"Roughing it."
An efficient method for roughing square wood pen blanks on a metalworking lathe.
-Allen Keehall-
Goal: To efficiently round then drill a square pen blank on a lathe.  This maximizes the amount of useable wood and reduces limitations on a blank's size and geometry imperfections.  You'll get extra blanks and won't need a drill press or fixture to drill for the tube.

Background: Over a period of making a half-dozen pens, I realized that the amount of wood being shaved-off wasn't earth friendly.  The reason why is because the standard way of roughing a blank requires first drilling the blank for the tube.  The drilling process on a square blank has the disadvantage of severe misalignment either in work-holding, blank imperfections, or an axis being warped.  You also need to cut the blank into top and bottom halves, since the bit usually isn't long enough for the full length of a blank.  I find it all rather tedious.

So this is just the way I approached the problem, by eliminating the drill press and end sanding or the counter bore tool.  And by the way,
pressing the pen by using the lathe's tailstock is extremely precise and simple.  No pen-press required, just some scrap blocking.

Method: First I create two perpendicular planes that are as straight as possible. 
Look closely at the blank and you'll see the "straight plane" hash marks (^). Then I  pencil a line down the sides as close to a centroid of mass.  This is easier than it sounds.  A caliper helps find thin spots and a flat block and compass useful for marking warps.

Then you connect these "imaginary" planes on the ends of the blank as you would going corner to corner to find the end centers.  Use a spring-loaded center punch or carefully use your scribe.

Place a pin center in the chuck and slide a rubber bumper over this center.  Let it protrude and LIGHTLY tighten the chuck.  Then align the blank's centers with the pin center on the chuck and the tail-stock's live-center.  With easy pressure, extend the ram and push the blank against the sliding pin center and
bumper.  Neatly align the compressed bumper to reduce wobble.  Tighten the chuck firmly.

With practice you'll master the technique.  Otherwise you can set your centers deeply, remove the blank, then insert the bumper and go from there.  I find the first method easier and with some
chuck-key dynamics you can get the hang of it after a few blanks.

I use an off-the-shelf C2 carbide bit for roughing, but depending on the species (softer woods) you may need something with more rake.  At this point you'll need to use your skill and experience.  I take the blank down to within 0.030" or 0.050" of where I start profiling (depending on curves).  I sand with a 220 grit before chucking.

Then I pull the blank from the centers, place it in the chuck
(easy with the chuck key pressure so as not to dent soft species), and lightly face each end while keeping my center marks intact for drill pilots.

Deviations
  • Drill through each side to depth, then part; or
  • Part, then drill each half; or
  • Drill as deep as possible, part, then finish drilling.
I slightly recess my tubing when epoxying.  After curing I face the blanks and barely graze the tubing.  I'm never messy with epoxy so I don't need a pilot/clean-out bit.  You can always roll a wax-paper tube and place it flush in the brass tube before gluing.  It's simple. 

Conclusion:  This is much easier than it all sounds.  You'll find that the level of precision allows for a tighter fit of your tubing (for thick CA users).  When you place the blanks on the mandrel they'll never have more than a 0.005" to 0.010" offset and be ready to go.  No drill press, no special vises or fixtures, and no pen presses required for final assembly.  But it does require a small metalworking lathe, which typically runs about $150 more than a decent small woodworking lathe.  So the money trade-off isn't a factor, it's the space savings.

You can potentially save workspace (one machine), and stretch your supply of exotic wood scraps with narrower blanks.  I also end up with precise wood rings.  Sometimes I part with a Japanese flush saw and face them.  Then glue the precision rings on longer blanks altering species for end-detailing or stack for composite blanks.

-11/15/2007-
Afzelia Burl Wood Blank
 What I dream of is an art of balance.  -Henri Matisse-
Afzelia Burl Wood Blank
Completed Round Blank
Pin Center and Bumper
Rubber Lathe Dog
Roughing Completed
Profiled and Finished
Gokii Pen
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Copyright 2005-2016, Al Keehall-Labs