Material Selection
Picnic table components should be relatively free of cross grains and other deformities. Avoid angular edge grains as they may sliver out in time.

Picnic Table Tipping
Picnic tables can teeter or tip if one side is weighed down more than the other side. The risk of table tipping is reduced by extending the table legs under the table seat as shown in this design.

Two Angle Cuts
This design uses the same angle for the legs and support members. The second angle is for the braces.

Bolted Joints
This design uses bolt connections. Carriage bolts provide structural strength as well as quick and easy assembly without block jigs or guessing where the members go.
Additional reinforcing can be provided by nailing or screwing the members around the bolt connection.

Match angle cuts with the setback

The table and seat support angle are the same as the leg angle.
Having just one angle instead of several angles makes cutting the table components much easier and faster.
This also enhances the overall aesthetics of the table.
The challenge here was to match the table support angle with the leg angle ensuring the table support angle setback meets the leg as shown here.

The angle was found using a trigonometric formula by David Eidsness (software developer).

a = Table support depth (example: a 2 x 4 would be 3.5)
b = Overall height - Table deck thickness - Outer support - Seat height + Seat thickness
c = Seat to table distance
Leg angle = Atan(c/(b-a))

Maximum of two angles for each table

Each picnic table design only uses two angles.
One angle is for the table braces and the other angle is for everything else, namely, the table legs, seat supports and the table top supports.

Brace Design Note:
This diagonal brace design transfers loads through the centre table support to increase table strength by evenly distributing triangular stress moments including shock loads caused from table relocations.
This helps reduce the risk of table end support assemblies coming loose and/or failing completely.
This design also helps prevent the table top members from warping downward over time.
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Design Software Shared Many Years Ago

Note:
My software is perfectly safe but may be blocked or otherwise flagged in error by MS Windows and/or antivirus companies that aren’t familiar with it. Their error is known as a, "False Positive" , explained here.

162000 12-3-19