Bluebird House/Nest Box

Update : [Aug. 5, 2024] Based on a suggestion in the comments, I modified the design of the Front piece to add some “perch slots” to the outside of the front - this should make it easier for the bluebirds to grip the otherwise slippery plain front.

Note : [April 4, 2024] This bluebird nest box is based on dimensions from other published designs in wood, but has not yet been tested. I plan to use the nest box this year to see if it attracts bluebirds, and otherwise holds up to outdoor use.  I will update this description with the results in a year or so.

Bluebird houses (nesting boxes) require specific dimensions and design features to attract bluebirds and protect their nests. Some of these features include a specific size of access hole, and internal “ladder”, and a “no perch” requirement. Here is a useful link on bluebirds and their nest boxes :

https://www.audubon.org/news/how-build-bluebird-nest-box

My design is based on the guidelines in the above link, with some minor differences to allow for 3D printing.

Note that this print requires additional hardware; typically :

• MountingBlock :
  • M4x16 SHCS with washers and hex nuts (qty 4 each)
  • M6x35 hex head bolt (to mount to post)
• Thumbscrew and Lock :
  • M4x30 SHCS and hex nut

There are five parts to the nesting box, plus one additional part for mounting to a pole. The estimated costs and printing times for these parts are as follows (these will vary of course, based on the type of printer you have and how much you pay for filament). Costs below are based on PETG at 28$US/Kg :

Assembly and Use

See photos for additional information.

Additional parts required (stainless steel hardware is recommended):

• M4x16 SHCS with washers and hex nuts (qty 4 each)
• Thumb screw - M4x20 SHCS (see Related Prints below) and hex nut (qty 1 each)
• M6x35 hex head machine screw and nut for large post mount (see note following)

Note : The post mount hardware needed depends of course upon the type of post you use. I used a 7ft (2133mm) U-Post.

Begin the assembly by adding the four hex nuts to the hexagonal recesses in the MountBlock - four on the back side and two on the front side. I recommend using a SHCS and washer inserted into the hex nut through the hole opposite the hexagonal recess, and then tightening the screw to pull the hex nut into the socket (the hex nuts will be a tight fit). Be sure to insert the M6 hex head mounting bolt into the baclk of the MountBlock before attaching to the Body.

With the hex nuts and M6 bolt in place, fasten the MountBlock to the back of the Body using SHCS screws (with washers). 

Prior to assembly of the remaining pieces, I recommend lightly sanding (I used 180 grit) the side grooves for the Front piece, as well as the sides of the Front piece that slot into the grooves. I also used a bit of paste wax on the sides of the Front so that the Front piece slides smoothly in the grooves. Set the Front piece aside for now.

Next, slide the Roof piece onto the body - back to front - as far as it will go. Do not force it past the stops.

Prepare the Lock piece by inserting a M4 hex nut into the hexagonal recess using the same method as before. Slide the Lock into the dovetail recess in the Bottom. Note that the Lock piece has “crush ribs” on the dovetail section, in order to make it a tight fit into the dovetail slot.

Slide the Bottom piece onto the dovetails on the bottom of the Body from the back; line up the  the slot opening on the Bottom with the slot opening on the Body.

Finally, slide the Front piece up into the grooves in the body, being sure to push it all the way up into the recess in the underside of the Roof. Note that the Front piece has “grip slots” on both the front and back sides - the long slots should be on the inside. Secure the Front in place with an M4 thumbscrew.

Related Prints

To construct an M4x20 thumb screw, see this print :

https://www.printables.com/model/732566-thumb-screw-knob-for-socket-head-screw-inch-681014

For the mounting block and bracket, see this print :

https://www.printables.com/model/832491-mounting-block-and-bracket-for-u-post-and-round-po

Print Instructions

Print in PETG using the 3mf files provided, otherwise, for all parts except the Lock :

• 0.2mm layer height
• 3 perimeters
• 20% grid infill

For the Lock piece :

• 0.2mm layer height
• 5 perimeters
• 50% grid infill

CAD

The OnShape 3D CAD files for this are here :

https://cad.onshape.com/documents/d5358816a6ed989435ba1d4f/w/8cb2c939c7a5a1ac6ce46640/e/91f3e5920c31d69bbea26681?renderMode=0&uiState=660f05c112d8994f53b03d82