Lens Cap for SMC Pentax 15mm wide angle

This is a lens cap designed for the legendary SMC Pentax 15mm f/3.5 Ultra-Wide Angle.

Since original metal caps are rare and expensive, and standard "snap-on" caps can easily scratch the finish of the integrated metal flower hood, this model was developed to provide a secure "suction fit" using a soft neoprene lining.

Key Features:

• Precision Suction Fit: Designed with an internal diameter of 82.2mm, perfectly calculated to host a 1mm thick neoprene strip. This creates a soft, scratch-free, yet incredibly firm grip on the 80mm lens hood.
• Integrated Neoprene Recess: The interior features a 14mm wide recessed track. This prevents the adhesive neoprene tape from peeling or shifting when sliding the cap on and off.
• More grip: The exterior boasts a classic diamond pyramid relief. 
• Heavy-Duty Protection: With a 4mm thick bottom and a 2.5mm base wall, this cap offers serious protection for the protruding, bulbous front element of the 15mm lens.

Recommended Print Settings:

• Material: PETG or ASA is highly recommended for UV and heat resistance (especially if the camera sits in a bag in a hot car). PLA may warp over time, but for Sure will work too.
• Layer Height: I printed it in 0.12mm but 0.2mm should work too. Fine layers are better to capture the shape of the grip pyramids.
• Walls/Perimeters: Use at least 4-5 walls. This ensures the textured grip is solid and durable and the whole thing is sturdy enough to do its job.
• Infill: 30% (Gyroid recommended for structural integrity).
• Supports: None required. The design features a 45° outer chamfer and specific geometry that prints cleanly without support structures.

Assembly Instructions:

1. Print the cap with the opening facing up.
2. Apply a strip of self-adhesive neoprene tape (1mm thick, approx. 10-12mm wide) into the internal recess. 
3. Make sure to leave a 1-2 mm gap so the air can escape when pushing it on.
4. Enjoy the satisfying "thump" as the air-tight cap slides onto your lens!