Building 50birds Nestboxes

 
The 14 degree roof angle used in 50birds Birdhouse Plans corresponds to what framers and roofers often refer to as a "3:12 pitch"  -  3 inches or feet of rise to 12 inches or feet of horizontal length.   A 3:12 pitch then is the same as 1:4 pitch, one inch of rise to 4 inches horizontal distance.   Knowing the 1:4 relationship between rise and length, one can easily determine the rise on any side panel using the floor dimensions. 

The height of the back edge of a side panel of 4" width (equal to floor widths), is exactly one inch greater in height than the front edge (one quarter inch rise for each inch of width).  A side panel of 5" width differs from front to back by 1 1/4", one of 6" width rises 1 1/2" front to back, and so forth.   
 

The inside height of the front panel is identical to the front edge height of a side panel.  Power saws can then be set at 14 degree angles (roughly, it's not critical) and cuts made following a pencil marked line on the long edge (inside), of the front panel (front panel has the entrance hole).  

Purple Martins

Once a woodworker fabricates a few nestboxes based on this convention, the dimensions of any one of 25 models can be arrived at knowing only the floor size and inside front ceiling height, which are coded into the nestbox model numbers. Find free printable woodworking plans for these and more 50birds birdhouses in the Models Index.

   a   floor dimensions
   b   inside front floor to ceiling
   c   inside floor to top of hole
   d   hole dia. ex:  112 = 1 1/2"
                         1916 = 1 9/16"

Finer dimensions such as plus 13/16" on the opposite side (front height of the front panel), do not have to be measured.  If the saw angle is reasonably close to 14 degrees, and if the inside height is measured, marked and cut reasonably close, the finished panel will serve its purpose.  

Tolerance on a bird house which needs ventilation is not very critical.  Mistakes, crooked cuts, gaps, etc. may be a good thing.   Where panels are square, rectangular and cut at right angles (90 degrees), where precision is easiest to accomplish, good fit and fastening make for a sturdy box and a secure home.

Dimensions such as 31/64" are not meant to indicate the need for low tolerance.  They are just precise computer calculated dimensions and arrived at when the opposite side of a panel, 5/8" or 3/4" thick, is cut at a 14 degree angle.  Use them as dimensions to check, before cutting, after cut lines are drawn, or just ignore them.  The measured dimension is on the opposite side where the cut line is drawn.   Neither is critical.  In fact, it might be best, depending on climate and sun exposure to cut the front panel 1/2" or 3/4" short to provide extra ventilation. 

For simplicity, move to the next larger increment.   For example, 31/64" can be adjusted to 32/64", which is the same as 1/2".   Similarly, 13/16" can be thought of as between 3/4" and 7/8", plenty precise wood working for bird houses.

You may wish to cut larger portions out of the floor and side panel corners than plans specify or drill holes for more ventilation in warmer climates.

Hinges are suggested for easy access.  Other methods for attaching roofs are just as good or better.   However, most nest boxes are mounted out of reach for most people.  Bird house mounting, monitoring and maintenance on ladders is an awkward chore that requires three hands.  The convenience of hinges increases safety.

Materials are not critical.  Cedar is nice.  It is often rough cut, or simulated, which is good for grip, and it endures.  When fresh, it has a repelling effect on some insect pests.  Pine will do. 

3/4" stock is the most common.  5/8" stock where called for can be supplied with fencing material from most lumber yards (5/8" stock is used on the smaller nestboxes because 3/4" stock makes them look odd). 

Bone piles from new fences or home construction sites are good sources for the small sizes usually called for.   You shouldn't have to pay for any if you keep your eyes peeled.

Hardwoods are difficult to work with unless fine joinery is used.  It's more work and not necessary.    The wood layers of plywood will peel eventually as moisture will degrade a glue's adherence qualities.   Plywood may be the best choice where large panels are required for example: in a Barn Owl box or one of the larger nestboxes for Ducks, Barred Owl and Pileated Woodpecker.  If you use plywood, paint the edges.     Resources