Cokin P to Z standard 100mm filter adapter frame

Adapter to use Cokin P photo filters in standard 100mm filter holders, like the Haida M10-II (tested) and Cokin Z (not tested).

The Cokin P filters are typically 85mm square and 1.6mm thick. The 100mm filters are 2mm thick, so they fit within the frame. One of my filters was only 83.5mm, so I also added a slightly tighter variant in the 3MF file. 

I tested with PLA an PETG and found that PLA works better, because it is more rigid. 

I went through many iterations trying to avoid using tape on the front, but in the end I found that this approach provides the best rigidity for holders that squeeze the filters, while staying with the 2mm thickness limitation. Alternatively, you can probably glue the filters in the 4 corner holes, but I have not tried that yet, as the tape method works well enough for me and is less permanent.

Onshape model: https://cad.onshape.com/documents/c4d56530277d0ff1e1a3e119/w/ee858133b63d118b509369fa/e/f17bb5053365340511737a61