Okay, let's break down what's likely being asked for based on the images and your question.

Understanding the Terminology Bore

A cylindrical hole. In manufacturing drawings, it often refers to a hole that is specifically created for a tight-fitting part or component.

Threaded Opening (Thread)

A helical ridge or groove cut into a hole or on the outside of a cylinder to allow for screws, bolts, or other threaded fasteners.

Thread Relief

A feature added to a threaded opening or external thread to provide space for the threading tool to run out when cutting the threads. This helps ensure the threads are complete and of good quality.

Interpreting the Drawing and Question

Given that the callouts in your image are pointing to the inside diameter of what appear to be holes, and your question asks about "threaded opening," it's highly probable that the specifications are related to threaded holes.

My Best Guess (with a disclaimer!) "Bore X.XXX (THRU)": This likely indicates a standard (non-threaded) hole needs to be present with specified diameter `X.XXX` that is to cut through the material. "THREAD RELIEF PER SPEC YYYY": This is the critical piece. It means that there needs to be thread relief (a space at the bottom of the hole) to a separate specificiation `YYYY`. You'd need to consult the YYYY document to understand how large and what the characteristics of the relief is.

Why Thread Relief Matters Complete Threads

When you tap threads, the tap needs space to run out at the end of the hole. Thread relief ensures you get complete threads to the very bottom of the tapped section.

Avoid Bottoming Out

Without thread relief, a screw or bolt might bottom out against the non-threaded material before it fully engages with the threaded portion, leading to inaccurate tightening and potential stress on the bolt or threads.

Manufacturing

Thread relief can simplify the tapping process, especially in blind holes.

Important Considerations1. The Crucial Specification "YYYY"

The most important thing you need is the

actual document "YYYY" that is being referenced for the thread relief. That document will contain the critical dimensions, tolerances, and other requirements for the relief. Ask the design engineer or whoever provided the spec for this specification document if you don't have it.2. Blind vs. Through Holes

The drawing needs to clearly indicate whether the holes are blind (not going all the way through) or through (passing entirely through the material). Thread relief is particularly important in blind holes.

How to proceed Locate Specification "YYYY"

This is the most important step.

Clarify with the Engineer: If anything is still unclear, don't hesitate to ask the design engineer or the person who created the specification for clarification. It's far better to ask questions upfront than to make assumptions that could lead to errors. Flag for review