After you have all of your pieces cut now you can start to assemble the first stage of your pen.  This is the most critical and tedious part of your pen, as any  part that is not perfectly straight and lined up perfect will show in the final results.

You have to make a right hand and a left set of three pieces.  Start by laying the first piece flat on your bench,  glue the second piece on top at a precise 90 degrees, glue the third piece at a 90 degree angle on the right side of the second piece. Do the same with the left hand set.

  After the right set and the left set has dried you can glue them together to make the first layer of your pen.  It takes six pieces for every layer that you need, so depending on how long the pen tube is the number of layers will be different for every different length pen tube.  The  last photo shows the two maple sets setting on an already glued walnut layer.  The next photo shows what a perfect fit would look like when all sides are at a perfect 90 degrees, straight and flush with the parts they are glued to.

You have to end up with a perfect fit or zero clearance on all sides.  The last photo is what you do not want to see, notice the gap between one of the  sections.

This picture shows a small gap on the lower left section.  If this was left like this there will be an ugly space on your finished product, or a space that will fill with glue and that will look just as ugly.  This is non adjustable, there is no fix for this problem on this layer except make a new layer and try to get it more precise so when you glue the sections together all sides are tight.  

This is where the difficulty of making this style pen comes to play, there are so many glue joints and different surface planes that all have to match perfectly. 

After you have tried to make several layers you may think that some joints are ok or close enough,  that is not acceptable as your final pen when turned on the lathe will have defects and will fail as a pen to sell.  This is where a lot of people give up as it just takes too much time and patience.  Check back as I will continue with many more steps to making one of these.