Home-brew Jetstream Plotter Pens

After a relative lack of success in making cheap plotter pens, I managed to score a trove of old pens on eBay. Some of these were dry, and I tried to resuscitate them. A few came back to life, but I ended up with a handful of very dead pen shells.

A dry plotter pen, possibly Alvin

I think the pens were made or sold by Alvin, as there were several empty Alvin trays in the batch I got on eBay. In taking one apart, I thought that a pen refill might just slide inside. Lo and behold, but didn’t the pen nerd’s fave gel pen du jour refill just slide in with enough of an interference fit that it wouldn’t easily slide back out.

Taking the dry pens apart isn’t too easy:

  1. Pull the black tip straight out with pliers; it has a long fibre plug which goes into the ink reservoir. Discard the tip.
  2. While it’s really hard to see, the other end of the pen body has a push-on plug. Gently working around it with a sharp knife can open it up a bit.
  3. Once you’re inside the pen, pull the dry fibre ink reservoir out with tweezers and discard it.

Converting the pen body to use a Jetstream refill needs some tools:

  1. Drill a hole in the plug at the end of the pen body just large enough to allow the end of the refill to pass through. It helps if this is mostly centred to keep the pen point centred; this is important for accurate plots.
  2. Cut a piece of tubing just wide enough to slip over the pen refill, but not quite narrow enough to fit through the hole you just drilled. I used some unshrunk heatshrink tubing for this. It needs to be just long enough to push against the plug when the pen tip is at the right length. This should help stop the refill getting hammered back into the body by your plotter.
  3. Before you assemble the pen, I find it useful to cut a couple of flats in the sides of the plug so you can more easily change the refill. You don’t have to do this, though.
  4. Assemble the pen:
    1. Push the Jetstream refill into the pen body, and adjust it so it sticks out about 6 mm clear of the plastic collar near the nib.
    2. Put the tubing over the other end of the refill, and push the plug over the top, clicking it into place.
Three pens in place on my DXY-1300

To get best results, you’ll have to slow your plot speed down quite a bit. At standard speeds, you get a ¼ mm interrupted line which looks like this:

Jetstream at full speed
Jetstream at full speed

Close up, the lines are really faint

A hint that I should run them slower was at the start of each line, where the line would start very thick, then taper off as the ink supply ran low:

acceleration blobs
acceleration blobs

Run at 120 mm/s, the results where a bit darker, but still blobby at the start of lines:

120 mm/s
120 mm/s

Slowing down to 60 mm/s produced slightly better results:

60 mm/s
60 mm/s

But sharpest of all was at the crawling speed 30 mm/s:

30 mm/s
30 mm/s

Some pronounced blobs at the starts of lines still. Here’s the full page at 600 dpi, squished into a very lossy PDF: jetstream_plotter-slow

The blobs could be due to this, though:

grode on pen tip
grode on pen tip

It seems that a mix of paper fibres and coagulated ink builds up on the tip. Occasional cleaning seems to be a good idea. It also seems to help to draw a quick scratch line before anything important so the ink will be flowing properly.

Just to sign off, here’s one of the pens in action:

Making cheap HP plotter pens + yet another HP-GL viewer

If you’re running an old plotter, getting pens can be a worry. While there are some companies that might still make them (Graphic Controls/DIA-Nielsen, for one) they are expensive and limited in range. They’re also felt-tip, which means they’ll dry out if not carefully re-capped.

While eBay might supply all things (like these Roland DG plotter pens I scored a couple of days back; fine, black, new old-stock, or these German plotter pens), I also found this:

$_3It’s described as “11.5*28MM cutting plotter vinyl cutter pen holder 50mm for Roland holder Pcut”. I bought two, and eventually the slow boat from China came …


The one on the left is an unmodified pen holder. Well, it’s really a ballpoint-refill holder, as it comes with a (random colour of blue) refill.  To modify these to fit into an HP desktop plotter, you will need to:

  1. Cut ~10 mm from the end of the holder. A Dremel + cutting disk is a satisfying way of doing this. The gap between the knurled bit and  the thread seems to be a decent place. Clean up the sharp edges
  2. As the knurled lock ring will stop the pen engaging in the carriage (my HP-7470A does a lovely little hesitant try… nope; try… nope; try… give up sequence), you’ll have to do without it. Find another way of jamming the threads of the threaded collar in the right place. I used electrical tape, and it’s held so far. Wiser users will use different colours of electrical tape for different pens, ahem …
  3. Stick the pen refill in and tighten down the collet lightly with pliers. ¡¡¡ Do not try to pull the refill out while it is in the collet !!! (The ballpoint insert will likely pop out, and viscous ink will start to blort out everywhere. Ask me how I know!)
  4. Snip the end of the refill flush with the end of the pen holder using diagonal cutters. Best to do this directly over a rubbish bin, as pen ink is nasty. Dab off excess ink from the end of the refill, and clean your cutters, too.
  5. The base of the threaded collar should be around 29 mm from the pen tip, otherwise nothing will plot (if it’s too short) or you’ll poke holes in the paper (if too long). This measurement doesn’t seem to be extremely critical: my Roland pens have it at 28.5 mm, the DIA-Nielsen pens are 28.9 mm. One of my homebrew pens is working at 30½ mm, but then, my basic plotter has no force control, so it may be more forgiving than more elegant beasts.

modified holders and cut/not-so-cut refills

My modified pens look like the above.

The dollar store is a good source of cheap ballpoint pens. I managed to snag 8 retractable red pens for $1.25, and 4 black pens for $1.

one of the donor red pens, plus the disassembled pen holder

(These retractable pens more often than not eject the whole internals across the room when you retract ’em.)

It’s probably a good idea to scribble with the pens a bit before and after modifying them, as they take a while to flow freely. They plot very lightly; the black ink looks more like a faint pencil line.

Double-plotted nested bézier curves
Double-plotted nested bézier curves

If you look close up, not merely are the lines very faint, but something else important shows up:

double-plotted detail, showing off-centre effects (actual size 17 × 17 mm)
double-plotted detail, showing off-centre effects (actual size 17 × 17 mm)

The lines — which should be a constant(ish) distance apart, if the paper has stayed in registration — are showing a varying distance from each other. It looks like the pen points are a little off-centre, so when the pen is swapped out, it gets turned to a slightly different position. This would really only matter for precise work, and I find the effect interesting.

As for the HP-GL viewer? GhostPDL, by the makers of Ghostscript. You’ll have to build it from source, and its documentation isn’t quite where one might want it to be, but it implements a full HP PCL6  / HP-GL/2 interpreter than can output bitmaps, PostScript or PDF. The SVG graphic below was made using the tools/plot2pdf.sh script to convert HP-GL to PDF, then I used ghostscript to convert that to SVG. Nifty!

weave.pltAs a bonus, GhostPDL comes with one of the prettiest plotter fonts ever:

kind of defeats the purpose

The highlighted text says “Staedtler Textsurfer Gel highlighter”, but you can’t read it because the highlighter made the ink fade.

rebooting the handwriting

My handwriting is atrocious. It’s scrawly, uneven, with malformed letters (r never recovered from Miss MacFarlane’s ligatures, t usually left unstroked) meandering up and down the line. It’s got blotchy, affected borrowings, too: tailed and stroked 1s and 7s in the European style, and a d that was least seen in a partial differential: 𝛿. In short, a style all my own, wanted by none.

I’d prefer to have my handwriting legible to others, and even by me. I don’t want my notebooks to look like a spider’s hauled its bedraggled carapace out of the inkwell onto the page. Unfortunately, cursive is right out to learn. I can’t read it, in any style. In fact, I find the German Sütterlin to be as logical to learn, as I can’t read that either, but at least it looks badass.

The style I’m trying is pre-cursive. Yes, it’s meant as a transition from printing to cursive, but I like its simple clean italic lines. I imagine I’ll join it up a deal more when I’m writing quickly. The hardest part for me is sticking to the line and stopping my writing wandering off up the page.

We’ll see how this goes …

(and thanks to I want to write right! | Ask MetaFilter for the suggestions.)

The Sharpie Liquid Pencil – massive letdown

In Primary Six to about First Year [so about 1979 to 1981], the thing to have was a Papermate Replay, the first real* erasable ballpoint. Despite their waxy purplish-blue ink (which had a strong piney aroma) it was the one thing all the cool kids had. The Replay erasers were gritty and smudgy, and left black crumbs on the page. I remember the gummy click of the ball on the paper, and the rising fug of Replay ink from thirty desks. When it eventually dried, Replay ink could stick pages lightly together, a bit like paste-up wax.

With the Liquid Pencil, Sharpie probably hopes to repeat the (at least initial) success of the Replay. The technology feels similar — slightly less sticky, and the smell of the ink is different, but there’s still an unusual high note to it. The ink looks curiously as if it’s been photocopied and is of an uneven weight, just like the Replay used to be. Leaning on a freshly-written page from the Liquid Pencil smudges the ink on your hand and partially erases the text — just like the old Papermate Replay.

While the Replay really didn’t like regular erasers, the Liquid Pencil is better with them. If the LP were a real pencil, a heavy trace would conduct:

███ Liquid Pencil: ∞Ω  ███ Faber-Castell 9000 HB: 400kΩ

It doesn’t, so it’s no pencil.

I’m pretty sure the Sharpie Liquid Pencil is just the naff old Replay, repackaged for a new generation. After all, Newell Rubbermaid owns both the Sharpie and Papermate brands. I bet the old news stories about Replays being used for cheque-fraud will resurface. Even writing this has given me the old Replay ink smell headache — déjà pew!
* there were the chemically erasable kind available before, which had a yellowish felt tip on one end that bleached the ink and prevented you writing over it.

Unscrewing the barrel revealed the familiar old Papermate Replay refill. I think we’ve been had.

Update: a bunch of reviews. The ones that actually tried it came to pretty much the same conclusion:


Vinegar’s remarkable ability to clean up spilled ink from a plain wood table is matched only by Waterman Encre Havane’s near-praeternatural ability to get everywhere.

in and around the van

Spent a pleasant, if damp, day scooting around Vancouver and environs with Dave. After a quick tour of Granville Island, we headed off to the Museum of Anthropology at the University of British Columbia. We then had lunch at Fuel, which is extremely good.

We had to work off lunch somehow, so we hiked around Lynn Canyon Park, which includes the nifty and shoogly Lynn Canyon Suspension Bridge. Back at Dave & Leanne’s place, we decided on dinner and a movie, but I had to bail on the movie ‘cos my cold was getting bad.

Vancouver is so green. I like it.

The Apples in Stereo – Lee’s Palace, Toronto – 20 February 2007

In haste: The Apples in Stereo – Lee’s Palace, Toronto – 20 February 2007
(now updated to include better MP3s)

  1. (intro)
  2. Go
  3. Please
  4. Can You Feel It?
  5. The Rainbow
  6. Energy
  7. Strawberryfire
  8. Radiation
  9. Do You Understand?
  10. Open Eyes
  11. I Can’t Believe
  12. (apples in stereo mini-theme)
  13. Skyway
  14. (mini theme/tuning)
  15. Motorcar
  16. Tin Pan Alley
  17. Sun Is Out
  18. Same Old Drag
  19. (theme interlude)
  20. What’s the #?
  21. Ruby
  22. (encore intro)
  23. Play Tough
  24. Baroque

the reluctant rockstar of climate change

I was at Nicholas Stern‘s presentation to the Economic Club of Toronto today (as was Bob, David, Deb, Glenn, Paul, and about 490 others). He was very low-key; not sure if his dry sense of humour got the response he expected. The CBC covered it.


Portpatrick, with the Gimp faux lomo effect
Portpatrick, taken with a Fujifilm MX-1200 pretending to be a lomo

For probably no better reason beyond babbittry, I’ve always half-wanted a lomo. Half-wanted, that is, because of my previous experience with “Russian” photo gear (I’ve had a Lomo TLR, a Fed rangefinder, and a Pentacon six) and its legendary quality control. I’m also so done with film.
A while back, Donncha wrote about a  GIMP Lomo Plugin. While it looked handy, the link to the code is now dead. You can find what I think is the same one here: http://flelay.free.fr/pool/lomo2.scm (or a local copy here if that link dies: lomo2.scm). Just pop it in your .gimp-2.2/scripts/ directory, and it’ll appear as a filter. The original author‘s comment on Donncha’s blog contains good settings: Vignetting softness=1, Contrast=30, Saturation=30, Double Vignetting=TRUE.

I knew there was a reason I retrieved my old 1.3 megapixel Fujifilm MX-1200 from my parents’ house. And that reason is fauxlomo!

All the printers I’ve ever owned …

bird you can see: hp print test

  • An ancient (even in 1985) Centronics serial dot-matrix printer that we never got working with the CPC464. The print head was driven along a rack, and when it hit the right margin, an idler gear was wedged in place, forcing the carriage to return. Crude, noisy but effective.
  • Amstrad DMP-2000. Plasticky but remarkably good 9-pin printer. Had an open-loop ribbon that we used to re-ink with thick oily endorsing ink until the ribbons wore through.
  • NEC Pinwriter P20. A potentially lovely 24-pin printer ruined by a design flaw. Print head pins would get caught in the ribbon, and snap off. It didn’t help that the dealer that sold it to me wouldn’t refund my money, and required gentle persuasion from a lawyer to do so.
  • Kodak-Diconix 300 inkjet printer. I got this to review for Amiga Computing, and the dealer never wanted it back. It used HP ThinkJet print gear which used tiny cartridges that sucked ink like no tomorrow; you could hear the droplets hit the page.
  • HP DeskJet 500. I got this for my MSc thesis. Approximately the shape of Torness nuclear power station (and only slightly smaller), last I heard it was still running.
  • Canon BJ 200. A little mono inkjet printer that ran to 360dpi, or 720 if you had all the time in the world and an unlimited ink budget.
  • Epson Stylus Colour. My first colour printer. It definitely couldn’t print photos very well.
  • HP LaserJet II. Big, heavy, slow, and crackling with ozone, this was retired from Glasgow University. Made the lights dim when it started to print. Came with a clone PostScript cartridge that turned it into the world’s second-slowest PS printer. We did all our Canadian visa paperwork on it.
  • Epson Stylus C80. This one could print photos tolerably well, but the cartridges dried out quickly, runing the quality and making it expensive to run.
  • Okidata OL-410e PS. The world’s slowest PostScript printer. Sold by someone on tortech who should’ve known better (and bought by someone who also should’ve known better), this printer jams on every sheet fed into it due to a damaged paper path. Unusually, it uses an LED imaging system instead of laser xerography, and has a weird open-hopper toner system that makes transporting a part-used print cartridge a hazard.
  • HP LaserJet 4M Plus. With its duplexer and extra paper tray it’s huge and heavy, but it still produces crisp pages after nearly 1,000,000 page impressions. I actually have two of these; one was bought for $99 refurbished, and the other (which doesn’t print nearly so well) was got on eBay for $45, including duplexer and 500-sheet tray. Combining the two (and judiciously adding a bunch of RAM) has given me a monster network printer which lets you know it’s running by dimming the lights from here to Etobicoke.
  • IBM Wheelwriter typewriter/ daisywheel printer. I’ve only ever produced a couple of pages on this, but this is the ultimate letter-quality printer. It also sounds like someone slowly machine-gunning the neighbourhood, so mostly lives under wraps.
  • HP PhotoSmart C5180. It’s a network photo printer/scanner that I bought yesterday. Really does print indistinguishably from photos, and prints direct from memory cards. When first installed, makes an amusing array of howls, boinks, squeals, beeps and sproings as it primes the print heads.

penticentenary (if that’s the right word)

I’ve been driving for 20 years. Seems a long time since I took that Mini Metro (which stank of Insignia aftershave – the instructor used it to clean the glass) from the BSM depot in
Pollokshields and puttered around the south side.

No speeding tickets, no parking tickets, and only one insurance claim. The insurers must be making a fortune from me.

computer joy

Uhoh, there’s a huge Canada Computers opening just up the road; next to this sign, in fact. I’m glad I no longer commute past it; the temptation would be too strong.

new greenery

Finatics were having their opening sale (yes, it seems that they were open before, but not officially) so I got a whole buncha plants to replace the rather gnawed/algaed ones I had.

The algae eaters were not pleased to have the tank delved about in, no sirree.