[Xer0]

for a project, a ballpen laser engraving machine, i need a rotateable holder which holdts the pen in the axis. a i use a laser and no milling tool, it doesnt have to be robust, just precise and easy to build and adjust. any ideas here?

[koaDave]

What kind of tools do you have access to? Do you have a chuck or something on your A axis? I have drilled a hole in the center of a small wooden dowell that is maybe 1/64th small of the diameter of what you want to hold. Then saw across the end of the hole 3 or 4 times so the fingers can flex a bit. Trial and error will tell you how many cuts to make, and how deep they should be to grip your pens. How you attach it to the A axis depends on what the mechanism looks like. A pen should slide into the hole and be kept secure and concentric while you laser it. You may or may not need a tailstock depending on the shape of the pen.

Here's a drawing (I hope). Hope this helps.

Dave