Version:
The short shank overhangs less and hence is more stable.
Application:
For use as machine tap or for cleaning existing threads by hand. Tapered Whitworth pipe thread (BSPT) to ISO 7/1 and BS21, for joints with sealant in the thread. See the table for the specified minimum size of the tapping hole.
Recommendation:
Tapping hole ⌀ A:Pre-drill a plain hole
without using a reamer. Variant A can be used if there is no risk of sealing problems.
Tapping hole ⌀ B:Pre-drill a plain hole and then
ream it using a 1:16 taper reamer (see No. 162650). The taper bore ⌀ can then be checked laterally by reference to the D
max check dimension (see table).
Variant B for drilling the tapping hole offers the best process reliability for the tapping operation and at the same time ensures the most reliable seal in the thread.