The Uniball Signo RT Gel mini Hack
Wednesday, May 31, 2006 In my creating a custom Moleskine planner post, I mentioned a Uniball Signo RT Gel 0.38mm pen, for both creating the planner and writing agenda and task items.
Initially I'd purchased a 4-pack of Pilot G2 mini 0.5mm pens for pocket-ability, but found the ink bled a bit too much through the thin Moleskine pages, so I picked up a 4 pack of Uniball Signo RT Gel 0.38mm pens. The thinner 0.38mm gel pens work well with Moleskine paper because the line is thin and quick drying.
This weekend I was looking at the Uniball Signo and G2 Mini, when I wondered if I could hack the Uniball 0.38mm refill to work in a G2 mini pen body. When I took the two pens apart, I realized it could be done, with a flick of a utility knife to trim the Signo's cartridge down to size.
In the spirit of DIY, I gave it a try. The G2 mini to Uniball Signo mini conversion worked so well, I've decided to to share the easy conversion process with other Uniball Signo fans out there, complete with photos:

1. Here you can see how the G2 mini and Uniballl Signo compare side by side. The G2 mini is about 4.5 inches long, compared to 5.5 inches for the Uniball Signo. For pocket-ability, that reduction of an inch means quite a bit — making the G2 mini well-suited for pockets.

2. Next, I opened up the two pens to compare the length of the cartridges, and as you can see, the Uniball Signo is about 1 inch longer, but has room for trimming. I've noticed that new Uniball Signo cartridges have ink at or above the location you need to cut them down without creating a mess. The easiest way to remedy this is by drawing with the cartridge until the ink level drops enough that a slice is reasonable.

3. Using a utility knife , x-acto knife or other sharp instrument, trim the Uniball cartridge down to the same length as the G2 mini cartridge as shown in the photo above (see the dotted line). I've that the Uniball Signo cartridge uses a much thicker outer wall compared to the G2 mini, so the G2 may actually have close to the same volume of ink even though it looks like less.

4. Here you see the nicely sliced Uniball cartridge, ready for insertion into the G2 mini pen body. If you want to be non-wasteful, you can keep the G2 mini cartridges for backups, or use clear tape to adhere the chunk of Uniball cartridge you've sliced off to the top of the G2 mini cartridge, and use this in a standard G2 pen. The G2 plus clipped cartridge combo doesn't work in empty Uniball Signo pen bodies, because of the G2's nib.

5. Use your new Uniball Signo RT Gel 0.38mm mini pen, and enjoy! :-)
Related Links:
PlannerHack.com
Moleskinerie by Armand Frasco
Recording Thoughts by Steve Duncan



Reader Comments (16)
I am utterly desperate to find some.
(Vladimir -- try the Uniball gel pens. They lay a very clean line).
If you do cut at the ink line then it might be wise to cap the cartridge somehow... putty maybe. The G2 cartridge has a thinner wall so you can't steal the cap to use on the Uniball cartridge � it's too large.
http://www.shopping.com/xPC-Sanford_Uni_Ball_Signo_Gel_Rt_Retractable_Pen_Micro_038mm_Point_Black_Ink
or
http://officesupplieslane.com/san69034.html
or
http://www.twinsupply.com/proddetail.asp?prod=SAN69034&partner=herb&bn=28776
Never ordered from these guys, but it's at least a lead. :-)
BTW, the code for the black pens is SAN69034, Blue is SAN69035 and red is SAN69036 � those codes turn up all sorts of results on a Google search.
I used to live right near an OfficeMax, and that was where I used to buy them. The (now) local Office Depot doesn't have them. When I hit two OfficeMaxes while traveling, neither carried them.
Rick
Also, I noticed the Pilot refill had a little cap in it. I wonder if the pen's design needs that as a surface to push against? I popped the cap off the Pilot refill and placed it in the Uniball refill after cutting it.
Chrishttp://amateureconblog.blogspot.com/
I think if you draw down the inl level then the cap is not needed -- the Signo cartridge is thicker walled and works fine with the G2 mechanism. I couldn't get that G2 cap to fit the signo cartridge!
I like my pens extra fine and small so I quicklytried your conversion out. It worked great but I don't really like the feel of the G-2 mini. The grip area is too high up for me. But I noticed while I was writing with the Uniball that I really liked its feel. So what I did is convert the full size Uniball down to the G-2 mini size by cutting out a section of the Uniball pen with a hobby saw. It came out great and I like it a lot better than the G-2 mini. One thing I did have to do is glue part of the refill, that I had cut off to fit the G-2 mini, back on to the refill. It was too short to work in the mini uniball. Also, when I was done glueing the pen back together, I noticed that the glue line detracted from the overall aesthetics of the pen. To fix this I took some black 6pt chartpak graphic tape and covered up the seam. It looks pretty good now and I will probably have to try this on some of the other pens I have lying around.Take care,Matt