A tube-sheet enquiry describes a pattern as well as individual bores. Keep hole identity connected to the machining and inspection records so a completed program count cannot hide a missing or interrupted result.

The hole map is the common reference

The illustration below is an assumed six-hole map, without design dimensions or production data. For each ID, retain the coordinate reference, entry and exit faces, bore requirements and applicable setup. The same ID should identify the program event and inspection record.

If a setup changes, retain which holes belong to each position. A good result on A1 cannot document a different coordinate transformation or location used for B3. The actual drawing controls the geometric and joining requirements; this record example does not supply them.

Make exceptions visible

Consider an illustrative log in which six hole operations start, B2 is interrupted and the other five finish. “Six started” is a different statement from “six completed,” and both differ from the accepted-hole map. Keep B2’s disposition with its ID through later inspection or rework.

A summary report should therefore link to the supporting map rather than replace it. State which characteristics were inspected at which holes, and preserve any uninspected region or agreed sampling basis.

Do not infer a BTA production case from a service description

TBT’s subcontracting page establishes an offered machining service. It carries no verified BTA tube-sheet acceptance dataset. No throughput, pattern accuracy or joining qualification is claimed here from that service listing.

Use the quality worksheet to define the individual requirements and attach the agreed hole map in the actual job record. Continue to automation and record flow for keeping identity across stations, or first-article inspection for the initial evidence package. A genuine case can later add its actual conditions and results without changing the identity scheme.

Revision note

October 8, 2026: revised the technical explanation and connected reading after source review. Original publication date and URL retained.