BS 3409-1:1961

This standard BS 3409-1:1961 Specification for the tapping of holes to receive wire thread inserts (UNC and UNF threads) is classified in these ICS categories:

• 25.100.50 Taps and threading dies

This British Standard comprises three sections:

Section 1, which specifies limits of size for tapped holes to accommodate wire thread inserts to provide thread sizes from 1/4 in to 11/2 in UNC inclusive and from 1/4 in to 1 in UNF inclusive;

Section 2, which recommends screwing taps intended to produce holes to the limits of size specified in Section 1;

Section 3, which gives a recommended gauging system for checking the tapped holes.

Specifies limits of size for tapped holes to accommodate wire thread inserts to provide thread sizes from ¼ in to 1½ in UNC inclusive and from ¼ in to 1 in UNF inclusive. It includes recommendations for general dimensions and limits of size on the threaded portion of screwing taps intended to produce holes to the limits specified, together with details of a recommended gauging system for checking them.