Gauge Blocks

Gauge Blocks:

Gauge blocks are precision-machined blocks that are designed for calibrating measuring devices and for use as precision measurement devices.

Also called Jo blocks, a reference to their inventor, Swedish engineer and machinist Carl Johansson, they are created in sets containing many different sizes, so that they can be combined various ways to make up almost any desired measurement, up to several inches (1 inch = 2.5 cm).

They are usually made from high grade steel or carbides that resist wear and damage. A gauge block is machined to have two sides that are perfectly flat within very small tolerances, and that are parallel to each other.

What are gauge blocks used for?

Gauge blocks are used to calibrate engineering equipment, (e.g., micrometers and Vernier calipers). Higher grade gauge blocks can also be used to calibrate other gauge blocks of the same or lower grade. Finally, gauge blocks can be used with coordinate measuring machines (CMMs) as part of an ISO 10360 CMM reverification test or as a reference artefact when using the substitution method according to ISO 15530-3.

Gauge Block is manufactured and shaped with a high degree of accuracy, so special treatment is needed.

Guide on Selection of Gauge Blocks:

  • Select the size of the gauge block by the range of holes, slot, and spaces dimensional requirement. Sometimes, you can already find the exact length of gauge block that you need in our gauge block sets. However, in case you need to make a certain new length, you have to wring and stack the gauge blocks depending on the size requirement you need.
  • During the stacking and wringing gauge blocks process, always make sure to use the minimum number of blocks as possible to prevent errors or variations in measurement of length because the more step you make, the higher error you can get. Therefore, if you have to measure longer lengths, you must always select thicker gauge blocks to wring whenever possible.
  • Do Math. Always consider the least significant digit of the lengths of the gauge blocks to wring.

Before using gauge blocks:

  • Check if your gauge block sets are complete and properly arranged in their location.
  • Inspect the appearance of the gauge blocks. There should not be any burrs, nibs, dirt, corrosion, or excessive oil.
  • Wipe excess oils of the block that you will use if necessary using a lint-free cleaning paper or cloth.
  • Clean the gauge blocks by using cleaning oil together with a lint-free paper or cloth.
  • Wipe excess oils of the block that you will use if necessary using a lint-free cleaning paper or cloth.
  • If you have designated staff for controlling your measuring tools and equipment, report the problems you encountered. However, if you know the basics of maintenance of gauge blocks, you should do immediate action to address the problem.
  • Do not use the gauge block if the abnormalities observed were not addressed.

During using gauge blocks:

  • Do not drop, toss and damage your gauge block.
  • Use gloves when holding gauge blocks. Steel gauge blocks are prone to corrosion.
  • Always follow the proper way of wringing your gauge blocks as thin gauge blocks can easily be bent, and scratch and burrs will always be possible if the wringing process is not done correctly.
  • Observe if your gauge blocks can still be wrung. The inability of gauge blocks to be wrung might mean that there is already a problem with your gauge blocks. remember that its super flatness and super smoothness cause the gauge blocks to be wrung.
  • Do not leave your gauge blocks wrung overnight or over a long time.
  • Do not abuse the use of gauge blocks. Control the use of gauge block during measurement specifically in a Go-No Go gauge checking.
  • If there is a possibility that gauge block might be used excessively, always use the wear blocks as the end of a stack to prevent your gauge blocks from being worn out. Having a spare gauge block is more convenient.
  • Use gauge block accessories such as a holder when it is necessary. Holders, connectors, and rods add security to prevent the gauge blocks from dropping and to prevent errors on measurement.
  • Always check the condition of the tools or the parts that will be checked by the gauge block. It should not have burrs or any abnormalities that might damage the gauge blocks.
  • Do not place the gauge blocks everywhere. You might lose or damage the gauge block if not placed in a proper place. You can use a rubber mat where you can temporarily place the gauge blocks during use.
  • Do not use gauge blocks in any other area other than the inspection area. Since gauge blocks are stored in a controlled environment, they should also be used in an environment where the temperature is properly controlled as it was stored.

After using gauge blocks:

  • Make sure to clean the gauge blocks after use.
  • Inspect if there are scratches, burrs, nibs, dirt, rust, excessive oil, or any other foreign material that might have been caught up on the blocks during use.
  • Remove any dirt, dust, and other foreign material using cleaning oil. Use lint free paper or cloth.
  • If there are burrs, deburr the gauge blocks using the designed abrasive stones for deburring gauge blocks.
  • Place gauge blocks in their proper location.
  • Do not store gauge blocks in one space where each gauge block might be touching one another. It will cause possible damage to the blocks.
  • Do not store gauge blocks in open space. Always close the lid. Steel blocks are more prone to corrosion than ceramic gage blocks, therefore humidity has to be considered.
  • Always control the temperature where you store your gauge blocks. The temperature must be controlled ideally to 68ºF/20ºC as defined by NIST which is the standard reference temperature for industrial dimensional measurements.