THREAD SETTING PLUG GAGES

Thread setting plugs are to be used to set ring gages only. Their purpose is setting or re-setting the ring gages and determining if the ring is within tolerance. Setting plugs are not to be used to check the work piece.

To insure the ring gage is still within its tolerance after being put into use, the setting plug gage, both GO and NOGO, should be used to verify accuracy. This also provides the gage user the capability to reset the ring gage as required. Generally, the setting plug is ordered at the same time as the thread ring gage and there could be a cost savings when ordering them together. Remember, the set plug gage is needed in the manufacturing and certification of the ring gage and they are matched to each other and meant to be a metal to metal fit. If not set together they most likely will not fit together without re-setting the ring gage.

n setting an adjustable thread ring gage, the sealing compound must be removed and the locking screw loosened. Turning the adjusting screw to the right enlarges the ring so that it turns freely onto the thread setting plug. Alternately adjusting the adjusting screw and tightening the locking screw, until a firm fit on the threads is achieved, is the proper method of assuring accurate adjustment. More complete instructions.

A truncated setting plug of standard design will have the crest of the thread truncated for half the length of the gage, unless otherwise specified, giving a full-form portion and a truncated portion. In setting thread ring gages to size, the truncated portion controls the pitch diameter and the full-form portion assures that the proper clearance is provided at the major diameter of the ring gage. The use of the full-form portion along with the truncated portion checks the flank angle of the thread gage.