Using a digital caliper for measuring critical dimensions and clearances is a quick and easy way to help in many situations a person may encounter when working on a car. The digital caliper fills the need in many cases much quicker than using a micrometer. Micrometers were at one time the go to tool for checking shaft sizes, bearing sizes, shim thicknesses and many other measurements that require precision down to a thousandth of an inch. Of course micrometers are now easier to use as technology evolves and digital micrometers are available.
Micrometers range widely in price. Starret Micrometers are at the high end professional machinist level. Fowler Micrometers or Mitutoyo Micrometers fit the needs of a professional repair shop, while for the home mechainic, an Anytime Tools Micrometer Set might suffice.
A good precision micrometer set for the enthusiast level mechanic is the Fowler electronic set.
. Also consider the non electronic Fowler set which still has a mechanical digital readout .
One drawback with the micrometer vs the digital caliper is that for measuring inside dimensions you will need a set of snap gauges. You must gauge the inside dimension and then measure that with the micrometer. Another consideration is that these instruments come with a standard which is used to calibrate them before use. In comparison, a zero button or absolute origin feature is used on the digital caliper.
A big advantage of using a digital caliper is that it instantly switches between fractional, decimal, or metric readings. Additionally it is calibrated to zero with the touch of a button. You can also measure outside or inside or step dimensions with one tool and one movement. The accuracy is very precise and in most instances it fills the requirement to get the information you need.
What Is a Digital Caliper?
A digital caliper is a tool that provides precision measurements of space clearances or objects. The device uses a set of jaws with a beam and a depth probe, with one jaw sliding and the other fixed to the bean. As the jaws are opened or closed, the moving jaw travels on the scaled beam working as a mechanical gauge. During this process a digital readout of the space between the jaws is displayed. Most digital calipers provide standard and metric measurements, changing between them with a switch. The electronic digital readout reduces errors and is much easier to read, than the dial type calipers. They are also easier and faster than the mechanical calipers.
A digital caliper makes precise measurement a snap. It is used to quickly measure the bore and exterior surface of a seal or bearing to assure getting the right part. You can also measure the bore of the component that seal the seats in. It can be used to measure the shaft that the seal or bearing rides on. These can be measured if the seal or bearing is damaged and distorted. Digital calipers be used to measure brake rotor thickness, snap ring thickness, belt thickness.
The uses are limitless. For example I have had torque converters slide out while removing an engine. Use the depth/step probe on a digital caliper to assure the converter is seated properly. Measure bolt lengths can be quickly and easily. In addition, checking the thread depth of the bolt hole to assure you don’t use a bolt that is too long. The accuracy is precise enough to measure bearing shell thickness to verify proper clearances.
Professional Digital Calipers
As in almost any automotive tool, three is a wide range of choices when buying a digital caliper. They are available as little as $8.00 for home use and hobbies to over $250.00 for the most accurate precision devices.
For the professional or machinist requiring absolute precision accuracy and durability, again Starret offers the best available. While being at the highest price point, it cannot be beat in terms of quality. The Starret has an 8 inch (200mm) range and accuracy to +/- 0.001″ and meets the DIN 832 international standard for linear accuracy.
Mitutoyo is an excellent choice for a serious enthusiast of professional mechanic that wants precision accuracy at a reasonable price. It has a 6″ (150mm) range and is waterproof. Mitutoyo is well known for it’s precision accuracy and has established an excellent reputation in the automotive field. Coming in at $125.00 this is the choice for the professional and serious enthusiast level mechanic. This instrument has proven itself in the industry and can be trusted.
Fowler offers a great choice for home, DIY enthusiast mechanics. As with the micrometers, Fowler gets the recommendation for auto enthusiasts, as well as home mechanics and professional use. The reliability, accuracy, and durability at an affordable price makes it the clear winner in this category. Measurement accuracy is given at 0.001″ (.02mm). It is constructed with a hardened stainless steel frame by an American company. The LCD screen is easy to read. While this tool has a 6 inch (150mm) range, Fowler High Precision does offer a 12 inch (300mm) version if you need more range. Although the Fowler model does not offer fractional readout, I find it is much easier to use decimal readings and a decimal/fractional chart to determine fractional measurement. The fractional measurements often come in a an unrecognizable reading and can be useless.
For the home mechanic that needs a basic digital caliper there are some good choices ranging from just under $20.00 to $50.00. Neiko has a very popular 6 inch model for under $20 and offers others in 8 inch and 12 inch. iGaging is another very popular caliper among the home mechanic and DIY crowd. There are comparisons between iGaging Mitutoyo as being similar with the absolute origin feature. It also is available in 6 inch, 8 inch, and 12 inch.
Whatever level of interest you have win cars, you will find using a digital caliper to be helpful. They are easy to use and are available in a price point to for your budget and needs. While uses are limitless, the confidence that you are using the part that fits more than justifies the expense of owning one of these instruments.
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