BS 1660-4:1989

This standard BS 1660-4:1989 Machine tapers is classified in these ICS categories:

• 25.060.20 Dividing and tool-workpiece holding devices

This International Standard specifies the dimensions, in millimetres¹⁾, of 7/24 tapers for spindle noses and tool shanks and equipment for manual changing. It also specifies the external diameters of the collars for these tool shanks and equipment, and the positioning of the front face of the collar with respect to the taper in the case of attachment by the front face.

NOTE 1 The collars have two seatings on the periphery into which the two driving tenons on the machine spindle are fitted and are intended for the transmission of the spindle rotational movement to the tool or equipment.

NOTE 2 Shank attachment can be carried out either by conventional rear clamping, using a clamping fastener screwed on the rear side of the shank, or by front clamping of the collar using a locking device mounted on the machine spindle and applying the tool or equipment on to the spindle. Only in the latter case is it necessary for the positioning of the front face of the collar with respect to the taper gauge plane having the basic diameter D₁ to be accurately specified.

This type of taper is designed for various types of machine tool spindle noses as well as for the corresponding tool shanks and equipment.

The dimensions for tool shank tapers automatic changers are specified in ISO 7388-1.

¹⁾ The inch values will be determined after acceptance of the metric values.

Dimensions in millimetres of 7/24 tapers and equipment for manual changing. Specifies external diameter and position of front face of the collar with respect to the taper in the case of attachment by the front face.