Which capacity applies to fixed-adjustment tools in the ISO 6789-1 overloading test?

Check the capacity reference and the next sentence

Open 5.1.6 and locate “D, E and F” beside nominal capacity. Do not extract those letters alone to build a procedure. Read the next sentence as well: its adjustable-tool list includes A/C/D/F/G, placing D and F in a setting-adjustment context. Treating all the classes in the preceding list as fixed-adjustment tools would leave the roles in those sentences inconsistent.

Then check Clause 4. B identifies a fixed-adjustment wrench and E a fixed-adjustment screwdriver. D is an adjustable screwdriver with graduations or a display; F is an adjustable, non-graduated screwdriver. Non-graduated does not mean fixed adjustment, and the tool’s appearance cannot replace this classification check.

Why we read the reference as B/E

First distinguish the capacity bases. Adjustable tools have a maximum torque and an adjustment range, while a fixed-adjustment tool’s nominal capacity corresponds to its fixed setting. Assigning D and F to the fixed-adjustment basis conflicts with their adjustable nature and with the setting instruction that immediately follows. Meanwhile, the fixed-adjustment class B is absent from that capacity reference.

In ISO 6789:2003, 5.1.6 lists B/E at the nominal-capacity reference, providing another clue through comparison of the editions. We adopt this reading because it fits both the classification and the surrounding text in the clause. A difference in another year’s wording alone would not justify replacing the text of this edition.

The question is therefore which classes belong with nominal capacity. It does not establish that all screwdrivers use nominal capacity or that every non-graduated tool has fixed adjustment. Identify the actual tool before choosing the basis.

Document the capacity used in the test

Record the standard edition, clause, original wording, and adopted reading together. Retain D/E/F as the printed entry and explain separately that the classification supports a fixed-adjustment B/E reading. Record the actual tool’s nominal capacity and the source of that information so that a reviewer can follow the connection between classification and the chosen numerical value.

When calculating the test load for a fixed-adjustment tool, use its verified nominal capacity as the basis. For an adjustable tool, establish maximum torque and setting conditions from the applicable provisions; do not create another procedure from this issue. This article addresses the relationship between class and capacity. The applicability, steps, and post-test requirements still need to be read in full, and our interpretation is not permission to overload a tool in ordinary use.

This is our reading, not an official ISO corrigendum. ISO is revising Part 1 and Part 2 through committee drafts ISO/CD 6789-1.3 and ISO/CD 6789-2.3. We will update this page and recheck the issue when the revised standards are published.