Colored pencil holder sized for prismacolor pencils. Other pencils with a diameter of 0.29" should fit. 12 pencils fit in each base piece and two bases are attached with a link, so it can hold as many pencils as you have. Pencils can be stored tip up or down, there is a step in the base to keep the tip from hitting the bottom and breaking when stored tip down.

I used 3mm filament 'rivets' to attach the pieces together, and I think it gave it a nice clean look.
(http://makezine.com/projects/make-34/skill-builder-finishing-and-post-processing-your-3d-printed-objects/) Scroll down to "Using Filament to Make Solid Rivets and Hinges"
Alternatively you could probably use a screw and a nut. I think a 4-40x.75 flat head machine screw from the bottom with a nylock nut on top would work ok.

Both the size of the pencil holes and the end holes are pretty critical for the holder to function properly. I've included a test piece 'base2_test.stl', and would recommend printing a test, checking the fit, and scaling appropriately.
-The holder should grip the pencil tightly enough that it wont fall out, even upside down, but loose enough to not damage the wood of the pencil. There is enough spring in the thin part of the wall to accomplish this.
-I left the end holes on the tight side so they would make a tight fit with the 3mm filament rivet. You may need to clean them up with a drill bit if they are too tight.

I printed with:
PLA
Cura
3mm layers
1.05mm walls (see below)
25% infill
1mm top and bottom

When slicing look at the toolpath for the top thin part of the base, and make sure its not putting small dots of infill in there. Adjusting the wall thickness slightly (+.05mm) will get rid if this.