Step 6 · Secure the New Faucet
From underneath the sink, slide the provided friction washers (if any) and then the mounting nuts onto the faucet's threaded shanks. Hand-tighten the nuts until they are snug. Before the final tightening, have someone look at the faucet from above to ensure it is perfectly aligned and centered. Once aligned, use the basin wrench (or a special socket tool that often comes with new faucets) to tighten the mounting nuts. Tighten them firmly to secure the faucet, but do not overtighten, as this can damage the faucet or the sink.