How to select suitable tapping speed for your tapping machine?

HIGH PERFORMANCE TAPS RECOMMENDATION SPEED AND FEED CHART

Tapping speeds are determined by many factors. The main ones are:-

1)TappingThread pitch

2) TappingMaterial being tapped

3) Tapping Hole depth

4) Tapping Hole type, through or blind

5) Tapping Depth of thread

6) Tapping Lubricant quality and flow rate

Tapping speeds can be calculated with:- RPM = Feed speed (SFM) /0.26 x Tap OD

Recommended SFM chart are given as below

With so many factors affecting tapping speeds there may need to be some experimentation to find the ideal. One suggestion is to start at the slowest speed and work up.

Tapping speeds should be decreased if :-

1) Tapping Lubricant is poor, or flow is restricted

2) Tapping Bottom lead or Spiral flute taps are used

3) Tapping Thread depth (%) increases.

4) Tapping Thread pitch is coarse

5) Tapping Cutting taper threads (50% normal speed)

6) Tapping Cutting Acme or Trapezoidal threads (40% normal speed)

Tapping speeds can be increased if:-

1) Tapping Thread depth decreases

2) Tapping Thread pitch is fine

3) Tapping Coolant flow and quality is good

4) Tapping Spiral point taps are used