Use recommended tapping drill 
                    (ream for consistency).

 Select the correct tap, i.e., taper, 
                    plug, spiral point, etc.

 Use a pitch controlled tapping attachment. 

 Choose speed to suit conditions.

 Check for true alignment.

 Use the recommended lubricant.

 Keep the tap sharp, regrind by machine only.

 Check material for hardness periodically.

 Check gages for wear.