These British manufactured Carbon Steel Cut Threading Die Nuts have a machined lead-in for ease of use and accurate thread cutting. A Die Nut does not require a 'Die-Holder' and is normally used "free-hand" with a spanner. Die Nut's are normally used for thread cleaning/restoring and not for producing a 'new threads'.
B.S.F. Carbon Steel Die Nuts (3/16" - 5/8")