Automatic Centre Punch


Pointeau a dispositif de frappe incorpore /Granetes automatico /Automatischer Körner


  • Manufactured from high-quality carbon steel.
  • Used for marking the centre point of the hole to be drilled, preventing the drill bit from skidding on the surface of the workpiece thus enabling a smooth and clean operation.
  • Easily replaceable pins hardened and tempered to 45-52 HRC for optimal durability.
  • In-built spring mechanism eliminates the need for a hammer
  • The depth of the indentation can be adjusted by simply rotating the cap.
  • Knurled body for firm gripping.
  • Available in a steel body, brass body and heavy duty.
Automatic Centre Punch
Automatic Centre Punch

50 HRC

Carbon Steel/ Brass body


How does an Automatic Centre Punch work?

An automatic centre punch unlike its conventional counterpart (the ordinary centre punch) doesn't require a hammer to strike. It can be pushed single-handedly against the surface that needs to be marked. The springs amplify and transfer the force thus creating the desired indent. The mechanism consists of:

  • a weight
  • an intermediate pin
  • a punch pin 
  • a cap
  • and the housing/ body

At the equilibrium position both the springs neither undergo compression or tension and are thus at a stable state. The intermediate pin tends to incline away from the pocket inside the weight.

Once a force is applied onto the punch against a rigid surface, the surface tends to push the punch's pin back into its housing. The pin further pushes onto the intermediate pin upwards which in turn pushes the weight against the heavy spring. The spring now compressed is removed from its stable state.

As the intermediate pin is further pushed upwards it gets aligned straight as the slope on the pin meshes against the inner groove of the body. The intermediate pin gets pushed inside the pocket in the hung weight eliminating the contact between the pin and the weight. This removes any compression force acting on the heavy spring. The spring tends to achieve its equilibrium state by pushing the weight against the pin. The force is eventually transferred to the punch pin which pushes into the surface thus creating a recess in it.

 

 

 

Adjusting the force

 

 

As the cap of the punch is loosened, more space is created at the back of the punch. This allows the intermediate pin to retract a larger distance before it starts to compress the spring leading to a comparitively lower build up of force inside the spring. Once the pin enters the weight's pocket the spring exerts back this decreased force which is eventually transferred to the punch pin and then to the surface. This reduces the intensity of the strike of the punch and the depth of the recess. Similarly tightening the cap allows higher intensity strikes and deeper indents.

C.no Description Size Action
    inch mm  
ACP Black body 5 125
ACP-BR Brass body 5 125