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Tap Drill Chart Metric Tap Drill Chart Tap Speed Chart Table 302 303

 

FACTORS THAT DETERMINE TAPPING SPEED
Appropriate tapping speeds are determined by the following factors: Material to be tapped, hole depth (through or blind), depth of thread, thread pitch, percentage of thread, lubrication, machine equipment, and whether tapping is to be horizontal or vertical.

DETERMINING SPEEDS
Speeds, tap drill sizes and thread percentages can be calculated using tables below.

Speeds my be INCREASED under the following conditions: When using a spiral point, when percentage of thread decreases, when quality and quantity of coolant improves, and when thread pitch gets finer.

Speed MUST be DECREASED under the following conditions: When thread depth increases, when using bottom taps, when using coarser thread taps, when running tapered (by ¹/₄ to ¹/₂), when using pipe taps, and when quality and quantity of coolant is restricted.

TAPPING SPEED GUIDE
FACTORS TO BE CONSIDERED WHEN DETERMINING TAPPING SPEED: Material to be Tapped Hole Depth (through or blind) Depth of Thread Thread Pitch Percentage of Thread Lubrication Machine Equipment Horizontal or Vertical Tapping SPEEDS MAY BE INCREASED: When using a Spiral Point As the Percentage of Thread Decreases As the Quality and Quantity of Coolant Lubricant Improves As You go to Finer Pitch Threads SPEEDS MUST BE DECREASED: When Thread Depth Increases When Using Bottom Taps When Using Coarser Thread Taps By 1/4 to 1/2 When Running Tapered Pipe Taps When The Quality and Quantity of Coolant or Lubricant is Restricted RPM =      SFM      .26 X TAP O.D.   To use this formula for Metric, convertMetric to Inch Equivalent by multiplyingMetric sizes times .03937	MATERIAL	SPEED FEET PER MINUTE
	Aluminum Alloys 90-100 Brass 60-100 Bronze 40-60 Cast Iron:   Ductile, Annealed 60 Ductile, as Cast 30 Ductile, Tempered 15-20 Gray, Annealed 80 Gray, as Cast 35-60 Malleable 60 Malleable, Heat Treated 25-50 Copper 40-60 Magnesium Alloys, Annealed 175 Monel, Annealed 20 Nickel Alloys, Annealed 25 Plastics:   Thermo 50 Thermosetting 50 Steel:   Carbon (Low) 40-60 Carbon (High) 25-35 Cast 20-45 Chromium 10-45 Cobalt 10-45 Free Cutting 50-80 Hardened 10-25 Leaded 45-60 Manganese 10-35 Molybdenum 10-35 Nickel 10-35 Tool 10-25 Vanadium 10-35 Stainless Steel 10-35 Prec. Hardening 10-25 Sintered Metal 50-70 High Temperature Alloys:   Titanium 10-40 Inconel 5-15 Hastalloy 5-15 Rene 41 5-15 Waspaloy 5-15 Zinc Die Cast 100-150