Blind Hole Tapping With A Magnetic Drill – Expert Solution For Tapping.

Blind Hole Tapping or also called as Blind Hole Thread Cutting With A Magnetic Drilling Machine.

Tapping through holes or making threads in a through holes is a pretty easy task with a magnetic drill or a conventional drilling / tapping machine. But tapping blind hole is a completely different story.

General problems in blind hole tapping with a magnetic drill or a conventional drilling machine?

  1. The depth of the hole is unknown,
  2. Suitable taps are not available,
  3. The wrong type of taps are used,
  4. Tap gets stuck in the hole,
  5. The tap cannot be removed from the other end due to blind hole,
  6. Breakage of taps, etc.

The solution for blind hole tapping:

With below 10 steps one can now easily tap blind holes. Let’s consider an example of making M24 (15/16 inches) size thread or tap in a blind hole.

Summary of tools needed: 1x Magnetic Drilling Machine, 1x Twist Drill, 1x Tap, 1x Tapping adapter chuck, 1x Tapping adapter insert and 1x Cutting paste.


  1. You will need an M24 (15/16 inches) tapping capacity magnetic drill or a conventional drilling machine, with REVERSIBLE MOTOR, also called as CW/CCW Motor. All the ProfiPLUS class machines of BDS Maschinen GmbH have a reversible motor.

  2. To make a thread of M24 (15/16 inches), we need to make a blind hole of 21.00 mm (13/16 inches) diameter with a conventional twist drill bit. An annular cutter cannot be used for drilling blind holes.

  3. After drilling the blind hole, remove the drill bit from the machine and insert a GSW Quick change drill chuck. In this case, we will need GSW 333.  Insert the quick change drill chuck in the machine arbor replacing the drill bit.

  4. We will also need GSS Quick change insert with safety friction clutch. In this case, we will need GSS 322. Insert the insert in the drill chuck.

  5. For making M24 thread we will need a M24 size ”machine” tap. Insert the tap in the quick change insert.

  6. Apply Cutting Paste to the Tap.

  7. Now, put the magnetic drilling machine in the first gear, keep the RPM to minimum, keep the torque to maximum and start giving feed.

  8. The Tap takes the travels and goes into the hole creating threads.

  9. Once the tap head reached the bottom of the blind hole, the friction clutch of the Quick change insert will get activated and the Tap will stop to penetrate more. Thus, the tap does not break.

  10. Now give the reverse feed to the machine and remove the Tap out of the hole. This process does not damage the thread made.


This is the easiest, fastest and safest way of making blind hole tapping with a magnetic drilling machine. For more information please contact our technical team at


GSW Quick change drill chuck
GSW Quick change drill chuck

GSS Quick change insert with safety friction clutch

GSS Quick change insert with safety friction clutch



Review BDS Machines