5/16-18 X 3-1/2" 馬車螺栓 | 全螺紋 | A307 Grade A 普通鋼 (100個/包)

The square neck grabbed tight into the wood just as described, no spinning at all when I tightened them. For a 3.5-inch bolt they feel solid enough for heavy furniture assembly.

These are exactly the right length for joining my planter boxes together, and the fully threaded shaft gave me plenty of grip when I tightened them. The square neck locked into the wood just like it should, so no spinning or cursing on this project.

The square neck under the head bit right into the wood on my deck repairs and held firm while I torqued them down. All 100 bolts came threaded clean with no burs, and the 3-1/2 inch length is perfect for sandwiching two 2x4s. Finished my project in under an hour without a single stripped thread.