Dormer circular split dies can be used by hand or machine. Because the die has a split it can be adjusted slightly to provide a thread slightly smaller or larger than the norm. Metric Coarse Adjustable Dies. Application: For production of external threads less than three times diameter in length. Also available in MF, UNC, G(BSPF) thread forms. Tolerance: 6g Adjustable.Chamfer Lead: Two Threads.Surface treatment: Bright.Material: HSS - High Speed Steel. BS1127:1950Thread: 6mm x 1.00.Diameter: 13/16 in.