Electronic Dial Bore Gage

It’s another one of those “necessary evils” that shopfloor employees often don’t appreciate the significance of. The so-called non-value-added operations often seem to be a hassle, but when they add to the quality of the product, who really can deny the value?

While gaging is an additional step in the production process, it is important in ensuring that a shop is meeting its required tolerances. It plays a significant role in determining the accuracy of a bored hole, and it can also help to predict remaining tool life through variations in tightness of the gage in the part. But the effectiveness of the gage is directly related to the operator’s ability to accurately read its display.

Sunnen Products now offers optional, large-readout electronic indicators on its entire range of dial bore gages. Highly visible in the shop environment and a quick reference for multitasking operators, the electronic dial bore gages feature precision indicators with 6-digit LCD readouts, 11-mm character height and three large buttons for easy operation. Capable of checking bore sizes from 0.054 inch (1.37 mm) to 12 inches (300 mm) and bore lengths as long as 24 inches (600 mm), the electronic bore gages allow users to set upper and lower tolerance limits for go/no-go judgments, which are then displayed in full-size characters. Standard analog indicator-equipped gages read out in tenths (0.002 mm); models with five-tenths (0.010 mm) readouts are also available. Operators can easily toggle between inch- and metric-measurement readouts. The gage is available in 34 different standard diameter/length ranges, as well as optional lengths.

The electronic indicator dial bore gages, accurate to ±0.00012 inch (±0.003 mm) with 0.00005 inch (0.001 mm) resolution, provide the ability to perform scaling calculations, judge tolerance, hold data and perform general comparison measurements. Internal calculations using a simple [F(x)=Ax)] formula are also possible. Using the formula requires mounting the indicator on a measuring jig, and setting the calculation factor (to any value) allows direct measurement without using a conversion table and improves measurement efficiency. This means that the indicator can be programmed with a conversion, and the bore ID is displayed rather than the amount the bore varies from perfect (zero on the display).

The company says the gages are ideal for shops honing production runs of parts that require SPC data at multiple points in the bore. Data output via an SPC cable enables direct transfer of bore measurements to a computer for use with SPC software. Optional wireless data export to a computer is also available. A transmitter is connected to the gage, and the receiver is connected to the computer. The transmission range is approximately 60 feet.

The indicator face displays the spindle’s actual position via an absolute linear encoder capable of relocating the origin, even after the power is turned off, for quick-start, multi-point measurement. The positive/negative count resulting from the spindle’s up-and-down movement can be toggled, and the indicator face can be rotated 330 degrees so it can be read at virtually any angle.

Gage centralizers are adjustable to ensure proper centralization over the entire diameter range, resulting in accurate centering action, even if the gage is tilted off the bore axis. A right angle attachment is available for conditions where the gage is difficult to read or total gage height is an issue. Blind hole probes and probe extensions are also available. Probe extensions are 2.5 inches (63.5 mm) long, and as many as three extensions can be assembled together.

Most models feature all-carbide gaging points for applications where exposure to extreme wear conditions, such as heavy production, rough workpieces or abrasive materials, is a factor. All dial bore gages are designed for the machining environment with a dust/water protection level of IP42 or IP53. Battery life, under normal use, is approximately 5,000 hours.

When bore quality assurance is required, it makes sense to use gages that make the job easier and repeatable.

Fast, Precise ID Measurement

Sunnen’s PG-Series bore gages take a different approach to gaging with a mechanical design and speedometer-type scale for quick visual confirmation of ID by a multitasking machine operator. This gage combines lab-precise accuracy (±0.000025 inch/0.0006 mm) with a shop-hardened design that’s compact, portable and mountable on machining stations. These gages need no electrical or air connections, making them immune to fluctuations in line voltage or air pressure. The bore gages remove complexity, skill and “feel” from the measurement process, allowing machine operators to precisely confirm part size with a visually intuitive analog scale. The mechanical design of these gages is not affected by temperature, moisture, air pressure or vibration.

PG gages can be used to examine the entire bore for diameter, taper, barrel, bell mouth, out-of-round and lobing. A sliding faceplate with adjustable stops permits end-to-end examination of bores. Stops can be set to allow examination of a particular section of the bore, with accuracy right up to the edge of ports, lands and ends. The speedometer-type scale provides readouts down to 0.000050 inch (0.001 mm) for 100-percent inspection of machining operations or fast sampling of large vendor lots. Various models are available for gaging IDs from 0.090 inch to 4.310 inches. Metric models cover IDs from 2.0 to 109.47 mm. A calibration ring traceable to NIST and international standards comes with the gage and features nominal size at 68°F marked on the face. Calibration checks with the ring ensure that gage-setting capability retains accuracy within original limits of ±0.000020 inch.