The very cool thing about this mandrel is the expansion nut design. It's main feature is when the nut is tightened, the opposite end of the mandrel expands in two directions, keeping the blank perfectly centered relative to the mandrel. Alternatively, common pin-chuck designs lock the blank in place by rolling a loose pin up against one inside surface of the blank's brass tube, often causing an out-of-round turning, where one side of the finished blank's wall is thinner than the opposite side.

To make a closed end Baron pen, you'll need a blank that is at least 3" long. Drill a 25/64" hole down the center of the blank, exactly 2 7/8" deep.

And here's a special tip...the lower barrel hole is drilled deeper than normal so you've got clearance for the rollerball innards, resulting in the stock brass tube not bottoming out in the hole. In fact, the stock brass tube is almost an inch shorter than the hole's required depth. The problem is that when you go to press fit the ring and threaded end-piece into the finished lower barrel opening, the glue may give way and the brass will work it's way further down the hole, resulting in nothing to press fit into. My solution is to custom cut brass tubes to the exactly length of the hole's depth. That way the brass tube bottoms out at the bottom of the hole and will always be in the proper position for the press fit operation. Here's a link to longer 10mm brass tubes that can be purchased if you choose to adopt this alternative approach...gluing long tubes in the deep hole.

(Click on each photo below to view a larger image)

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 Here you can see the prepared lower barrel blank and AS's mandrel.

Slide the mandrel into the prepared blank

Make sure the mandrel is all the way in, with the bushing face flush up against the blank's end.

I'm using two box wrenches in this example to tighten the end-nut just enough so the blank is "locked" in position and will not spin around the mandrel shaft.

Next, mount the mandrel's exposed shaft in a drill or scroll chuck and tighten the chuck's jaws down snuggly against the mandrel shaft.

Here you can see that the mandrel has been mounted in a # 2 MT drill chuck so that about 1/4" of clearance between the end of the blank and the chuck is exposed...you'll need this 1/4" space to get your cutting tools in position for the finish cuts. Also note that the tailstock has been brought up to the opposite end of the blank, adding support for the piece while turning.

The blank has been turned into a cylinder, about 1/16" proud of the mandrel's bushing. In this example, I've left the blank extra long...about 4". Note that the hole inside the blank must be 2 7/8" deep to allow space for the roller ball's innards.

Using a sharp skew or parting tool, mark a ring on the blank that is at least 3" to the right of the headstock end of the blank's end. This mark indicates where the end of the finished pen will be and will help calibrate the shape and design of your finished blank.

 I like beads...using a thin parting tool, make the first of two cuts, on the left side of the headstock end of the turning.

 Here you can see the first cut that has been made at about a 45 degree angle.

Now using the point of a skew or thin parting tool, make the bead's second (right-side) cut.

Now I'll be using a 1/2" round nosed scraper to make some decorative cove cuts in the blank. 

Here I'm using a skew to make decorative cuts in the lower barrel's end. 

The thin parting tool is used to make a final end cut, separating the lower barrel form waste wood.

And here, the thin parting tool is used to clean up the end-cut.

While the piece is still on the lathe, sand as you normally would. I'm sanding with 180, 320 and 400 grit papers.

After sanding, apply a coat of Sanding Sealer with a brush or paper towel. Be sure to wipe off the excess sealer before it dries to avoid a clumpy looking surface.

Remove the mandrel from the chuck...

I'm using the mandrel's exposed shaft as a handle, buffing the piece with Tripoli and White Diamond compounds, using the Beall system.

Next, apply a coat of R-wax, wait about 30 seconds and buff the piece out on a third clean buffing wheel.

Then wait about 15 minutes, apply a second coat of R-wax and repeat the final buffing process. BTW, these's just enough time between these two R-wax applications to turn another pen, if you have a second mandrel.

This photo shows all of the hardware included with a Baron pen kit. The four parts shown at the bottom of this photo will not be used and may be discarded or saved as spares.

Put a drop or two of medium thick CA down the center of the finished lower barrel, then drop in the tension spring. Let the CA dry thoroughly before going further in the assembly process.

Finally, assemble the pen as you normally would.

And here is the finished Rollerball Baron in Tulipwood.

The adjustable closed-end mandrel is available exclusively through Arizona Silhouette