Slot handle sliding cover with router template

Slot handle cover to keep dust and light out of the storage containers, drawers etc. The default version uses 4 M2.5x10mm countersunk head screws, but this can be changed in OpenSCAD Customizer.

Suggested workflow:

1) Measure the thickness of the stock for slot handle and the screw dimensions for the cover guides. Enter these parameters (stock_thickness, screw_thread_diameter, screw_head_bottom_diameter, screw_head_top_diameter, screw_head_height) into the customizer.
2) Render (F6) and export the model as .stl file (F7).
3) Print only the frame and the cover. Unless they have suitable size change slot_width and/or slot_length parameters and return to step #2.
4) Print remaining parts and use screws to install the router template to the stock.
5) Cut the slot with template (or flush trim) router bit, remove the template and sand the slot.
6) Use the same screws and remaining screw holes to install the cover and its guides.

Troubleshooting:

If the cover doesn't return to the closed state under the influence of gravity - increase cover weight by printing it with 100% infill or increasing cover_thickness parameter (increasing cover_clearance up to 1.0 may also help).
If the frame doesn't fit into the slot - increase or decrease the frame_clearance parameter.