A variable slit for use in a spectrometer or other optical setup. 3d printed parts Single Edge Razor Blades (2x) 2mm diameter metal rods cut to lengths (tolerance for cut length is very forgiving like+-5 mm): 144 mm (2x) 90 mm (2x) 52 mm (4x) 15 mm (4 X) M3 bolts 10 mm (4x) 0.4 x 5x 30 Compression Springs (7x) M5 bolt (1x) at least 50 mm M5 nut (2x) Standard Single Edge Razor Blades (2x) Super Glue (1x)

Assembly: Glue two 15 mm rods into the divots razor block mounts. Insert the razors into the notch. The razors can be clamped with m3 bolts but they actually fit snugly so there is not need. With a spring between them thread the the two 90 mm rods through the holes of each razor block mount such that the razors are facing one another. Set razor block mount assembly aside.

Thread a 50 mm M5 bolt through a nut and inset it through the middle hexagonal hole. Add another nut on the other side and tighten deez nuts until they are holding the bolt pretty tight.

Insert the four 80 mm rods into the 45 degree hoes in the the sliding_45degree_push_bar. Optionally add glue to holes to hold these in place. Thread the 144 mm rod through the long axis holes of the sliding_45degree_push bar. Add 4 springs to the 144 mm rods on each side of the sliding_45degree_push_bar. Mount the sliding_45degree_push_bar to the base by inserting the rods into the hole/notch. Mount the razor block mount assembly to the base likewise by inserting the rods into the hole/notch Demonstrate the razor closing slit action. If your satisfied with your slit control then optionally glue the rods in the notches. Finally put the M5 bolt on the bolt. Fin.