I have a Plano Compound Bow case (part number 1010635). I needed a better way to hold arrows than the factory provided foam holder.
Step 1: Remove the Old Foam Holder
It came with a foam arrow holder that you glue to the lid (see photo). The arrows tended to fall out and rattled around. The razor arrow points can scratch up your bow, or worse nick your cable.
Step 2: Measure the Lid Inserts
The PLANO case has several extra mounting posts in the lid. See picture with dimensions (in mm) so you can check your case dimensions.
Step 3: Make the Parts and Install
The mounting posts are aligned at an angle so my challenge was 3D printing the bar and clips on a flat plane. Easiest solution is to make snap in pivots for the clip and bar. This way the clips can be positioned in any direction.
Print out two "bars" and 8 clips. The clips will need 3D printer support structure for the pin. Very little structure is needed and I was able to remove the support at the pin by hand.
My first try had the pins even with the print surface trying to eliminate the need for support but didn't like how it came out. I used #6 - 1 " flat countersunk screw. You'll need this since the clips will need to rotate over the mounting screws.
Next project with this is to make a mount for the arrow quiver and containers for the trigger, tips, etc.