I sometimes make boxes for pens or adapt existing boxes for pen storage. I have tried a number of ways to make pen trays but have not found an ideal way of making them.
I currently use dowels stuck to card like this.
IMG_6333 by my0771, on Flickr
IMG_6374_1 by my0771, on Flickr
I have also used an adapted corner moulding which I sanded to almost zero on the lower edge
IMG_0289 by my0771, on Flickr
IMG_3510_1 by my0771, on Flickr
Both of these methods are very labour intensive my current project requires a 16mm gap for the pen and 5mm between. I could mould them from 1mm thick Kydex if I could make a form both male and female.
It is not a huge tray around 230mm x 180mm but I need to make 8 of them the same so if anyone has any ideas how I can make them I would appreciate it.