The 4 Best Digital Calipers on the Market
Vernier-dial-digital Caliper, a tool every engineer should own in their arsenal. The Vernier caliper uses the Vernier scale to precisely measure linearly. The scale is mechanically operated and is read by interpreting the physical location of the ‘tick’ marks on the moving part in relation to the fixed scale. A dial caliper uses a rack and pinion assembly to move a dial, taking the place of the sliding scale on the Vernier calipers. The dial shows the fractional value between each .1” ‘tick’ mark on the fixed scale in .001” increments. The scale is zeroed by rotating and locking the dial in a closed position such that the hand is pointing to the ‘0’ tick mark.
A digital caliper replaces the mechanical variable with electrical components to more accurately and reliably record measurements. As described by many websites and documents, the digital caliper uses an array of capacitors that move in and out of alignment as the slide moves along the fixed scale. The caliper generates accurate readings by digitally zeroing and then reading cyclical changes in capacitance as the array moves in and out of alignment. Because the digital caliper relies on an accurate reading of capacitance, metal dust and moisture can cause the reading to jump around.
The calipers shown below have been used in inspection, welding, machining, and engineering environments for approximately 1 year. The calipers were tested on calibrated master inspection blocks of .5000” and 4.0000” to determine whether accuracy changed at larger measurements. Each of these have exceeded expectations for accuracy after being subjected to their respective environments.
Each digital caliper, after being subjected to grinding dust, coolant splash, machining chips, and being handled by multiple people, has kept readings within .0005” of the target value. This means the calipers have not degenerated in accuracy at all with respect to the manufacturer’s given resolution and measurement accuracy numbers.
The water resistant and coolant proof digital calipers have not experienced any hiccups while operating in the field. The STI digital caliper, on multiple occasions, became dirty from grinding dust and began jumping around uncontrollably. After cleaning the caliper (blowing out using filtered shop air), the calipers began working like new again.
Ultimately, I highly recommend each of the following digital calipers.
Fowler 54-101-300-1 Digital Caliper
- 12”/300mm range
- +/- 0.001”/0.02mm reading accuracy
- 0.0005”/0.01mm resolution
- Stainless steel frame
- Inch/mm readings
- Includes case
Starrett 798 Water Resistant Digital Caliper
- +/- 0.001”/0.02mm reading accuracy (accuracy reduces to +/- .03mm at readings larger that 100mm)
- 0.0005”/0.01mm resolution
- IP67 protection against coolant, water, dirt, and dust
- Hardened stainless steel frame
- Inch/mm readings
- Includes case
Mitutoyo 500-752-20 Absolute Coolant Proof Digital Caliper
- 6”/150mm range
- +/- 0.001”/0.02mm reading accuracy
- 0.0005”/0.01mm resolution
- IP67 protection against coolant, water, dirt, and dust
- Inch/mm readings
- Includes case
SPI 13-612-7 Digital Caliper
- 12”/300mm range
- +/- 0.0016”/0.041mm reading accuracy
- 0.0005”/0.01mm resolution
- Stainless steel frame with carbide tipped jaws
- Inch/mm readings
- Includes case
Jarrett Linowes
Mechanical Engineer
omniamfg@gmail.com
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