Technical Information for Thread Milling Technical Information for Thread Milling Tool Selection For indexable and solid carbide Mill Threads The following chart provides a fairly accurate visual selection tool for Internal Threading. The chart is suitable for the following thread forms: ISO, UN, WHIT, NPT, NPTF, BSPT and PG. Conversion of Cutting Speed to P=Thread Pitch A Rotational SpeedConversion of selected cutting speed to rotationalNspeed is calculated by the following formula:Example: v=120 m/minD=30 mmVx 1000120 x 1000VN==1274 RPMVDJT x D3.14 x 30D=Cutting diameterTPI mm45686.05.04.03.53.01m D= Tool cutting diameter00D=21D=29 10 2.5122.0 0" 1 108 O Q o Internal Thread External Thread 16 1.5201.25241.0 D=9 D=12 u 32 0.75 3 48 0.5 090 Left Hand Right Hand Left Hand Thread Thread Thread mm 4 5 6 7 8 9 10 11 12 13 14 15 16 18 20 22 24 26 28 30 32 34 36 38 40 44 48 52 58 64 ¥ §8