This is compatible with NERF and PICATINNY Rails.

Project Description

This is a simple, low-profile 3D printable sight designed to work with a thin transparent plastic insert. Instead of expensive lenses, I used a reused sheet of plastic, cut down to size.

The design securely holds the plastic sheet in place while keeping the sight lightweight and compact. It’s easy to print, requires minimal post-processing, and lets you fine-tune clarity by swapping or trimming the plastic insert as needed.

Notes:

• The diameter of the plastic lens is 30 mm (Take this into account when cutting the square shaped sheet out).
• Uses clear plastic from any clear plastic sheet (cut to fit)
• Any thin plastic sheet can be used if you scale down the tolerances of the lens insert portion accordingly
• The red dot must be glued directly onto the plastic insert
• No adhesives required for the insert itself (depending on print tolerances)
• Designed for quick installation and easy replacement of the plastic insert
• Works well with common filament types (PLA, PETG, etc.)
• Accuracy depends on proper alignment of the red dot. Take your time when gluing for best results.
• Nerf blasters are known to be imprecise, do not expect it to be perfect.

Materials Needed

• 3D printed parts
• Plastic sheet. 28 - 30 mm wide, and 50 mm long.
• Cutting pliers - For detailed cuts
• Scissors - For cutting of the sheet.
• Sandpaper - For rounding off uneven edges of the lens.
• Liquid Glue, Gorilla Glue is recommended, but you can use others.

Print Settings
Layer Height: 0.2mm
Infill: 15%
Supports: Tree - Hybrid, with 0.275 mm top Z distance.
Material: PLA or PETG

Assembly

First, cut out a piece of plastic that is 28 - 30 mm wide, and 50 mm long, and slide it into the lens part.

Make sure you trim the plastic, I used cutting pliers, and then sanded it, if it is rough, you will have a harder time inserting the lens into the sight.

If the plastic is loose in the lens, adjust the Tolerances of the it using a cad software. After you are satisfied with the lens, test it by sliding it into the sight, it should be tight, but still easy to remove. Carefully add a dab of glue on the center of the plastic. Then using needle nose pliers, place the red dot on top of the glue. 
 

Wait 2 - 4 hours until the lens has dried. Insert the lens into the sight, here should eb enough friction to keep it in place.
 

Slide the sight onto the rail of your nerf gun, and then fasten it in place with the rail lock.

Congratulations, enjoy your new red dot sight!