Crafting an Acadia TruStone Pen

When I tell someone that I made a pen, exactly what do I mean?  Over 90% of creating a pen has to do with producing the body of the pen. This is where most of the time, effort, and experience is involved. The pen I'm crafting below is the Acadia. This is a medium-sized pen that takes a Parker-style refill. The pen blank for this pen is Azurite-Malachite Tru-stone (the colored block in the picture below). This is a man-made material consisting of 85% natural stone that has been pulverized to a powder then mixed with pigments and acrylic resin, The result is a material that looks and feels like stone, but can be turned on a lathe with typically available turning tools.

Pen components
The core of the pen are the two brass tubes seen below the Tru-stone. These go inside the Tru-stone and are sized to accept the various mechanical and trim components. Above the Tru-stone from left to right are the nib, centerband, transmission, finial holder, clip, and top finial. The trim pieces for this pen are electro-plated with chromium, one of the hardest pen platings available. The transmission converts the twisting motion of the pen upper half to an in-out motion that extends and retracts the refill.

(click on any picture for a larger version)

The first step is to cut out two pieces from the blank, each slightly longer than the brass tube that's going to be placed inside. While not apparent above, the brass tube for the lower part of the pen is slightly longer than the upper pen tube. I use my bandsaw to cut the Tru-stone. This material is pretty rough on blades, so I don't use my new saw blade for this.

I then mount each Tru-stone block in the chuck on my lathe so I can drill a hole through the middle of the block. A Jacob's chuck mounted in the tailstock holds the drill bit.  The drill bit remains stationary while the block rotates.

These pictures show my Jet 1642-EVS2 lathe, which is a full size lathe that can turn large bowls and pretty much anything I want. If you just want to turn pens and smaller items, you can purchase a much smaller midi or mini lathe. They take up less room and cost a lot less. I would highly recommend you get one with variable speed. I use this feature all the time on mine and find it indispensable. 

I use a drill diameter a few thousandths of an inch larger than the brass tube so that the tube can slide easily into the hole. If you drill slowly and frequently empty the cuttings from the hole, it's not a problem drilling the Tru-stone.

Drilled blanks
Here are the drilled Tru-stone blocks. The brass tubes can now be epoxied into the holes.

I first rough up the outside of the tubes with sandpaper to get better adhesion and plug the ends of the tubes with dental wax to prevent any epoxy from getting into the tubes. It's critical that you get full epoxy coating between the tube and the block. I coat both the inside of the hole as well as the outside of the brass tube with epoxy. The tubes are inserted so that a small amount of Tru-stone protrudes beyond each end of the tube. I let the epoxy harden overnight.  Cut-up cereal boxes make great mixing cards for the epoxy.

I next sand the ends of the blocks on my belt sander.

Yes, that is an alligator on top of my drill press. A souvenir of our 1963 family vacation to Florida, pre-Disney. What 9 year old wouldn't want a stuffed alligator?

Sanding close-up
Here's a better view of the sanding operation. It's key that the block is held square to the sanding belt, because you want the sanded surface perpendicular to the hole.

You continue sanding, a little at a time, until you reach the brass tube. Be careful not to sand away any of the brass tube.

sanded end
Here is a close-up of the sanded end. The dental wax is still plugging the brass tube.

ready to turn
I also sand away the corners of the blocks to make them easier to turn.  Then I remove the dental wax plugs and clean out the inside of the brass tubes using an appropriate sized brass wire brush. If any epoxy does adhere to the inside of the tube ends, this can be removed using a Vargus deburring tool.

Mounted on lathe
For my initial turning, I use bushings at each end of the block. These are specially designed for making pens. Part of the bushing is sized to the brass tube and slips inside. The part of the bushing outside is sized to the desired diameter that you want to turn the block down to. I mount these bushings on my lathe using a cone drive center (left) and revolving cone center in the tailstock (right). 

Rough turning
Here is what the piece looks like after rough turning. I find that a skew works well for more rapid material removal.  The Tru-stone will quickly dull the tool though. A carbide-tip scraper (shown) will do a great job in shaping and the carbide can stand up to the Tru-stone.

Once I get close to the final dimensions, I remove the bushings and place the brass tube directly between the cone centers. This is called "between-center turning" and I find it to be more accurate in keeping the turning precisely aligned around the central axis of the brass tube. Now it's a matter of doing the final shaping and dimensioning of the piece, stopping frequently to check measurements with the calipers.  I measure the trim pieces used for this particular pen and custom fit the body to precisely fit the trim pieces. You'd be surprised at how much variability there can be in a supposedly uniform part.

Before removing the piece, I do initial sanding with 320 and 400 grit sandpaper (Norton 3X is the best sandpaper - worth the extra money)

true ends
Next I mount my home-made squaring block. This is a piece of hard maple mounted onto a faceplate. I trued-up the face of this piece and  stuck on a velcro backing pad. I can then easily place hook-and-loop sandpaper onto the block. Using a Jacobs chuck in the tailstock, I place a center punch that is just small enough to fit inside the brass tube. Now I slide my Tru-stone body piece with brass tube onto the center punch. This holds the piece exactly parallel with the turning axis. When I slide the Tru-stone piece up against the sandpaper, it accurately squares the end of the piece. This makes for a precise fit with the trim components.

Ready to polish
Here are the body pieces all ready to polish. Note the visible sanding marks from the 400 grit sandpaper.

The piece goes back on the lathe between centers for wet sanding with Micro-mesh pads. I go from 1800 to 3600 pads (equivalent to 1350 grit sandpaper), which starts bringing a gloss to the surface.

I next polish the body pieces using my buffer. I order my buffing supplies from Caswell Plating. Their 6" Canton Flannel wheels work very nicely. I use their Formax 6163 and 6165 polishing compounds on my two wheels. I'm able to get a high gloss, glass-like finish from the buffer.

polished comparison
Here is a comparison of the two body pieces. Guess which one has been micro-meshed and buffed?

end view
Now both pieces have been polished. Here is an end view of the body piece that abuts the nib. Notice how the Tru-stone is about 1 mm thick at this point. This is why it's critical that the Tru-stone be turned around the precise center axis of the brass tube. Any variation at all will result in varying thickness around the brass tube and a sloppy fit.

pen press
Pen assembly is next. I use my drill press as a pen press. The various components are pressure fitted into the ends of the brass tubes. I use a little Loctite to ensure that these fitting stay tight.  I always debur and wire brush the the brass tubes before assembly to smooth the assembly process.

After assembly, I'll put on a light coat of Renaissance wax and buff with a soft cloth. The wax helps prevent fingerprints.

finished pen
And here is the completed pen.

While the concepts of making such a pen are fairly simple, there is a lot of equipment, technical know-how, and skill required to get a pen that is perfect. I make my pens one at a time and derive my enjoyment by making each one as perfect as I can get it.