DIN 338 - reduced shank

How to choose the right reduced shank drill bit

The reduced shank primarily solves chuck capacity limitations. When choosing, consider the following:

Required hole diameter

These drill bits are useful when you need a hole larger than a standard 13 mm chuck allows, but you do not want or cannot use a drill bit with a Morse taper shank.

Machine type

They are designed for hand drills, cordless drills, and bench drills equipped with a standard chuck.

If your machine has a Morse taper (MT) spindle, it is more suitable to use drill bits with Morse taper shank (e.g., DIN 345).

Power and stability

A larger diameter means higher torque. The drill must have sufficient power and allow low speed settings. With less powerful cordless tools, drilling larger diameters may be at the limit of their capacity.

Material being drilled

As with standard DIN 338 length, you can choose between HSS, ground versions, or cobalt versions depending on the hardness of the material.

Where and how reduced shank drill bits are used

They are mainly used for:

• installation of steel structures,
• drilling holes for larger bolts and threaded rods,
• modifying profiles and thicker steel sheets,
• service work in the field.

They are suitable where a Morse taper machine is not available but a larger hole is required.

Metal drilling must always be performed without hammer action.

How to work with reduced shank drill bits

When drilling larger diameters, it is necessary to:

• work at lower speeds,
• hold the drill firmly and steadily,
• secure the workpiece firmly,
• consider pre-drilling with a smaller bit for larger diameters.

A larger diameter means higher material resistance and greater load on both the tool and the drill bit. It is therefore important to work smoothly and avoid excessive feed pressure.