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"Gun Feeder" Small Diameter & Deep Hole Gun Drill Machine Q&A

ガンフィーダGun Feeder, the small diameter and deep hole drilling machine with high speed rotation and high precision feed.
It achieves the longer tool life and the enhancement of productivity by the Sugino's special slide type drill whip guide system and coolant unit.
For further details, please click here. (To the lineup page)

In this page, you can review Q&A for Gunfeeder







Gun Feeder Q&A

Q1. What type of drill is a gun drill?

Unlike traditional processing methods, a gun drill does not step-feed difficult deep holes, but rather, carries out processing with a high degree of precision.



Q2. How is it different from a twist drill?

Twist drills need to perform deep hole processing via step feeding, and therefore, they require a large amount of processing tact time.
However, since gun drills can perform processing without step feeding, they are able to perform hole drilling with very high efficiency.


Q3. What type of shape does a gun drill have?

The gun drill consists of three main parts: an extra-hard blade, a shank, and a driver. The shank and extra-hard blade form a V-shaped cross section, with the shank being hollow.
Cutting oil flows through the inside of the drill and is injected from the oil holes on the edge of the cutting blade.
Since cutting-chips are discharged with the injected cutting oil to the back of the drill via the V-shape configuration of the cutter and shank, deep hole processing is able to be performed without the need of step feed processing.

 Figure: Shape of gun drill


Q4. Can it process any type of material?

In addition to S45C and SCM materials, the gun drill is able to process a wide range of materials including SUS and aluminum materials. Depending on processing conditions, the drill is also able to process difficult-to-cut materials such as titanium alloys.


Q5. How deep can a gun drill process?

In general, it can drill to a depth of about 50 to 100 times that of the hole diameter.


Q6. How curved is the hole?

Because the gun drill moves along the workpiece according to the guidance of pre-drilled holes, it can obtain superior straightness and off-center precision.
It depends on processing conditions, but

  • the degree of straightness can be kept below 0.01 mm for a length of 150 mm
  • the off-center precision can be kept below 0.2 mm for a length of 150 mm.

In addition, by using the Gun Feeder LR and rotating the workpiece in the opposite direction of the gun drill, it is possible to keep the off-center precision below 0.03 mm for lengths of 150 mm, which improves the off-center precision of the processing holes at each stage of the work.


Q7. How coarse is the surface of the hole?

The extra-hard blade of the gun drill has a guide pad.
The guide pad is pressed inside the hole, creating burnishing effects. This, in turn, provides for a superior coarseness of 3.2-0.2 µm Ra.


Q8. What are the cutting conditions of a gun drill?

Holes opened with the gun drill are drilled at a very high rotation speed, so the feed rate is relatively low.
The table below displays the general cutting speed and feed rate.

Cutting speed (m/min)

gunfeeder cuttingspeed

Feed rate (mm/rev)

gunfeeder feedrate


Q9. Is gun drill regrinding possible?

Yes, regrinding is possible.


Q10. What type of cutting oil should be used?

Please use a non-chlorine based cutting oil.
Suitable oils include Daphne Marg Plus GD-10 (Idemitsu Kosan).


Q11. What is the lifetime of a gun drill?

It depends on processing conditions, but the gun drill has an industry-proven track record of being regrinded and used at a processing rate of 150 to 200 pieces of SCM with a grade of 2.5 and depth of 100 mm.


Q12. Is it true that hardened materials can also be processed?

The gun drill has a history of processing holes for SCM (hardness of HRC40) at a grade of 5 and depth of 273 mm.
In addition, it can also process carburized and hardened materials at a grade of 3.5 and depth of 134 mm.
Please contact your nearest sales office for more information.