Общий каталог FANAR 2021 - страница 292

Technical information i 4.8. Classes of Machine Taps The machine taps presented in our catalog are made in the basic class, intended for the most commonly used internal thread tolerances, appropriate for the particular thread types: for metric thread 6H, for unified thread UNC, UNF - 2B, for Whitworth thread BSW, BSF - "normal.” Per individual request we can manufacture the taps in other classes.Tap classes (ie. the tolerance field of a working segment) for metric threads are unified by international and national standards. A particular class of the tap threads allow for two or three fields of tolerance (see drawing and table below.) Metric internal thread [µm] Tap Forming Tap 8G 8G 8H 8H 7G 7G 7H 7H 6G 6G 5G 6H 5G 6H 7GX 5H 4G 7GX 5H 4G 6GX 4H 6GX 7G 4H 6HX 6HX 6G 4HX 4HX 6H 4H D2 d2 Threading die 4h Key 4h 6g 6H tolerance field of internal thread pitch diameter 6e tolerance field of external thread pitch 6g diameter 8e 6g 6e 6HX tolerance field of tap/forming tap 6g threading die tolerance field 8e According to Tolerance field of internal thread DIN 802 4H 4H 5H - - - 6H 4G 5G 6H - - 6G - - 6G 7H 8H 7G* - - - 7G 8G *DIN 802 provides the possibility of correction the tap tolerance comparing to the standard demands in case when it is required by the particular machining conditions, e.g. the sort of machining material. In such situation the symbol of the tap’s class with the sign “X”, e.g. 6HX, 6GX is obligatory. 12 289