Snap gages are among the oldest and simplest measuring instruments. They are used to measure the outside diameter of round parts such as shafts and the thickness of many other components. The first type snap gages were fixed limit gages which only confirmed the part being measured was within its size limits. The gage had two anvil sets with the first set sized to the largest acceptable size and the other set to the minor size tolerance. Fixed limit gages do not supply any variable data such as, actual size, approaching tolerance limits and data feedback.
Today’s snap gages are more accurate and sophisticated. Dorsey offers many varieties of snap, outside diameter, thickness and length instruments. All can be supplied with a variety of contacts that allow these gages to measure different part configurations. Examples include blade contacts to measure O.D. groove diameters, roll and ball contacts to measure pitch diameters, concave anvils to check the O.D. of an interrupted or segmented part and other contact types, purpose built, for other applications such as spheres, lengths and widths. Dorsey’s family of snap gage products include the Dorsey / Standard SSG series, the SDN series, the LRS (long range snaps), the ‘Versatile” snap, the “Jaw” gage, the BC series universal I.D / O.D. bench comparators and traditional fixed limit snaps.
Again, all of these instruments (except fixed limit snaps) can be used with the Dorsey family of “High Amplification” and “Traditional” dial indicators, electronic or digital indicating devices.