🔍 Key Concepts

• Globe valve construction – how the disk and seat make a tight seal • Machining vs. abrasive cleaning – which restores a precise sealing surface, and which can damage it • Typical shipyard practice for repairing metal valve disks that are eroded or pitted

💭 Think About

• Which method will restore the original, precise shape and angle of the disk so it can seat properly again? • Which options are more like ‘cleaning/polishing’ and which are true ‘re‑machining’ or metal‑cutting methods? • Think about surface flatness: which process gives you a controlled, uniform metal removal instead of uneven hand work?

✅ Before You Answer

• Identify which choice is a machine cutting operation rather than a hand‑finishing or cleaning step • Ask whether the method can hold a precise angle and concentricity between disk and seat • Eliminate any option that would leave a rough, scratched, or uneven sealing surface instead of a smooth, machined one