Need to remove broken drills or taps without damaging the work-piece?

The annoyance of breaking a tap is usually only beaten by the frustration of trying to remove it from the job - as all machinists can attest.

Broken taps are typically caused by a variety of issues:

• Tap out of alignment or not running true
• Core hole too small
• Incorrect tap for the material
• Chamfer lead too short
• Incorrect sharpening
• Tap hitting bottom of a blind hole
• Tap reversed carelesly
• Lubrication lacking or wrong quality
• Material too hard or abrasive for the type of tap
• Speed too fast
• Tap requires resharpening
• Tap Flutes blocked with swarf
• Hole diameter changes (if punched not drilled) 
• Excessive torque applied

(see www.tap-die.com for more details)

As all good machinists know, the best solution is prevention:

• Ensure the job is set up properly
• Taps are brittle - handle with care
• Ensure correct hole size is drilled
• Lubricate
• Break up the chips

Even so, doing everything right, these things still happen.

Now what?  The tapping is typically one of the final operations on the work-piece.  Do you, as the production manager, now write off the job along with the cost of the labour, the machining operation, not to mention the material costs and simply make another part?

Besides the smallest and most simplest of parts, this is typically a very uneconomic solution.  Not to mention the delays your customer will now experience due to the repeated manufacturing of the part.

Do you attempt to remove the tap using conventional means and risk damaging the work-piece?  As the taps are very hard, it is very difficult to machine them using traditional means often taking longer and causing damage to the work-piece that then requires additional operations to repair.

Our answer?  The eromobil!  Spark Erosion (or Electrical Discharge Machining) of the broken tap.  

A skilled operator uses a hollow copper electrode and an electrical discharge to remove the core of the tap.  The tap can then be easily removed with a small chisel and tweezers.

ASAP Power is the proud agent of German built eromobil from Handling Tech for Australia and New Zealand.

For more information on the eromobil visit our website

The eromobil is available for sale and hire depending on your needs.

Contact me today, to discuss your requirements.

[email protected]