How to build an Extendable Picnic Table

Part identification & The plan drawings 

Part identification

[a] Table top and seat top boardA piece of sawn, or dressed lumber of greater width than thickness. Usually 19mm (3/4") to 38mm (1 1/2") thick and 75mm (3") or more wide., made from 145 mmAbbreviation for millimeter which is a metric unit of length equal to one thousandth of a meter. 25.4 mm equals one inch. x 45 mm (1 1/2″ x 5 1/2″) stock
[b] Seat braceTo make rigid., made from 145 mm x 45 mm (1 1/2″ x 5 1/2″) stock
[c] Table brace, made from 190 mm x 45 mm (1 1/2″ x 7 1/2″) stock
[d] Table-top support, made from 190 mm x 45 mm (1 1/2″ x 7 1/2″) stock
[e] Seat-top support, made from 145 mm x 45 mm (1 1/2″ x 5 1/2″) stock
[f] Table leg, made from 95 mm x 45 mm (1 1/2″ x 3 1/2″) stock
[g] Seat leg, made from 65 mm x 45 mm (1 1/2″ x 2 1/2″) stock
[h] Extension top, made from 145 mm x 45 mm (1 1/2″ x 5 1/2″) stock
[i] Extension runners, made from 45 mm x 45 mm (1 1/2″ x 1 1/2″) stock

The plan drawings