What is a T-nut and how does it work? How do you fasten ‘Bolt-on’ climbing holds to wood climbing walls? This guide is intended to be a quick explanation for customers who are brand new to climbing. Prior to fastening bolt-on climbing holds to wood climbing walls, t-nuts must be installed in the back of the climbing wall. The bolt will go through the climbing hold, through the wood, and into the t-nut. A t-nut is basically a nut with a flange on one side. If you need help installing t-nuts check out our instructions here: How to Install t-nuts The barrel of the t-nut can fit into a 7/16” hole, but the flange is 1” wide so it cannot fit through the hole. The flange catches the surface of the climbing wall surrounding the 7/16” hole. The Barrel of the T-nut should be recessed behind the front surface of the climbing wall by at least 1/ 4”. Climbing holds must not make direct contact with the t-nut. If the climbing hold makes direct contact with the t-nut it will eliminate the friction between the surface of the climbing wall and the back of the climbing hold. Climbing holds must have good contact with the climbing wall in order to be secure. Let us know if you have any questions! Home - Product Info - Climbing Holds FAQ - New Climbing Holds - Climbing holds for bouldering - Jugs - Crimps - Incut Holds - Starter Sets - Kids Climbing Holds - Screw on Holds - Novelty Climbing Holds - Hardware for climbing holds - Shipping Information - Climbing Wall Plans - About Us - Pics & Vids - Contact Us - Related Sites - Project Holds