If you can find a disk sander, that would be the tool to both true up the pen blanks and to ease the corners.
Although, I'd see if a woodworking friend could cut and plane you some lengths of consistent size from a larger board. Really simple and, much safer!
To ease the corners you'll need a jig. I hope I can explain it because I can't use any of the CAD programs well enough to picture it.
Sizes mentioned can vary to suit your disk sander and table. My disks are 12", so I'm using measurments appropriate for that size disk.
Start with a piece of 1/2 ply, 8"X8" should be sufficient. Cut two lengths of solid wood approx. 6" long and miter one end of each @ 45 degrees. Place them on the ply so that the miters align with one edge of the ply at the center, with a small gap between them. Attach them to the ply. Now, a die should fit and the corner should protrude a bit through the gap and beyond the edge of the ply.
You are going to advance the jig and die into the disk.
Now for consistency.
You'll need a stop.
Clamp a 1/2X1 stick to the disk sander's table. This is your stop. Ply would be OK. Placement will be trial and error. You'll also glue two like pieces on the bottom of the ply. Align one with the edge of the ply and a bit in from the edge....enough so that it will contact the piece clamped to the table when you've achieved your desired amount of easing. The other piece you'll glue to the underside of the ply, towards the back, to stabilize the jig on the table.
In use, you'd place the die in the ""V" and push it against the "V" to advance the jig to the disk until it contacts the stop.
You'll end up with sharp beveled corners on the die. Easing off the sharpness would be a job for a foam sanding block. A few strokes with the block should do the trick.
Hope this helps.
So this is too weird..... I did a search this morning for squaring wood with a disc sander, and BOOM http://content.penturners.org/librar...discsander.pdf
THIS IS FANTASTIC. My disc sander is just a hand held model, but I am hopeful I can find a table mounted version for around $100 or less?
Now my only issue would be how to get the tapered edges on each die, AND have them be consistant from side to side, die to die.