WIDIA - Полный каталог инструмента - 2017
для размещения заказа - zakaz@widiahanita.ru
Technical Information
Tolerances Over Basic Pitch Diameter
Internal Unied Thread
2B
3B
For the tap user’s convenience, new
generation WIDIA-GTD™ taps are sized
for the intended class of fit of the internal
screw thread. ISO standard 2857 specifies
the manufacturing tolerances of the tap
pitch diameters for ISO metric threads of
tolerances classes 4H to 8H and 4G to 6G.
Examples:
4H tap corresponds to ISO 1
6H tap corresponds to ISO 2
6G tap corresponds to ISO 3
Similarly, ASME B1.1 recommends tap pitch
diameter tolerances for 1B, 2B, and 3B
classes of fit.
However, it is recognised in many
1B tapping applications that taps should
have a pitch diameter that is larger than
industry standards. These applications
include tapping abrasive materials or
CNC applications where machine and
tool concentricity is excellent. Taps
manufactured to WIDIA™ standards are
designated with an X after the class of
fit (example 6HX or 3BX). These graphs
illustrate the differences.
Internal Metric Thread
nominal pitch diameter (basis)
6H
4H
7G
6G
nominal pitch diameter (basis)
zakaz@widiahanita.ru
www.widiahanita.ru
Y99