Abstract: A tapping attachment particularly adapted for use with machines under numerical computer control. The attachment embodies tension cushion for the spindle by way of a tension spring as well as compression cushion for the spindle. The compression cushion is provided by way of an adjustable spring member which is in a bore of the spindle and which has a helical spring formed in it. The tension spring is on the inside of the compression spring member. The attachment as a whole is of relatively short overall length, adapting it for use in an automated system wherein attachments are automatically inserted in the machine and interchanged. The attachment embodies a hard start feature provided by way of releasable securement which will release the spindle for movement in response to predetermined axial force, so that in the case of a dull tap the automated movement of the attachment under computer control will be kept accurately programmed.