Sea Chest Beckets are the handles found on the sailors sea chest, and are considered by many to be the ultimate show of the skills of the Marline Spike Sailor.
Practically all of the knowledge of ropework and knots the Sailor had accumulated could go into the making of a single pair of Beckets.

A Sailor would spend many hours of his spare time aboard ship making a pair of fancy Chest Beckets to adorn his sea chest.
His chest was his one private place where he could keep his few treasured possessions.

Fixings.
Traditionally chest beckets where fitted to the sea chest using hand made copper rivets.
I attach the chest beckets with 2 inch solid brass screws and solid brass cup washers, the doorknocker beckets I attach with 3 inch solid brass screws and solid brass cup washers.
In most cases there are two screws to each cleat.
I use this method of fixing as it gives a clean finish to the cleats, also making them removable.
If you wish to attach the Beckets with hand made copper rivets, you can drill through the wooden cleat, using the pilot holes already drilled as a guide.
you may have to find some copper rod to fashion your own copper rivets.