Ventilated Beehive Entrance Reducer & Mouse Guard

(I was told OBJ files are better than STL so initially I didn't make an STL folder for the MK III but now it is there.)

Latest Update: Introducing the Mark III

****************************************************************************************************************

Mark III Universal Beehive Entrance Guard / Reducer (4-Way)

Now upgraded to Mark III

This is a fully 3D-printable, highly versatile beehive entrance system designed for Nuc, 8-frame, and 10-frame hives. It features a universal mounting entrance and a smart four-way rotatable door that gives you four distinct entrance options in one compact design.

### 4-Way Door Functions:

- Position 1: Fully closed (perfect for transport, wintering, or complete shutdown)

- Position 2: Reduced entrance opening (standard foraging entrance)

- Position 3: Fully open Queen Excluder (full access for workers, excludes the queen)

- Position 4: Reduced Queen Excluder opening (smaller protected entrance with queen exclusion)

Simply rotate the door to switch configurations in seconds — no extra parts needed.

### Key Features & Updates (Mark III):

- Universal Fit: Mounts cleanly on Nuc boxes (no side guards required), 8-frame, and 10-frame hives.

- Symmetric Side Guards (for 8-frame & 10-frame only):

- Print the same side guard model twice — works on either left or right side.

- Integrated foot tabs on both ends for easy screwing into the bottom board.

- Robust & Ventilated: Thick perimeter frame with ventilation holes throughout. Keeps out mice, robbing bees, and debris while maintaining good airflow.

- Secure Mounting: Uses #8 × 3/4" panhead screws.

### Printing Instructions:

- Supports: Not strictly necessary, but recommended for best results on the overhangs of the entrance piece and side guards.

- Top Z distance: 0.25 mm

- Top interface layers: 3

- Top & Bottom Surface Pattern: Concentric (produces the best results and strength for this model)

- Recommended Settings:

0.2 mm layer height, 3–4 walls, 15–25% infill, seam position - back.

### What's Included:

- Main universal entrance

- Four-way door/reducer (one piece with all four functions)

- Symmetric side guard (print ×2 for 8- or 10-frame)

### Quick Installation:

1. Print all required parts.

2. Attach side guards (if using 8- or 10-frame) with two #8 × 3/4" panhead screws per side.

3. Mount the main entrance to the hive.

4. Insert the four-way door to your desired setting.

This Mark III version is the most refined and user-friendly yet. One model truly does it all — perfect for beekeepers running mixed hive sizes or who want maximum flexibility.

****************************************************************************************************************

Previous Updates:

• I've uploaded files for 8 frame hives. You will need #6 x 1/2in Philips flathead screws for these.

• I've added a ventilated door with a small opening (see picture). This is to prevent robbing.

• MK II with Bottom Board Mounting Tabs (see picture).

          Added integrated mounting feet/tabs (with straight screw holes) to the side pieces and main guard.

          This allows you to screw the reducer directly to the bottom board.

          Download MK II if you want bottom-board mounting instead of, or in addition to, the hive box.

          Mounting screws (required for MK II): #8 × 3/4" pan head screws.

          (The holes are straight, not countersunk — flat-head screws will not sit flush.)

• I added dedicated folders for 10 frame and 8 frame hives to avoid confusion.

• I updated the dimensions for the 8 frame files. The total millimeters were a few too long and wouldn't fit on the bottom board, but it should fit now. 

• Added a combo door file. I fused the fully closed door and the partially open door into one combo door. Now it's just one piece, simply take it out and flip it to use either type (see pictures).

Beehive entrance reducer/mouse guard with removeable door and added ventilation holes to allow airflow when the door is fully closed (prevents moisture/condensation buildup in winter while still blocking mice/pests) and great for transportation.

Print tips:

• Supports are not necessary for this model, the geometry prints well without them in most cases. However, I used supports because I was having some overhang sagging issues and wanted the surfaces to be perfectly flat and flush for a clean fit on the hive entrance.

• I printed mine in PLA because I don't mind reprinting after a season or two. PLA holds up decently outdoors for 1–2 years (or longer in shaded/less extreme conditions) before noticeable UV degradation, brittleness, or fading sets in; especially if it's not in constant direct sun. For longer-term outdoor use (multi-year durability with better UV and weather resistance), I recommend PETG or ASA instead.

My recommended PLA print settings:

• Nozzle temperature: 215–220°C

• Bed temperature: 60°C

• Print speed: 125 mm/s

• Wall loops: 3

• Infill: 15–20% (gyroid or cubic works well for strength without wasting filament)

To secure the reducer to the beehive:

• I use zinc-plated #8 x 1/2in Philips flathead screws, three per side piece (left and right) and three for the entrance guard, for a total of nine. This provides even, secure holding without splitting the wood (pre-drill pilot holes if needed). Galvanized or stainless steel screws can be used instead for better long-term rust resistance in wetter climates.

Installation flexibility:

• You only need to screw in the two side pieces (3 screws each). The middle guard (with ventilation holes and sliding door) can simply slide into place between the sides, no screws required for the center piece if that is your preference. This keeps it held firmly while allowing easy removal if desired. Remove the middle guard entirely for a full-width entrance in summer (improves foraging traffic and ventilation during hot weather or strong nectar flows). Re-insert it quickly for winter protection, robbing defense, or mouse guarding. The sides stay put year-round.

For 8-frame Langstroth hives:

• If mounting to the hive box, you might need #6 or #7 flat-head screws, since I scaled it down from original 10 frame model it might be tight. But for the mounting feet/tabs, use #8 × 3/4" pan head.