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Taps and Dies


 

Taps and Dies are used to put threads either on the inside of a hole or on the outside of a rod. 

This sheet describes the procedure for tapping a hole and using a die to make threads by hand on a part.

Controls: The controls when using taps and dies are as follows. 

  • Correct tap or die selection
  • Feeds and speeds
  • Tool condition and surface condition 
  • Tap Wrenches which are used to hold the taps by the square and to manually thread the part.
  • Die Wrenches which are used to hold the dies by there hexagonal shape and are used to manually thread the part.

Note: Note when using taps and dies in machinery there may be many more controls. 

        Operation: Tapping a hole 

  1. Drill a hole 
  2. Use tap/drill size chart to choose the correct the right tap
  3. Use oil to lubricate while tapping.
  4. Put the tap into the tap wrench
  5. Insert the tap into the hole.
  6. Apply some pressure on the handle of the wrench.
  7. Slowly turn the tap in a clockwise direction. 
  8. Once tap begins cutting the metal and making threads it will become hard to turn the tap. Back the tap off 1/4 turn or until you hear the metal chip break. 
  9. Continue feeding the tap into the hole and after every 1/2 turn back off 1/4 turn to break the metal chip. Once all the way through back the tap out in a counter clockwise direction until the tap is removed form the hole.
  10. Once all the way out, the process if complete. 


    Operation: Using a die
     

  11. First you must chose the correct die for the size diameter rod. Use a chart if necessary.
  12. Use oil to lubricate during cutting operation.
  13. Put the die into the die wrench
  14. put the die on the end of the rod that you want to make threads on.
  15. Apply some pressure to the handle of the wrench.
  16. Begin turning the wrench in a clockwise direction.
  17. Once the die begins cutting the metal and make threads it will become hard to turn. 
  18. Use the same process as the tap to break the metal away from the die.
  19. Thread the rod as far as needed then back the die all the way off, by turning the wrench in a counter clockwise direction.

Note: There are several other operations that can be done using taps and dies. This is just for basic operations. 
 

Trouble shooting: Some helpful hints when using taps and dies.

  •  Taps-
    Breakage:
    Incorrect Tap Selection
    Excessive Tapping Torque
    Operating Conditions
    Tool Conditions

    Chipping:
    Incorrect Tap Selection
    Operating Conditions

    Wear:
    Incorrect Tap Selection
    Operating Conditions
    Tool Conditions

    Undersize Pitch Diameter:
    Incorrect Tap
    Damaged Threads

    Torn or Rough Threads:
    Chamfer Too Short
    Wrong Chamfer Angle
    Galling
    Chip Packing

    Dies-
    The same applies for dies, correct selection and tool condition is essential to good operation.
     
     
     

Safety practices: Because of potential hazards the following safety rules must be followed: 

  • Always wear safety glasses when doing an operation. 
  • Pinching could occur if skin got between the tap or die during an operation.
  • Taps and Dies are very sharp so use care when handling them so that you don't cut yourself. 

Note: Many more safety practices would have to be taken if using taps and dies mechanically. Since we are using them manually by hand there is little hazard. 

References:

 Graham, Gregory S. (1981). Metalworking: An Introduction. American Technical Publishers, Inc. Alsip, IL.

http://www.regalcuttingtools.com
. 

ITT 252 - Materials Processing 
Department of Technology 
University of Southern Maine 
Prepared by Robert Owens, 12-12-02