Carriage bolts have a domed or countersunk head,
and the shaft is topped by a short square section
under the head. They are the most commonly used
with wood.
stainless steel 18-8 carriage bolt non-corrosive, common for marine and outdoor use price starts at $2.70/bag
zinc plated carriage bolt copper alloyed with 1-3% silicon, great resistance to corrosion from strong chemicals price starts at $1.25/bag
