Hand Tap High Speed Steel 3/8" BSCY (26tpi)

Product Description

26 tpi

60 degree thread angle.

UN thread form

Available in 3 leads:

Taper: 8 - 10 leads of thread used for starting new threads

Intermediate:  Less tapered, 4 - 5 leads,  used to follow a Taper tap or for restoring threads

Bottoming: Very little taper 1 1/2 - 2 1/2 leads, so will cut a new thread to the bottom of a blind hole, but the lack of taper makes starting a new thread difficult.

UN (Unified National) thread form

These taps are ground to the Unfied/Metric 60 degree thread form which makes it essentially the same as the original BSCY thread form.

For the purest the thread crest and root form is truncated (flat) where as the British Standard specifies a rounded crest and root.

Use of a lubricant is necessary on most tapping operations.