Using a Hand Tap

A hand tap is a tool used to cut internal threads into a drilled hole so that a screw or bolt can be directly fastened into material such as aluminum. 

 

 Before Tapping 

 

 Drill the correct tap drill size hole (example: #21 for 10-32, #7 for 1/4-20) 

 Deburr the hole to remove sharp edges 

 Secure the part so it cannot move 

 Select the correct tap size 

 

 

 How to Use a Hand Tap 

 

 Insert the tap into a tap handle 

 Align the tap perpendicular to the hole 

 Apply gentle downward pressure and begin turning clockwise 

 After 1–2 turns, continue turning slowly with steady pressure 

 Every few turns, reverse slightly to break chips 

 Continue until the desired thread depth is reached 

 

 

 Key Technique 

 

 Keep the tap straight at all times 

 Do not force the tap if it becomes difficult to turn 

 Use cutting fluid when possible to reduce friction and improve thread quality 

 

 

 Common Mistakes 

 

 Starting the tap at an angle 

 Forcing the tap (can break it easily) 

 Not backing out to clear chips 

 Using the wrong tap drill size 

 

 

 Key Idea 

 A hand tap must be started carefully and kept straight. Most tap failures come from misalignment or forcing the tool instead of allowing it to cut gradually.