To determine final setting time

-steps:

1. Fiz a 1mm square needle fitted with a metal attachement hollowed out to leave a curcular cutting edge
2. Gently lowered needle to surface of cement
3. When needle make an impression on cement but circular cutting edge does not , final set has taken place
4. Final setting time is taken from the moment water was added to cement
5. Not more than 10 hour for OPC