Building a wooden arch or garden arbor involves measuring, cutting and assembling the pieces before erecting the arch. Simpler arch designs may require no more than six pieces, while designs featuring multiple pieces require more complicated assembly. Dig post holes for added stability when erecting an arch, and pour concrete after ensuring the arch is plumb and level.
After assembling all material and any plans or diagrams that provide dimensions and measurements for the arch, measure and notch the beams with a circular saw, cutting as deep as possible before using a hand saw to finish the cuts. Cut the straight edges of the brackets using a circular saw and use a jigsaw to cut the arcs. Use a belt or orbital sander to remove any excess materials and ensure smooth lines.
Fasten the sections together by screwing through the posts and brackets and into the header. Screw through the second header and into the posts. After preparing post holes, use an assistant to help steady the arch and ensure that the final position is plumb and level. Pour concrete into the post holes and then allow it to harden for at least four hours before painting, staining or finishing the wood.