Lag Screw Pilot Hole Diameters

Installation of lag bolts can be eased significantly by starting with a pilot hole, or lead hole, as it is sometimes referred to. The chart below can be used to identify commonly accepted hole sizes. A number of variables that may change the required pilot hole dimensions, such as bolt diameter, length, and species of wood that you're screwing into. For questions about pilot hole sizes in specific applications, consult with an engineer.

Click here to download a printable PDF chart of these lag bolt pilot hole diameters.

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