Adjustable optical slit with a screw and foil-blade seats

Change slit width during a simple optical experiment. Two straight-cut opaque sheets of your own form the edges; one is fixed and the other sits in a guided slider. The screw pushes the slider closed; after backing off the screw, pull the slider back by hand to open it. Intended slit travel is 0 to 5 mm, with no scale or guaranteed precision. Frame, removable top guide, slider and screw are four separate parts. Two M3 screws and nuts retain the guide. Cut the fixed sheet 10 mm wide and window height + 13 mm tall; cut the moving sheet 12 mm wide and window height + 9 mm minus twice the guide clearance tall. The moving edge projects 2 mm beyond its holder; small tape tabs outside the window retain the sheets. Install the slider before the top guide. Use with low-power LED light, not lasers or hot lamps. Adjustable values: Clear optical-window height: 12–24 mm; Spacing between the outer mounting-hole pairs: 40–60 mm; Thickness of your opaque sheets: 0.1–0.5 mm; Adjustment-screw pitch: 1.25–2 mm; Guide and thread clearance: 0.2–0.4 mm. Have your own 3D printer? Configure the dimensions, purchase the STL file and download the 3D model to print yourself. Without a printer, have us make the part: choose a material, calculate the price online, then order and pay online. Geometry has been digitally checked. No physical test print has been carried out. The product image is a photorealistic AI visualization of the default dimensions. Mentioned third-party accessories are not included.