Using a gauge block is not complicated but there are several things you have to master; have to learn at least. Because this block is manufactured and shaped with a high degree of accuracy, a special treatment is needed. This page will walk you through how to use the gauge block from the selection up to how to use it, even how to maintain it.
You will read how to select the gauge blocks so that a new length is formed. If the block length you require is not available in the block set, you have to learn this selection. Then, you will read about the wringing and stacking guide. Forming a new length requires a method called wringing and stacking. Unfortunately, you cannot wring it perfunctory. It can generate an inaccurate new length which further generates an unreliable measurement. Lastly, you will read how to take care of gauge blocks.
As we have learned before, a gauge block is a working standard for length in our workshop. It’s also the reference standard for length in the metrology lab. That’s only a matter of grades. The guide on how to use the gauge block of this article cover most gauge block grades.
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.
a. How to Select the Blocks for Wringing (in): Example 1
In this case, we use Mitutoyo 516-404-26 gauge block set that has grade ASME AS-2. This set has 81 blocks which the following table is what you can see the blocks and their lengths.
The problem is what blocks to pick to form a 1.1284″ gauge block in which this length is not available in the set.
|Block Length (in)||Number of Blocks||Increment/Step (in)|
|.1001 up to .1009||9||.0001|
|.101 up to .149||49||.001|
|.05 up to .95||19||.05|
|1 up to 4||4||1|
As usual, you define the least significant digit that is 4.
However, the block of .0004″ is not available. Nicely, the block of .1004″ is available. Pick it and subtract.
1.1284″ − .1004″ = 1.0280″ ………(1
For 1.0280″, the least significant digit is 8. Look for the blocks with nominal “8” in the third decimal place. However, the blocks of .008″, .028″, 1.008″, 1.028″ are not available. But, the .108″ and .128″ blocks can help. Pick the .128″ block to prevent many gauges to wring; pick the thicker one.
1.028″ − .128 = .900″ ………(2
The .900″ block is available.
.900″ − .900″ = 0 ………(3
Finally, you just need 3 blocks that have lengths of .1004″, .128″ and .9″. If you want to learn more, perhaps this page is helpful for you. http://www.starrett-webber.com/GB49.html
b. How to Select the Blocks for Wringing (mm): Example 2
You were given a required length to measure, for example, 27.075 mm. And you have a Mitutoyo 516-937-26 gauge block set. What blocks to pick for wringing?
As we know that Mitutoyo 516-937-26 contains 122 steel blocks as shown in the above photo. The available block lengths are in the following table. That said, the 27.075 mm block length is not available as default. A wringing is the problem solver of these limited blocks.
|Block Length (mm)||Number of Blocks||Increment/Step |
|1.001 - 1.009||9||0.001|
|1.01 - 1.49||49||0.01|
|0.5 - 24.5||49||0.5|
|25 - 100||4||25|
Firstly, select the block that has the least significant digit. But make sure it’s available in the block set.
For 27.075 mm, the block of .005 mm is not available. The block of .075 mm is also not available. But, the block of 1.005 is available. Pick that 1.005 mm block as the 1st gauge block. Subtract this to the required length.
27.075 mm − 1.005 mm = 26.070 mm ………(1
For 26.070 mm, the block of .070 mm is not available. But the block of 1.07 mm is available. Pick it and subtract.
26.07 mm − 1.07 mm = 25.00 mm ………(2
The 25 mm block is surely available.
25 mm − 25 mm = 0 ………(3
Overall, you just need 3 blocks that have lengths of respectively 25.00 mm, 1.07 mm, and 1.005 mm.
How about if you only have 100 gauge blocks, can you pick the correct blocks to form a length of 27.075 mm?
Wringing Gage Blocks
Aside from the precision and accuracy of gauge blocks, one major characteristic of gauge blocks is their ability to wring together.
Wringing is the process of sticking two opposite measuring faces of the gauge block in order to make a certain new precise length that is not available on the set. It does not need any adhesives or magnetism for the gauge blocks to stick to each other.
This phenomenon was mostly debated over time to know what is the real reason behind these gauge blocks stick to each other when a wringing process is correctly done. Here are some of the popular explanations for the wringability of gauge blocks: air pressure, surface tension from the oil, and attractive molecular force that occurs due to the interchange of electrons between the atoms of the blocks. Reference: http://www.starrett-webber.com/gb46.html
For the process of wringing you should consider the shape and length of your gauge block.
Below is the proper way of wringing the gauge blocks. But before you start wringing, make sure that the gauge blocks are cleaned. There have to not be any burrs, dirt, or corrosion on the gauge blocks. Apply a very little amount of oil or petroleum jelly on your gauge blocks then wipe it on a wipe pad to make sure that the remaining oil is only minimal.
a. Wringing Process of Two Thick Gauge Blocks
1. Gently slide the gauge block on the top while you cross the gauge blocks at nearly 90° on the middle of their measuring faces.
2. Gently rotate the gauge blocks with slight force applied. As you rotate the block, you can feel that the sense of wringability where blocks ought to stick together.
3. Make sure to properly align the wrung measuring faces of the blocks.
b. Wringing Process of Thick and Thin Gauge Blocks
1. Gently slide the edge of the thin gauge block on top of the thick gauge block until it reaches the other end.
2. Make sure that the two gauge blocks are properly aligned.
c. Wringing Process of Two Thin Gauge Blocks
1. To prevent the thin gauge from getting bend during the wringing process, first, get a thicker gauge block as a base.
2. Slightly wring the thin gauge block to the thick gauge block.
3. Next, wring the other thin gauge block onto the first thin gauge block.
4. Slightly remove the thicker gauge block from the stack that was used as a base.
d. Wringing Process of Square Gauge Blocks
1. Slightly slide the gauge block on a diagonal position starting from the corner of the square gauge block.
2. Slightly rotate the gauge block.
3. Make sure to align the gauge block exactly on top of each other.
Other Ways of Stacking Gauge Blocks
There are several ways to combine gauge blocks except wringing. A stack of gauge blocks can be clamped together. You could use a gauge block holder for a rectangular gauge block. On the other hand, you can insert a rod into the center hole of a square gauge block.
The gauge block holder typically comes as a set with other different sizes of holders. This allows you to form multiple different sizes of gauge blocks as well.
Other accessories that work with gauge block together with the gauge block holder and base holder to have a precise gauge are the sine bar or the scriber point for height and angle reference and measurement, round or half-round jaws for gauging bores, or reference of cutting and mounting tools, and connector for setting up dial indicator.
These accessories were combined to gauge blocks to perform a certain function for length standardization.
The video below is the perfect presentation for you to know more about these gauge block holders.
How to Take Care of Gauge Blocks
For our measuring tool to function precisely and to get accurate measurements during inspection of our manufactured goods, you should treat gauge block with respect and care.
Learn to take extra care of our gauge block, before, during, and after use. You should also set a periodical check-up for our gauge blocks called calibration conducted by a certified calibration laboratory to monitor even maintain their precision and accuracy.
The calibration laboratory and its accreditation body should be traceable to the BIPM metrology chain. It’s always advised to check whether they are accredited to ISO 17025 or not. Keep in mind that it has to be accredited, not complied. It’s not a must but will ensure everything passed the agreed standard.
Do’s and Don’ts before use
Check gauge blocks before use. Gauge blocks must always be in good condition before use.
- 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.
Do’s and Dont’s during use
Handle the gauge blocks with extra care during use.
- 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.
Do’s and Dont’s After Use
- 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. Manufacturers of gauge blocks also offer deburring stones. For example, Mitutoyo has Ceraston. Follow the manufacturers’ instructions on how to properly deburr 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.