DIY Cross Ion Pen to Stylus Conversion

Cross Ion Pen with origional Pen refilOK, So is an electronics and audio site primarily, but i though I would share with you a half hour hack that converts a Cross Ion Pen into a touch screen stylus for resistive touch screens.

For those who have not seen this pen before, the Cross Ion Pen is a bullet shaped pen approximately 3/4 the size of a standard pen when closed.  It opens by pulling the two halves of the pen apart which both unsheathes the pin nib and elongates the pen to full size.  It’s pretty ingenious though the drawback is that the pen uses non-standard refills which are both expensive and difficult to buy off the shelf.  Some people have resorted to converting other ink refills for use in their Cross Ion.

I bought mine a few years ago and after the pretty miserly ink refill ran out, it was vanquished to the bottom of a toolbox for years.  Recently though I repurposed it for use as a stylus for my Asus T101MT Tablet PC.  The conversion it turns out is a pretty easy job.  I am sure that this little hack could be applied to other pens with similar refill cartridges.

Cross Ion Pen DismantledThe Cross Ion Pen is easy to disassemble, twisting the rubber grip unscrews the pen and it reveals its “oh so expensive” yet small ink refill.

The refill itself is a shorter version of many gel ink refills, made up of a metal nib inserted into a soft plastic ink reservoir.

Donor Stylus Vs Cross Ion Pen Refill

I already had a stylus tip which I had salvaged from a cheapo retractable computer stylus which had a broken mechanism.  If you were looking to do something similar, E-bay has many very cheap potential donors or you can buy.  Look for one of the dual function ball pointy/stylus devices.

Alternatively you can buy stylus refills for popular pens which will probably be suitable.  Even a blunted cocktail stick/toothpick might work, as long as the material is soft enough not to scratch your touchscreen.

The nib of the Cross Ion refill it turns out is  held in place by friction alone, I removed it with a pair of long nose pliers very easily.  A note of caution here, even though the Cross Ion pen had been apparently inkless for many years, some wet ink did leak from the de-tipped refill.  Once the tip was removed I measured it up against the stylus refill that I had salvaged and cut the stylus tip to the correct size.  The diameter of both tips was similar though the stylus tip was slightly wider.

Cross Ion Pen refill with Stylus InsertedI could have attempted to shape the stylus tip, but as the difference between it’s width and that of the outgoing nib were small, I instead force fitted it into the Cross Ion’s old refill cartridge.  The soft plastic of the refill made this easy enough to achieve.

Cross Ion Pen Refill Converted and filed to shapeThe refill cartridge unfortunately bulged slightly to accommodate the increased width of the stylus tip.  When I test fitted this inside the Cross Ion Pen it was apparent that this was enough to foul the pens mechanism.

I then used a micro-file that I had handy to shape the refill where it grips my new stylus tip.  The soft plastic is easy to shape, if you did not have access to a fine file even a strip of reasonably fine sandpaper or a nail file would be perfect for this task.

Cross Ion Pen Stylus TipI filed down the refill test fitting it to the pen every few seconds until the modified refill moved smoothly in and out of the Cross Ions Pen’s mechanism.  Once I was satisfied that it would not jam I reassembled the pen and cleaned up the grot that had attached itself to the outer case during it’s years of tool-box exile.

This turned out to be a really easy hack to accomplish. I’m pretty sure that most ladies handbags would carry sufficient tools to complete the modifications.  I also reckon that the same technique could be applied to many other pen designs.

I was never going to pay the cost of the refills for the Cross Ion Pen, at least now the nifty design will get some decent use.  Bet you have a similar candidate lurking at the back of a drawer.  The Cross Ion design has a nice fat ergonomic grip and it would appear it is very good when drawing on screen.

Note: This works on resistive touch screens only I am afraid.