Slip gauges are rectangular blocks made of alloy steel that are used as standards to check the accuracy of measuring instruments. They are hardened, quenched, and superfinished to achieve a very high level of flatness and parallelism on their contact surfaces. Slip gauges are supplied in sets of different sizes so that various length combinations can be obtained through stacking.

1. • Slip gauges are used as standards of measurement for
checking the accuracy of measuring instruments such as
micrometers, vernier calipers, snap gauges, dial gauge
indicators etc.
• These were invented by C.E. Johannsen of Sweden,
therefore, named as "Johannsen gauges
• Slip gauges are referred as 'Precision gauge blocks'.

2. 1. Slip gauges are rectangular blocks of section 30 mm x
10 mm x thickness (as required).
2. 'Alloy steel' is the most commonly used material for
making slip gauges.
3. They are hardened and quenched before being
finished to required size.
4. In order to obtain a very high order of accuracy in
flatness and parallelism of opposite faces, the contact
surfaces of slip gauges are superfinished by grinding
and lapping.

4. Sets of Slip Guage
• Slip gauges are supplied in different sets of suitable
sizes, so that, number of combinations may be obtained
for building up required lengths or heights.
• Commonly used sets are M 45 and M 87 pieces

5. Wringing is the process of sliding two blocks
together so that their faces bond. Because
of their ultraflat surfaces,the atmospheric air
between the two mating surfaces of any two
guage block , so that the blocks stick each
other due to vaccum

6. 1. They universally accepted as a “Standard of length”.
2. They used for direct precise measurement where
accuracy of work piece being measure is high.
3. They used with high-magnification comparators, to
establish the size of the gauge blocks.
4. They are used for checking the accuracy of measuring
instruments.
5. They are used to setting up a comparator to specific
dimension.
6. They are used to check a batch of components quickly
and accurately.