When making a lead and oakum joint on bell and spigot pipe, the minimum depth of the lead in the joint shall be ____________.

The minimum depth of the lead in a lead and oakum joint on bell and spigot pipe is specified as 1 inch. This depth is crucial for ensuring a watertight seal between the pipes. A lead depth of 1 inch allows for adequate material to fill the joint, compensating for any irregularities in the pipe surfaces and preventing leakage.

Using 1 inch as the minimum ensures that there is enough lead to form a strong bond when the joint is made, allowing the oakum to be packed tightly around it to create a secure seal. This depth is consistent with accepted plumbing standards and ensures the durability and reliability of the connection in a plumbing system, minimizing the risk of future leaks.

Other suggested depths may not provide the same level of effectiveness in ensuring a tight and long-lasting seal, which is why 1 inch is the established minimum in this type of joint.