Tools & Gear Taps & Dies Chrome Alloy Button Dies and Die Nuts

4838-2 2" x 4.5 BSW Chrome Die Nut British Standard Whitworth (BSW). Die nuts are commonly used when a button die is not suited due to work space restrictions and / or on site thread accessibility. They can be used as thread chasers to clean an existing thread. They can also be used to create a new male thread on non-ferrous metals and plastics. Chrome alloy dies are not suitable for creating precision, safety or critical threads. The BSW thread form was developed by Sir Joseph Whitworth in 1841. The thread form has rounded roots and crests and is specified in BS84:1956. The thread angle for BSW is 55° as opposed to 60° in Metric and Unified threads.