This table was built from a design intended for a 9 year old age group. 
It was built using 2 x 4 SPF spruce lumber through out with 3/8" threaded rod cut 3  3/4" long bolting the support member's to the legs. The legs are pressure treated lumber (with wood preservatives) for rot resistance over time due to ground moisture at the leg bearing points.

 The photo below shows the underside of the table prior to the braces being installed.

 The photo below shows the assembled table which will now be lightly sanded and stained. End cut preservative will be applied to the bottom cut of each leg.