A fender washer is a flat washer with a particularly large outer diameter in proportion to its central hole.
Space the holes evenly, then bolt the stringers temporarily with 3/8-inch-diameter carriage bolts, flat washers and nuts.
This eliminates the need for a flat washer.
Square nuts are used along with flat washers in order to avoid damage from its sharp edges and helps to increase the strength of the fastener.
Screws should be No. 8 roundhead wood screws with flat washers.
The initial target was generally a flat washer the size of a silver dollar.
Then install three-eighths-inch-diameter lag screws and flat washers in the holes.
Bolt the posts together, using galvanized bolts with wide, flat washers.
Then install carriage bolts, three-eighths of an inch in diameter, using nuts and flat washers.
