When you choose a caliper measuring tool, which type is the best option? People have different preferences and calipers come in varying features and specifications. In this article, we are going to analyze the details of dial calipers, digital calipers and vernier calipers. Starting from the working principle, more importantly, dial vs. digital vs. Vernier caliper, what’s the difference between them?
A dial caliper is a measuring tool that features a dial indicator that allows users to read the results easily. The dial indicator is a mechanical system that consists of a rack and pinion, the inside gear moves the dial in increments of one-thousandth of an inch. You should read the value from the ruler and the fractional value from the dial. From its working principle, it is a kind of measuring tool that changes the relative movement of two measuring claws into the rotary movement of indicator pointer through gear transmission system, and reads the distance separated by the relative movement of two measuring claws with the help of ruler scale and indicator.
A digital caliper is a measuring tool for length, inner and outer diameter and depth. How does a digital caliper work? Unlike dial calipers and vernier calipers, the working of digital calipers involves capacitance sensors and circuit boards. Underneath the scale of the caliper, there are multiple rectangular plates engraved onto a copper or glass strip, and the circuit board on the underside of the movable jaw forms a grid of capacitors with the copper plates. When the sliding jaw travels along the main scale, the plates will become align and misalign, the capacitance or electrical charge between plates will change. The capacitance sensors will detect changes in electrical charge and send a signal to a chip within the caliper, which generates the readings displayed on the LCD screen. Using the digital caliper, the measurement results are displayed digitally, so the reading is more intuitive and convenient, the efficiency is improved, and the visual error is reduced. Digital calipers can also convert between both metric and inches quickly.
A vernier caliper is named after Pierre Vernier, is a measurement tool to get accurate readings between two graduation markings on a linear scale by using mechanical interpolation. A vernier caliper has a main scale (fixed) and a vernier scale (movable), the main scale has standard resolution with a least count of 1mm, and the vernier scale is attached to the main scale has finer divisions. For a vernier with a constant of 0.1, each mark on the vernier is spaced 9/10 of those on the main scale, the vernier divisions are marked from 0 to 9 and 0 again, if make these two scales align on zero point, the division on the vernier lags the main scale by 0.1mm, the first mark on the vernier scale is 1/10 shorter than the first mark on the main scale. Only one pair of marks aligns then it will show the value between the marks on the fixed scale. For example, if we move the vernier by 1/10, the first pair aligns. This is how the interpolated reading is obtained for higher resolution.
– Dial calipers do not need a battery, while digital calipers need.
– Digital calipers are easier to read than the dial type, as they can displays the measurement directly.
– Dial calipers use a rack-and-pinion system, while digital calipers apply circuit boards and sensors.
– Dial calipers typically come in either metric or imperial, but a digital caliper features both two.
– Dial calipers are usually more affordable than digital calipers.
– Dial calipers only come in a single unit system, a digital caliper can show both.
– Digital calipers have a greater resolution than vernier and dial calipers.
– Digital calipers are more resistant to knocks.
– The dial caliper can have a higher resolution than a vernier caliper.
– The dial caliper is easier to read than a vernier caliper.
– A vernier caliper is generally more cost-effective.
– Dial calipers are only available in a single unit system, while vernier calipers can display values in both mm and inch.
Here is a chart comparing these three types of calipers briefly, and please note the description is based on the general situation, not the absolute result. The vernier, dial and digital calipers are functionally identical, but the significant difference is the way of reading the result or working principle.
Which type of caliper measuring tool should you choose? Each type of caliper has its pros and cons. For example, the biggest advantage of the vernier caliper is its affordability and durability, you can buy it at a low cost and use it in most conditions, without a power source. If you want to obtain the most accurate results and require high efficiency, then digital calipers would be the best choice for you. Some models even have the data output function and memory features. Dial calipers also have fewer limitations than digital types but are easier to use than vernier types.