specializes in offering patterned pen blanks that can be used with commercial pen or pencil kits. Such kits are available from several woodworking oriented companies. (Penn State Industries, Craft Supplies USA, Woodcrafters, Rockler, etc.)
The original concept was to leverage the Shapeways website ShapeJS creator feature to allow pen makers to specify their own tube dimensions, patterns, and materials for specfic kits of their own choosing. There are many kits out there but Oliver Krangle doesn't have the time or money to offer pen tubes for all of them. Sadly the ShapeJS mechanism linked to shops is no longer being fully supported (it may return in the future).
In place of the ShapeJS feature Oliver Krangle will be offering one or two pen tube designs for various pen kits as example starting points. A larger variety of example designs will be offered for select pen/pencil kits (Slimline Pro click kits) which can be ported to other pen kits on request, assuming Oliver Krangle has the time to do so.
The pen/pencil kits generally consist of all of the components needed to assemble a pen except for wood or acrylic rectangular blanks that customize the appearance of the finished pen. While wood and acrylics can create beautifully finished pens the process can require machinery such as a drill, lathe, and cutting tools which may not be accessible to all hobbyists. 3D printing opens up new opportunities to create physically patterned tubes that are ready for use with the kits but with little to no machining required.
At minimum you will need a pen press or a similar mechanism to press fit the parts of the pen kits together for final assembly. Other supplies such as sandpaper, glue or epoxy, and finishing laquer may also be useful or required depending on your approach.
A big difference of using pre-patterned blanks is a senstivity to gluing the blanks to the internal brass tubes. It's easy to make a mess of things and get glue on the outside surface of the pen so protecting the tube surfaces with removable tape can be quite beneficial during the gluing step. On the bright side you may not need to use any glue if the tube fit is tight enough and any lathe operations are not required.
Several categories of 3D printed tube designs can be offered:
1) lathe - If you're an experienced pen maker you might appreciate a patterned tube with a slightly oversized outside diameter. This allows the glued together brass core and tube to be be machined for the best fit possible. These blanks are slightly longer than required by up to around 20 thousands of an inch depending on the kit and manufacturing tolerances. They can be trimmed to proper length using barrel trimmer tools designed for pen makers. Alternately the ends can also be sanded down with the careful use of a machine sander or hand sanding on a flat surface. The option of having dual color finished tubes is also possible using lathe tubes. For example a red versatile plastic tube with an engraved pattern will have white highlights where it is machined on a lathe since the dye used to color the tube only slightly penetrates the surface of the tube.
2) ARTG (Almost Ready To Go) - If you don't have access to a lathe you might appreciate a patterned tube having the proper outside diameter, although I tend to go with outside diameters that are just a hair larger than required to try and avoid having them be too narrow. These blanks are also slightly longer than required by up to around 20 thousands of an inch depending on the kit and manufacturing tolerances. They can be trimmed to proper length using barrel trimmer tools designed for pen makers. Alternately the ends can also be sanded down with the careful use of a machine sander or hand sanding on a flat surface.
3) RTG (Ready To Go) - RTG blanks are still considered experimental by Oliver Krangle although they can be offered on a requested basis. RTG blanks may be more appropriate for tubes manufactured in metals such as cast bronze or a full color plastic process where trimming or sanding would be difficult or affect surface colors. In general many ARTG blanks could be considered to be RTG blanks but the pen maker would need to decide for themselves whether the purchased blank is actually ready to go without any trimming or sanding. A finished tube that is too long can prevent the ink roller ball from sticking out far enough from the pen tip. If the tube is too short the ink roller ball can stick out too far.
For additional information consult the penmaker's interest group in the Shapeways forum
Here's a good general overview of how to make a pen. Every pen kit might have slightly different requirements during assembly so always consult the instructions. Remember, 3D printed tubes are meant to replace wood blanks, but the general principles still apply.