A Q&A on Optimizing Die Guide Clearances for EDM Drilling Applications


Welcome back, EDMers! This Q&A post is designed to help inform you on the best die guide clearances for your specific EDM drilling needs and applications.

 Q: What are the typical die guide clearances that Makino recommends for EDM drilling applications?

A: Properly optimizing die guide clearances for specific EDM drilling applications significantly contributes to the overall success in machine shop drilling operations. If not done properly, shop owners can experience continual setback and operational challenges. For example, using a clearance that is too large can give way to poor part quality. On the other hand, using a clearance that is too tight can also result in poor edge quality and reduced tool life.

Makino offers two different types of EDM drilling machines designed for specific applications. Below are the recommended die guide clearances for each:

Fine-Hole EDM Drilling:

Fine-hole EDM drills are designed specifically for ultra-high accuracy. These machines use a standard EDM oil dielectric fluid, and all machining is performed fully submerged. Both standard sinker EDM and EDM drilling operations can be performed using fine-hole EDM drills. Due to high-accuracy requirements, die guide clearances are small and limited to L:D drilling ratios.

Some Makino products that support fine-hole EDM drilling are noted below:

  • EDAF2 / EDAF3 equipped with the fine-hole specification
  • EDGE2 / EDGE3 equipped with the fine-hole specification
  • EDFH-1 machine

Recommended fine-hole die guide clearances are listed below:

  • 0008″ ~ 0.012″ Ø à 0.0002″ clearance
  • 012″ ~ 0.080″ Ø à 0.0003″ clearance
  • 080″ ~ 0.160″ Ø à 0.0006″ clearance

Production EDM Hole Drilling:

Production EDM hole drills are designed primarily for high-speed and high-volume production, as the name implies. These machines use a deionized water dielectric fluid; and like fine-hole EDM drilling machines, all machining is also performed fully submerged. However, unlike fine-hole EDM drills, production EDM hole-drilling machines perform only EDM drilling operations and not standard sinker EDM operations. Due to more open part tolerance, die guide clearance is larger to prevent jamming of the electrode into the die guide on deep L:D ratio holes. Die guides are also available in long/extended lengths to yield deeper access to a workpiece.

Some Makino products that support production EDM hole drilling are noted below:

  • EDBV3
  • EDBV8

Recommended production EDM hole die guide clearances are listed below:

  • 008″ ~ 0.125″ Ø à 0.002″ clearance
  • 125″ ~ 0.250″ Ø à 0.004″ clearance


Knowing the proper die guide clearance recommendations for your precise EDM drilling applications helps shops not only improve machining performance but also preserve machine and tool life, both of which are guaranteed to deliver value to any machine shop in the long run.

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