I've had these v6.8 files the computer for over 2 months and someone just reminded me about them. I havent had time to cast these yet, so be warned! but this modules might offer an improvement over the others.

CHANGES: A) The ribs are slimmer, so the handle piece can be smaller + so less shrinkage B) There are slots on the corner pieces, so no holes need to be drilled. C) There are follower patterns which fit under the corner pieces (using 3mm pins to locate), these follower wedges mean you dont have to 'dig out' the corners when sand casting now. eg place side on bench with follower wedges under the corners. fill the drag with sand. Flip it over and now instead of having to dig out the sand to reveal the corners.... just remove the plastic follower wedges!!! (you need one follower wedge per corner)

but yeah it's untested so far. i've just not had the time. but i might as well release these incase someone wants to be brave! please let me know how it goes :)

If you want some that have been tested and work... try version 6.7 here: version 6.7: https://www.thingiverse.com/thing:4033453