When it comes to metrology in the workplace, the more specialised industries depend on instruments such as micrometers to ensure the most accurate measurement standards are being met.
While a handheld micrometer provides a precise way of measuring small objects there is sometimes a big advantage to be gained by using the stability of a bench micrometer. Take it a step further and you will find that a digital bench micrometer (sometimes referred to as super mics) can give you an even higher degree of accuracy.
Bench micrometers are used for outside diameter measurements and they are now created with electronic digital readouts that can be saved and stored on other devices.
The highest quality bench micrometers, such as those produced by companies such as Pratt & Whitney, are incredibly impressive machines that are capable of measuring just about any manufactured precision part. These gauges are used to measure small items such as pins and plugs as well as any type of thread.
Different Types of Micrometers
Let’s do a quick recap of the different types of micrometers that are most commonly used.
There are three types of micrometers that are used in the normal course of a job:
Outside Micrometer - these are the most commonly used micrometers and are used to measure the external dimensions of small objects. You will get the most accurate results when the measuring faces are placed against flat, parallel surfaces. We have actually put together a pretty swish examination of outside micrometers here.
Inside Micrometer - not quite as regularly used, however in some industries they are a key piece of measuring equipment. They measure the inside dimensions of objects such as the inside diameter of a hose or pipe. These instruments consist of the spindle and sleeve that you see on a conventional micrometer and measuring rods of different lengths.
Depth Micrometer - as the name implies. These micrometers are used to gauge the depth of a hole within an object. This micrometer works by placing the base of the device on the top of the hole and then sending a rod down by turning the thimble until it touches the bottom and the measurement is taken.
Other types of micrometers that it may be worth being aware of include:
- Blade micrometer
- Disc micrometer
- Tube micrometer
- Screw thread micrometer
- Taper micrometer
Bench Micrometers vs Handheld Micrometers
If you perform a lot of work in a single location such as your workshop then it will make a lot of sense to install a bench micrometer. Similarly, if your work requires measurements of far greater precision, the bench micrometer will be necessary.
In many cases bench micrometers are built so that even more precise measurements can be taken. Whereas you can expect to take a measurement with an accuracy down to one-thousandth of an inch (+/- 0.0001”) with your handheld micrometer, it is possible to get to an accuracy of around half a micrometre (around 20 millionths of an inch) when using the bench micrometer.
Because the micrometer head is mounted on a rigid base, your hands will be left free to manipulate the object being measured in any way you require.
Examples of Digital Bench Micrometers
To give you an idea of what they might look like and the options available at either end of the cost spectrum, we have provided examples of a few models of digital bench micrometers below.
This is the Starrett Electronic Bench Micrometer. It has a measuring range of 0-1” and features a large easy-to-read LCD digital screen. It also has the ability to output the data that is captured with the connection of a cable to the PC. Visit the Starrett website for more information.
The state of the art Pratt & Whitney External SuperMicrometer has the ability to measure both internal and external parts. It is a high precision metrology device that is packed with an impressive array of features that are all designed to ensure the greatest possible precision in measurement. Visit the Pratt & Whitney website for more information.
The E.J. Cady DDW Digital Bench Micrometer (pictured above) is another option that provides highly accurate measurement capabilities as well as being able to collect and collate the results on a computer. The company actually makes two models, one that is operated manually with a lever activation and the other, the DDW-T, being automatically initiated through keyboard operation. Visit the E.J. Cady website for more information.
The Nikon MF-1001 Bench-Top Micrometer has a measuring range of 100mm and is designed to measure dimensions, thickness and depth and has an accuracy of 1µm at 20° C. Visit the Nikon Metrology website for more information.
The Tesa Interapid SHE.30 series of bench micrometers are said to be ideal for precise inspection of small parts and perfect for industries such as watchmaking and precision mechanics. Visit the Tesa Technology website for more information.
The Accurate Bench-Top Digital Micrometer has a measuring range of 175mm and it offers effective calibration of Thread Plug Gauges and Taps. It is also possible to add accessories such as thread measuring wires, prisms, cylindrical masters and taper thread plug attachments to it to enable major and minor diameter calibration of threads.
As can be seen from the range of products that are quickly examined above, there are quite a few different options to look at when it comes to digital bench micrometers. Each provides a subtle difference when it comes to the specialty in which it operates. It is worth visiting the company sites to find out more information about any of the types displayed.
When it comes to the bench micrometer, the point to remember is that it comes down to the level of precision that is possible. The smaller handheld micrometers will give you a good level of accuracy for most work you might do, but for the greatest possible level of precision you will want to go with the bench top micrometers.