END MILL PRICELIST EFFECTIVE 9/1/24

L-and-I-button
TECHNICAL DATA
Taps & Dies

Glossary of Terms
Speeds Information
Speeds For Inch Taps
Speeds For Metric Taps
Minor Diameters of Tap Holes
Main Tech Menu

Speeds Information

Tapping speeds not only affect productivity, but they can influence the tap life and the part quality. The feed of a tap cannot be varied independently as can be done with other cutting tools. The tap feed is fixed by the number of threads per inch or the lead of the tap threads.

Excessive speed can cause early tap failure due to the high temperature. Also, failure can be accelerated due to the welding of small particles of the workpiece material to the tap surfaces. Factors to be considered when determining the best tapping speed are the following:

  1. Type of material to be tapped
  2. Hardness of material to be tapped
  3. Length or depth of hole
  4. Whether through or blind hole
  5. Length of tap chamfer
  6. Lead of the thread
  7. Tapping fluid used
  8. Condition and type of machine
  9. Percentage of thread to be cut

The tabulated recommended tapping speeds should be modified for the following:

  • Speeds may have to be lowered as the length of hole increases, owing to the
    accumulation of chips that increase friction and interfere with lubrication.
  • Speeds can be increased when using spiral point, spiral flute, or forming taps.
  • Speeds should be decreased when using bottoming taps.
  • Speeds can be increased as the percentage of thread is decreased.
  • Speeds should be decreased for coarse thread taps.
  • Taper pipe taps should be run at between one-half and three-quarters the speed
    of a comparable tap of the same diameter and pitch.
  • The quantity and quality of tapping fluids may affect the tapping speed significantly.

The recommended peripheral speeds shown in the following table are only starting points.

Material Speed in feet
per minute (fpm)
Aluminum 50 - 150
Aluminum Bronze 20 - 80
Brass 50 - 200
Bronze 50 - 100
Cast iron 50 - 100
Copper 30 - 60
Fiber 80 - 90
Magnesium 75 - 200
Malleable Iron 35 - 60
Monel Metal 20 - 40
Plastic - thermoplastic 50 - 100
Plastic - thermosetting 50 - 100
Steel - free machining 40 - 80
Stainless steel 5 - 35
Titanium alloys 10 - 40
Zinc die casting 60 - 150