Steps:1. Measure inside of window frame using tape measure. Assemble one corner of your frame and measure it as well (figure A). Subtract twice that measurement to allow for the frame.
2. Mark measurements on all frame pieces and cut on miter saw (figure B). Be sure to wear safety glasses when cutting. Cut frame material with a miter saw at a 90-degree angle.
3. File rough edges on cut ends. Test-fit frame and assemble if the fit is satisfactory (figure C).
4. Since the window's handle will have to be accessed through the screen, Harrison suggested building in a small door in the screen. Measure equal distances from the center of the handle.
5. Cut frame pieces to create inset screen. Assemble components and test fit on main frame and around handle (figure D).
6. Set frame on level surface and cover large opening with screen. Secure the screen by pressing it into the grooves using the spline tool (figure E). Cut away excess screening using a utility knife.
7. Build a spacer to fit the small screen using half-inch furring strips (figure F). Cut 45-degree angles on the ends and join strips using wood glue and nails. Pre-drill pilot holes for the nails and set below the surface using a nail set.
8. Clamp the spacer and the small frame in the workbench and add small hinges at the top of the frame (figure G).
9. Attach the small door to the larger screen. Run a bead of construction adhesive along the perimeter of the wooden spacer (figure H).
10. Mount small door to larger frame by pre-drilling pilot holes and attaching with screws. Cut away the portion of the larger screen inside the spacer (figure I).
11. Secure screen to window using frame clips. Test the little door to see if you can access the handle and open and close the window (figure J).