WORKSHOP LENGTH CHECKSSource-based notes · UK English
MeasureProofSHOP CHECKS, NOT CERTIFICATES

THE BENCH NOTES

Workshop notes

How a small shop records a length check, and what that record is not.

MeasureProofUpdated
Still-life of an outside micrometer, gauge blocks and a blank grid sheet on a wooden bench.
Explanatory still-life of the shop-check ingredients. Not a MeasureProof test.

Which question should you open first?

Each note below explains one workshop method or one distinction that the cited sources already make. Inch figures stay in inches. Millimetres are the default unit for a UK shop record. This publication has not published original gauge-block repeats. Open the note that matches the instrument in front of you, and keep a shop check separate from a certificate.

Still-life of an outside micrometer, a stack of steel gauge blocks and a blank grid sheet on a wooden bench.Source-based note

Checking a 0–25 mm micrometer with gauge blocks

What a workshop record of repeats on known blocks can show, and why it is still not a UKAS certificate.

8 MIN READ Still-life of an outside micrometer beside gauge blocks of several different lengths on a light wooden bench.Source-based note

Zero and full scale is not enough

Why a zero setting plus one full-range block can miss mid-travel error, using Sparber’s published inch table as the example.

7 MIN READ Still-life of a digital caliper with a blank display, a ring gauge and a gauge block on cream paper.Source-based note

Caliper outside, inside and depth are different checks

An outside-jaw reading on a gauge block does not pass the inside jaws or the depth rod. Keep the three faces in separate columns.

8 MIN READ Still-life of a blank lined notebook, a steel gauge block and a sealed kraft envelope with an empty label.Source-based note

Workshop check versus a UKAS certificate

A gauge-block comparison in the shop, a manufacturer inspection sheet and a UKAS certificate answer different questions.

7 MIN READ Close still-life of a digital caliper head with a dark, blank display.Source-based note

Resolution is not capability

Display resolution, a stated accuracy figure and the scatter of a real check are three different numbers. Keep them in three columns.

6 MIN READ

What do these notes cite, and what do they leave out?

The notes cite identifiable workshop publications and UK length guidance, and they attribute sample measurements to those authors. They do not add a MeasureProof gauge-block series, and they do not convert an inch table into a British typical error. A forum thread can show the question people ask. It does not establish the correct answer.

  1. NPL Good Practice Guide 40, Callipers and micrometers ↗UK use conditions for force, cleanliness and temperature. It is not a workshop certificate.
  2. Sparber, How Accurate is Your Micrometer? ↗Personal workshop PDF. The inch table is the author’s instrument, not a MeasureProof test.
  3. Machinist Guides, Beginner’s guide to micrometers ↗Procedure writing, not an original repeatability table.
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