Everyone has their own ideas and preferred methods of working, here I shall explain the method that I use to make 7mm parallel twist pens, although other sizes, types and styles are available.
Kits for this project vary in price and quality and can be bought from numerous suppliers such as Craft Supplies, John Bodies and Axminster. Each individual pen kit consists of two brass barrels, in this case 53mm X 7mm, a tip, clip, cap, decorative ring, pen refill and the twist mechanism. The choice of wood is down to individual preference, although close-grained woods will turn more easily and give a better finish. Because of the sizes involved any figured or burr wood will be reduced to such a small diameter and thickness that the finished material may be unstable and almost certainly loose the effects which make it so attractive initially. Some of the alternative materials now available, such as ivory, horn, crushed velvet and Corian also make an attractive finish for pens.
Taking your choice of material, cut a blank some 112 mm by 12mm and mark a short pencil line along its length across a point somewhere near its centre. Cut the blank into two equal lengths, the pencil line will mark this cut and act as a reminder of which way around the pen should be assembled to keep the grain running true. Each part should now be drilled along its length with a 7mm twist drill. A pillar drill can be used, or a pen blank vice is available if you can afford it, but I prefer to hold the blank in a chuck, with a Jacobs chuck and the drill bit in the tailstock, and drill them out on the lathe. If the drill is sharp and the swarf is cleared regularly the cut should be clean and true. Many materials tend to tear out at the ends, particularly if too much force is used in the drilling process, so I always drill part way, turn the blank around and complete the drilling from the other end. Never cut to size initially for this reason.
I have heard of people leaving the drilled blanks for a few days and re drilling them in case they move should any stresses released by the drilling have made the wood move slightly, but personally I have never found this to be a problem. If drilling alternative materials use a much slower speed as any friction build up could melt the materials, causing the drilled hole to become enlarged. I have found this to be a particular problem with the Crushed Velvet materials which do appear to be of a softer composition.
Take each of the brass tubes and clean the surface with wire wool or abrasive material to remove any grease or oil etc. in order to give a good keying surface. Put a small amount of glue around one end of the brass tube and using a twisting motion put the tube into the prepared blank. Make sure that the entire surface of the tube is glue. When turned the blank will be reduced in thickness to nothing more than a thin veneer so time and care should be spent on the gluing process as this will strengthen the finished blank. Any areas not coated by the glue could rise slightly, cause the material to lift and probably tear away from the brass tubes. Leave the blank to cure and dry in line with the instructions given for a particular type of glue. Take all reasonable safety precautions when using adhesives, particularly super glues. I always have a de-bonding agent handy!
I use a polyuralene foaming glue that will fill any small tears or gaps on the inside surface of the blank, but any of the modern super glues available will do the job, particularly some of the thicker gap filling types.
Once the glue has dried all four ends should be tidied up and trimmed to length. There are several barrel trimmers available which are very effective. This can be done by hand, or the blanks remounted in a chuck and trimmed on the lathe at a fairly slow speed. Clean any glue from inside the brass tubes and then reduce any excess wood down to the exact length of the tubes from each end. The brass is very soft and will do no harm to the tool and can clearly be seen as the trimming progresses. This will leave a good square end to each blank that will later make the other fittings sit much neater. Alternatively a skew chisel or square ended parting tool can be used to achieve the same effect.
The prepared blanks can be individually turned between centres using several methods, such as a stepped light pull drive and the tailstock. Although there are mandrels available that will take each half of the pen at a time, I prefer to use a good proprietary pen mandrel that will accommodate both blanks at the same time. Various sets of sizing bushes are available for different styles and diameters of pen, but the mandrel is normally purchased with bushes to use with the 7mm twist pen. Mandrels are available in the normal Morse taper fittings found on any lathe headstock, as well as a parallel fitting. Using the bushes as spacers, mount both blanks onto the mandrel with a bush separating the two halves. Bring up the tailstock to support the free end. Check that each blank is the correct way around. The pencil lines marking the cut ends should each be nearest the centre spacer.
And now the easy bit, on a high speed, turn the blanks using a gouge or a skew chisel until they have been reduced in diameter to that of the bushes. I tend to put a very small angle onto the outer end of one of the blanks that I have decided will be contain the tip of the pen, just to reduce the squarness of the end and begin to shape it into the larger diameter of the tip. This can also be done by hand, later once the blank has been removed from the lathe. Some people put a shape into the wood but I prefer to ensure that the blanks are exactly parallel. Take care at this point, using your fingers feel along the length of each blank for the small ridges and dips that can so easily appear and yet so easily be overlooked by the eye. Once the blanks have been finished, removed, and the pen assembled there is very little that can be done. Its usually only at this point that you really notice them!!
Starting at 240 and going down to a much finer abrasive I sand the finished blanks to a finish. Be careful not to create too much heat as the thin veneer of wood could very easily crack or the glue begin to melt and loosen the tubes from the material. The choice of a final finish is entirely personal, but bear in mind that a pen will be constantly handled so something durable is advisable. Friction polish is good, but a melamine lacquer and burnishing cream give a high gloss finish that does not dull when handled.
If using any of the alternative materials I finish with 600 grit abrasive, reducing to 3200, using T Cut as a cutting agent to finish the blank, and a resinous based car polish for that extra gloss.
The separate components of a twist pen are all a tight push fit onto the blank. There are several proprietary presses and arbors available on the market, and a bench vice with soft protection on the jaws could also be used. I like to use a hand held quick release bar clamp with wooden jaws fitted.
Remove the finished blanks from the mandrel and lay them out exactly as they come off. At this point be very careful to match the two ends that had earlier been marked with the pencil line and were each at the centre bush of the mandrel next to each other. This will maintain a good grain match. The components should be fitted in a precise order to avoid one part interfering with the fitting of another.
Push fit the point into the blank with the slight taper previously made on one end until, a good flush fit is achieved. Next fit the twist mechanism into position and again using the clamp, push it into the other end of the blank fitted with the point until it reaches the indent mark. Do not over push this fitting. Fit the ink refill and operate the twist mechanism ensuring that the point of the refill protrudes a suitable length. Adjust the twist mechanism until this has been achieved. Making sure to keep the grain in line fit the clip and cap onto the end of the other blank. Finally fit the decorative ring over the twist mechanism. Push fit the two parts of the blank together and line up the grain. I like to line up the grain when the pen is in its closed position.