When constructing or repairing park benches, selecting the proper fasteners for attaching the wooden slats to the frame is crucial for both safety and longevity. The most common and reliable fasteners used for this purpose are lag bolts (also called lag screws) and carriage bolts.
Lag bolts are particularly effective for securing wood to metal frames. These heavy-duty screws feature coarse threads and a hexagonal head that requires a wrench for installation, creating an incredibly strong connection. For wood-to-wood connections on park benches, carriage bolts are often preferred. Their smooth, rounded heads prevent snagging on clothing, while the square section beneath the head locks into the wood to prevent spinning during nut tightening.
Proper installation techniques are equally important. Always pre-drill pilot holes slightly smaller than the fastener diameter to prevent wood splitting. For maximum weather resistance in outdoor settings, choose hot-dipped galvanized or stainless steel fasteners that won't corrode over time. Washers should be used under bolt heads and nuts to distribute pressure evenly and prevent the fastener from pulling through the wood.
The spacing of fasteners also matters significantly. Typically, you'll want to place two fasteners per bench slat where it meets the frame, positioned about 1-2 inches from each edge. This configuration provides optimal stability while allowing for natural wood expansion and contraction due to temperature and humidity changes. Regular inspection and maintenance of these connections will ensure your park benches remain secure and functional for years to come.