long point pencils will "keep sharp" longer, but you have to use a lighter touch. This is why artists prefer a long point and children's pencil sharpeners are always short point.
 From left to right: Blackwing long point sharpener; Regular short point sharpener; Boston Champion cranked sharpener that dates from the year one
From left to right: Blackwing long point sharpener; Regular short point sharpener; Boston Champion cranked sharpener that dates from the year one

The next thing to consider is the sharpening. The whole point of a pencil is that the lead is fairly brittle and the wood body of the pencil prevents the lead from breaking. You can shave off the surrounding wood pretty easily, but if you aren't careful, the lead will break at the point. You have to peel away some of the wood, and then point the lead (actually graphite-clay) core. Now the actual composition of the lead core determines its color, density, how fast the point will wear and how easy it is to break a tip. Generally speaking, a given manufacturer's harder leads won't write as dark or dense as their softer leads, but harder points stay sharp longer. But the longer the exposed point of the lead is, the more fragile it is, and the easier it is to break when while sharpening. There are two ways around this problem: the first is use a power sander and sand off the wood and lead at the same time. This is done is just about every shop I have ever been in. The second way is to use a power sharpener, or even a hand cranked one. These sharpeners go round and round quickly and take off very little material on each pass and don't stress the material, and they produce a long point.
Hand sharpeners that shave the wood off are the problem. Humans can rotate a pencil by hand only so fast, and if the sharpener takes off too much lead too fast, the point will break. On the other hand, removing too little wood means it will take a long time to sharpen the pencil. With a short point sharpener, you solve some of the problem because the amount of lead is shorter. A steeper angle has less exposure on a shorter and stronger exposed lead, which will be harder to break. This is why most hand pencil sharpeners sold are short point.

The other way of sorting this out is to do what the Blackwing sharpener does with their two step sharpener (actually a rebranded German sharpener). In the first hole, you quickly shave off the wood exposing the lead. The second hole has a much finer feed and you point the lead. This approach works well.

I have a tendency to use the Blackwing sharpener more than my crank sharpener because I don't have to turn around on my desk to my bookcase where the cranked sharpener is kept. And to be fair, after serving generations of my family for about 80 years or so, it's kind of dull.

I honestly can't tell you that having a long point pencil sharpener will change your life. I wish it was that easy. Wouldn't it be great if I could say to someone, you know things are tough here - there's Covid, there's war, there's a lot of stuff going on, everyone is under a lot of stress, but get a long point pencil sharpener and your problems will be solved. That would be so nice. But the fact that a long point sharpener doesn't lead instantly to world peace doesn't take away from the fact it's a pretty good sharpener and I like a long point for less frequent sharpening. Also I have to learn how to press less hard (which should lead to writing faster anyway).
You can find out more about Blackwing pencils and the sharpener here.

Incidentally Blackwing also makes an aluminum single-stage sharpener that is beautiful to look at. Nobody in the shop could make it work when it first came out we broke too many leads. So we don't stock it. Other people love it, I have no idea why. We also stock a wonderful little notebook they issued in honor of Woody Guthrie. We love them.
The cranked sharpener also holds your pencil. How cool is that!
The cranked sharpener also holds your pencil. How cool is that!


N. B. Most shops I know use pencils a lot - sometime mechanical pencils, but more commonly a regular pencil. If this is what you do in your shop, do everyone a favor and get an electric long point pencil sharpener and plug it in somewhere prominent. The Blackwing sharpener is the next best thing. Your work will subtly improve.

N. B. We stock Blackwing pencils. They are produce a dense black line. My personal favorite is the "firm" classic 602. It's a great compromise because smooth dark writing and a fairly long lasting point. For precise layout on stock I use a knife.

The internal mechanism of the cranked sharpener is an amazing pair of tapered spiral cutters. Awesome!
The internal mechanism of the cranked sharpener is an amazing pair of tapered spiral cutters. Awesome!
Join the conversation
04/13/2022 Jay Simmons
Have had one of the cranked Boston sharpeners since the early 1960’s. The big advantage was due to it holding and feeding the pencil you could hold the sharpener down and did not need to have it anchored down. Another advantage was the spring mechanism fed the pencil straight and evenly, avoiding breaking the tip of the lead. In our plaster walls home per my Father you did not screw into the wall for anything less than an original Rembrandt.
I have the Boston in my shop and yes it is getting dull, probably when these were made you could purchase replacement cutters. Since the relative diameters of the cutters are important I am not sure that surface honing (yes, they are easily removeable) Any suggestions?
In grade school, since we were not well trained in tool maintenance, we had pencil and tablet inspections by Mrs. Lees. If the shaved portion of the wood was dirty or the point was broken, you were marched up to the sharpener. No worry, half the class was already there.
You are correct. Blackwings are the best of the best. Been sketching with them for years.
04/13/2022 Kerry Benton
My favorite sharpener is essentially a modern analog of the old Boston you've got.. It's made by Mitsubishi (model KH-20) and consistently makes perfect long points pretty fast and has a tidy little drawer for the shavings.

I tend to handle sharpening as a batch job... I keep a rice-filled jar of a dozen or two sharp pencils handy in the shop and at my desk, and when one gets too dull for me, put it back in tip down and grab a new one... when I run out of sharp ones, I sharpen them all at once. The sharpener is quick enough that it only takes about a minute or two to do them all and I don't have to break flow for sharpening so often.
04/13/2022 Ed Furlong
I have the same Boston Champion Sharpener in my shop. Works well and haven't yet had a dullness problem but will now be on the lookout after reading Jay's comment. I would think surface honing might result in the pencil going in a bit more but if the honing is light and even, the tapered cutters should still work, since they cross at the inmost point. Just a guess, though.
04/13/2022 Louis Lampe
I use a Sandpaper Pad bought online from Cheap Joes Art Stuff.
Picture a wooden paint stirrer with strips of sandpaper glued on. About $2 at any art/drafting supply store. But I also use a marking knife when I want a knife wall.
04/13/2022 Ed Swartz
You've answered so many questions I've always wondered about (and others that I regrettably have not been thinking about!) So... you could be on your way to solving world peace....who knows!

For many years I thought I could "fix" my sharpening problem(s) by adjusting the angle of the pencil (micro bevels anyone?) but that made for short fattys or far too delicate skinnys.

Will be by to buy...Thanks again for the wonderful pondering and musings
04/13/2022 Dave Polaschek
The X-Acto Ranger 1031 wall-mount pencil sharpener is another modern analog of the old-school hand-cranked pencil sharpeners. I have two of them (one in the office, and one in the shop) that I bought along with a gross of Dixon-Ticonderoga #2s. As Kerry does, I batch-sharpen a dozen at a time. Which can lead to days when I have six different pencils out, all of them too short to fit in a compass, but still long enough that “it’s still good!”
04/13/2022 Roy Tuller
Great article! I too am a pencil lover and have the various sharpeners as mentioned above. Just wanted to add to the mix the Cabinet Makers HØVEL pencil plane which is also fun to use.
04/13/2022 dcpritch
I recently found and restored an ancient (1920s) Climax 3 pencil sharpener that provides the longest, sharpest point I have ever encountered on a pencil. If you can find one, I recommend it highly!
04/13/2022 Eric Kuehne
If you're serious about this you should look into manual drafting equipment. I spent my first 10 years as a design engineer with a drafting table. If you want to see people who take their pencils seriously that's might be worth looking into. I believe I still have my old sharpener some place. I keep my old drafting templates in my shop and they get use occasionally although I've been a CAD guy since the mid 80's.
04/13/2022 Brian Moran
I love wood pencils… plain, basic, essential. I still use the same Boston crank sharpener in my shop my dad gave my probably 50 years ago. I laughed out loud when I read about “sanding” pencils. Our 8th grade shop teacher, Mr O’Brien, showed us how to sharpen a fine point on a belt sander. We thought that was the greatest shop trick ever… at the time. I haven’t thought about that for years. I might have to pull out a new 220 grit belt and a box of Ticonderogas and go to town! Thanks Joel!
04/14/2022 Bruce
Interesting post. To Joel and other pencil aficionados I highly recommend you read Henry Petroski's "THE PENCIL: A History of Design and Circumstance" or at least the book review in the LA Times: www.latimes.com/archives/la-xpm-1990-03-04-bk-2455-story.html Petroski is a Civil Engineering and History of Technology professor who has written a dozen excellent books, and has an astonishing list of professional honors.
04/14/2022 harry bryan
Hello,
I have been a fan of Boston sharpeners for years. They have been bought by X-Acto who has cheapened the construction. However, they have made one design change that (in my opinion) makes their model KS the best sharpener on the market.
The helix on the old Bostons (and indeed on most rotary sharpeners) turned in such a way that the cutting action was from the point, up the slope, to the full size of the pencil. Any woodworker has learned that wood does not like to be cut this way. X-Acto has reversed the helix so that the cutting action is toward the point. The cutting action and the resulting point are incredibly smooth, even with coloured pencils. The user must learn to hold the pencil with the fingers against the sharpener as the pencil tends to be drawn into the machine. Usuall two turns are all that is required for needle-like point.
04/19/2022 Jesse Griggs
I'll have to try some blackwing pencils. I've been partial to Ticonderogas, and hate cheap pencils. for sharpening i recommend David Reese's method: https://youtu.be/VkSmaFAuaH4
05/04/2022 Charles Stratton
Hello,
I've been a fan and customer of Tools for Working Wood for many years. I own two of the KUM long point sharpeners which I purchased several years apart at the local art supply house. Unfortunately the most recent one does not work as well as the original. I will be purchasing the new Blackwing version soon as my original KUM is showing it's age and beginning to fall apart.
On the subject of wooden pencils I'd like to mention a book "The Pencil" by Henry Petroski. It is a brilliant work on the history of pencils and an amazingly entertaining read. The pencil you hold today is a major technical triumph.
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