How to build a Bench Swing Support Frame
Step 4. Add a brace
Fasten a diagonal brace to the horizontal brace of the "A" frame as shown in fig.12.
Secure with a couple of 100mm (4") galvanized nails and a nail-on plate.
Next make up the second "A" frame BUT WITHOUT ADDING THE DIAGONAL BRACE, as that brace will be added when the (almost) complete frame is standing upright.
Step 5. Fix the beam to an "A" frame
Tilt an "A" frame against the beam in a sort of a 3-sided pyramid shape so that the beam, "A" frame top and diagonal brace all align.
Ensure that the top end of the beam is overhanging the "A" frame by 100mm (4") and that the beam is at right angles (90°) to the "A" frame.
Refer to the plan if necessary.
Then, fix the beam to the "A" frame with galvanized nail-on plates. Refer to the 'Fastening detail' page, and fig.13 on this page.