Snap Gages are among the oldest and simplest of all gages. As a general rule, snap gages should be used whenever possible where external measurements of diameters or widths of part are required. The first type of snap gage was the fixed or limit snap gage. These snap gages had limited adjustability and could only confirm that a part was within tolerance, but could offer no variable data.
Dorsey snap gages check the same conditions measured by a conventional OD checks. However, snap gages completely eliminate operator feel, and are much faster and more accurate. These gages have stronger contact pressure than most gages, and larger contact area. Contacts have carbide inserts for wear resistance and are lapped flat and parallel. Snap gages have adjustable back stops which stop the gage at the maximum diameter of the part. No rocking of the gage is required.
Snap Gage Features:
- Overloading the gaging anvil won't damage the indicator
- Reading is instantaneous
- Accuracy is not lost in the mechanism
- Adjustment is simple and positive
- Anvils are carbide for long wear
- Maintenance is economical due to simple design
- Settings are achieved with standard set master
Snap Gage Models
Modern Snap Gages
Today’s adjustable dial snap gages offer flexibility and accuracy. Most dial snap gages have 1" (25mm) of adjustment and can be quickly and easily set to any size within that range. Variable data is accomplished by the use of a dial or digital indicator, or LVDT.
Snap gages advantage
The main advantage of dial snap gages is that accurate measurements are not dependent on operator skill or a sense of feel as is true with a micrometer. The snap gages are literally "snapped" on to the part and a reading can be taken in a matter of seconds. A wide variety of snap gages anvils are available to check OD grooves, and other special shapes.
Snap gages designs
Snap gages are made in different designs with regard to indicator's measuring range, its accuracy and smallest graduation of the dial. A typical snap gage consist of a C-frame with gaging members in the jaw of the frame.