6. Recommended Tapping Speed

Tapping Speed

The following machining conditions aff ect tapping speed: kind of taps, workpieces, number of chamfered threads, materials, hole conditionand SP lubricant. It is necessary to select the suitable tapping speed by paying attention to these conditions. When work material has excellent workability, when there is a little depth of tapping, or when tapping lubricant can be sufficient, select rather higher tapping speed. When workability of work material is unknown, to be safe, try nearly the lowest tapping speed at fi rst, and then increase the speed gradually. Following speed is basically for the cutting condition under the use of cutting oil. In case of water soluble cutting oil, please reduce the speed by 30%.

SL

Workpiece MaterialsTapping Speed - Vc(m/min)
Spiral FlutedSpiral PointedRoll TapsStraight FlutedCemented Carbide
Low Carbon SteelsSt44, C10~C258~1510~208~156~10-
Medium Carbon SteelsC25~C456~128~147~125~9-
High Carbon SteelsC45~C585~108~125~105~8-
Alloy SteelsCrMo~NiCrMo5~107~105~105~8-
Thermal refi ned steels20~45HRC3~54~7-3~6-
Stainless SteelsAISI3~84~96~153~7-
Tool Steels1.2311, 1.23445~86~10-5~9-
Cast SteelsSC6~108~13-6~10-
Cast IronsGG---12~1715~25
Ductile Cast IronsGGG5~105~10-5~812~20
CoppersCu8~128~1325~357~1115~33
Brass · Brass CastingBs · BsC11~2213~2525~3510~2023~33
Phosphor Bronze · Phosphor Bronze CastingPB · PBC8~1510~1825~358~1518~33
Wrought AluminumAl15~2520~2525~3515~2023~40
Aluminum Alloy CastingsAlSi11~2212~2415~2510~2015~25
Magnesium Alloy CastingsMC7~1510~20-7~1512~20
Zinc Alloy DiecastingsZDC7~1510~2015~257~1512~20
Thermosetting PlasticBakelite (phenol-PF)11~1712~18-10~1515~25
Thermoplastic resinPVC, Nylon11~1712~18-10~1515~25
Titanium AlloysTi-6Al-AV etc6~96~8---
Nickel Base AlloysHastelloy, Inconel, Waspaloy3~63~6---
Formula Tapping Speed (Vc)Revolution per minute (n)
n : Revolutions per minute (min -1)Vc : TappingSpeed (m/min)
π : 3.14Dc : Nominal diameter of tap (mm)
Dc : Nominal diameter oftap (mm)π : 3.14

PO

LONG

EG (STI)

SPECIAL

THREADS,

GAUGES

DIES

CENTER

DRILLS