We are offering rebar coupler and bar threading service at site in delhi national cutting tools are suppliers of concrete reinforcing materials to the construction industry rebar upsetting technology: cutting: 1) the end of the reinforcement bars is swan square. cold forging: 2) with the help of patented cold forging, the swan end of the reinforcing bar is then enlarged. With this the core diameter of the bar is increased to pre determined diameter. Threading: 3) an iso standard metric thread is then cut