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

NOTES ON SHOP LENGTH CHECKS

A gauge block
is a check.
Not a certificate.

How a small workshop records a 0–25 mm micrometer or digital caliper against known blocks — and what that record still is not.

Source-based notes for UK model engineers, incoming inspection and small machine shops. MeasureProof is not a UKAS laboratory.

MeasureProofUpdated
Start with the micrometer check ↗How evidence is used
STILL-LIFEREFERENCE ≠ RESULT
Still-life of an outside micrometer with a thin steel gauge block standing in the measuring opening on a wooden bench
Explanatory still-life. Not a recorded check.The reading still has to be written down.
01 Name the block02 Record the temperature03 Write the repeats down

WHAT THIS SITE DOES

What does a workshop gauge-block check show?

A workshop check records how one named 0–25 mm micrometer or digital caliper reads known gauge blocks, with the temperature and the contact method written down. It can show scatter and a difference from the block size. It does not make the instrument calibrated, and it is not a UKAS certificate. These notes interpret published methods and UK metrology guidance. This publication has not published original gauge-block repeats.

DocumentWhat it can support
Workshop checkObserved readings on named blocks, at a recorded temperature and contact method.
Manufacturer inspectionThe maker’s outgoing test. It is not a UKAS certificate.
UKAS certificateA defined object, date, method and stated uncertainty from an accredited laboratory.

Use conditions are described in NPL Good Practice Guide 40. A published inch example of mid-range error is Sparber’s micrometer note.

01 / THE BENCH

Workshop notes

Repeats, mid-range checks, and why zero plus full scale is not enough.

Open the workshop notes ↗02 / THE DISTINCTION

Three kinds of document

Shop check, manufacturer inspection and a UKAS certificate.

Read the methods ↗03 / THE RELATIONSHIP

Related retail shops

accumeasure.co.uk and proster.co.uk are commercially related.

Read the disclosure ↗

START WITH THESE NOTES

How is a stated ±0.02 mm different from a measured result?

Display resolution, a manufacturer specification and the scatter of a real check are three different numbers. A stated ±0.02 mm is still only a statement in a manual. These pages publish explanations and a blank record. They do not include original repeats from this publication, and they do not treat that statement as a result measured here.

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