An explanation of the aluminium port relief block on the hammer valve and why it is essential for protecting seals and rope under sudden pressure spikes. Tony covers how the spring-loaded needle valve diverts oil into the exhaust manifold when flow is stopped abruptly, how to adjust relief pressure using an 8mm Allen key and 19mm lock nut if hammer speed drops, and why you must always confirm the relief is cracking active before locking off — a short drop on oil should be audible.