Taper Shank Drill Bits: Understanding Morse Taper Sizes MT1 to MT6
Taper shank drill bits are widely used in industrial drilling machines for machining metal and other materials. Unlike straight shank drill bits, they feature a tapered shank that fits directly into a matching machine spindle or taper sleeve.
One important feature of taper shank drills is the Morse taper (MT) system. Different taper sizes, such as MT1, MT2, MT3, MT4, MT5, and MT6, are designed for different machine spindle connections and tool sizes.
Understanding the Morse taper system helps buyers select suitable drill bits, check machine compatibility, and understand product specifications.
What Is a Taper Shank Drill Bit?
A taper shank drill bit is a twist drill designed with a conical shank instead of a straight cylindrical shank. It is commonly used on bench drill presses, pillar drills, radial drilling machines, lathes, and other industrial machine tools.
A typical taper shank drill bit consists of three main sections:
▪Cutting Point: The tip of the drill bit that starts the hole and penetrates the workpiece.
▪Fluted Body: The spiral-fluted section responsible for cutting and removing chips during drilling.
▪Taper Shank: The conical section that fits into the machine spindle or a matching taper sleeve. It usually includes a tang at the end.
The tapered connection provides a self-holding fit through friction between matching surfaces, which is the primary means of transmitting torque. The tang at the end of the shank is mainly used for ejection. A drift key presses against the tang to release the taper's self-holding grip when removing the drill.
Compared with straight shank drills, taper shank drills are commonly used for larger drilling diameters and heavier machining applications. When properly seated and kept clean, the tapered connection provides stable tool holding and reliable torque transmission.
Understanding Morse Taper Sizes: MT1 to MT6
Morse taper is a standardized system used to connect cutting tools to machine spindles. Each taper size has specific dimensions, including its large-end diameter, small-end diameter, and taper length.
The Morse taper system includes multiple sizes. For DIN 345 taper shank drills, MT1 to MT6 are commonly used.
As the Morse taper number increases, the shank generally becomes larger. Each size is designed for different tool dimensions and machine spindle capacities.
Common Drill Diameter Ranges by Morse Taper Size
For standard DIN 345 twist drills with normal taper shanks, different drill diameter ranges correspond to different Morse taper sizes. The following table provides a general reference:
| Morse Taper | Normal Taper Shank Drill Diameter Range (mm) |
|---|---|
| MT1 | 3.00–14.00 |
| MT2 | 14.25–23.00 |
| MT3 | 23.25–31.50 |
| MT4 | 32.00–50.50 |
| MT5 | 51.00–76.00 |
| MT6 | 77.00–100.00 |
For example, a 10 mm DIN 345 taper shank drill typically uses an MT1 shank, while a 20 mm drill typically uses an MT2 shank. A 30 mm drill commonly uses MT3, a 40 mm drill MT4, a 60 mm drill MT5, and an 80 mm drill MT6.
Note: These ranges are general engineering references for normal taper shank drills. Exact diameter assignments and available sizes should be checked against the relevant product standard and manufacturer's specifications.
The Morse taper number identifies the shank connection, not the cutting diameter itself.
Applications of Different Taper Shank Drill Sizes
Different Morse taper sizes are designed for different drill diameters and machine capacities.
Smaller sizes, such as MT1 and MT2, are commonly found on smaller drilling machines and are suitable for relatively small diameter drills. MT3 and MT4 are widely used for larger drills on industrial drilling machines and lathes. MT5 and MT6 are generally used for large-diameter drills and machines with greater spindle capacity.
The actual application depends on the drill diameter, workpiece material, machine design, and cutting conditions. A larger Morse taper does not automatically mean better drilling performance; the complete tool and machine specifications must be considered.
What to Consider When Choosing Taper Shank Drill Bits
When purchasing taper shank drill bits, Morse taper size is only one part of the product specification. Buyers should also consider the following factors.
Drill Diameter: Choose the diameter according to the required hole size. Confirm the corresponding Morse taper size using the reference above, then check it against your machine spindle.
Drill Length: Overall length and flute length affect drilling depth and working clearance. Longer drills can reach deeper holes, while shorter designs generally provide greater rigidity.
Material and Coating: High-speed steel (HSS) is commonly used for general-purpose metal drilling. Different grades, such as M2 and M35, offer different performance characteristics. Coatings such as TiN can improve wear resistance and tool life under suitable cutting conditions.
Workpiece Material: The drill bit should be selected according to the material being machined, such as carbon steel, alloy steel, stainless steel, or cast iron. Cutting speed, feed rate, and cooling conditions should also be adjusted accordingly.
Machine Compatibility: The Morse taper shank must match the machine spindle or a suitable reducing sleeve. For example, an MT2 drill can be fitted into an MT3 spindle using an MT3-to-MT2 reducing sleeve.A reducing sleeve allows a smaller taper shank to fit into a larger spindle socket. It cannot be used to fit a larger shank into a smaller socket.If the spindle taper is unknown, measure the large-end diameter of the spindle socket and compare it with a Morse taper dimension chart, or check the machine manual.
Proper Installation: Keep the taper shank and spindle socket clean and dry before installation. Oil, coolant, chips, or damaged contact surfaces can affect the fit and cause slipping. Insert and seat the drill according to the machine manufacturer's instructions. Use a suitable drift key for removal when necessary.
Conclusion
Taper shank drill bits are designed for reliable tool holding and efficient drilling in industrial machining applications. The Morse taper system provides standardized shank connections, while DIN 345 defines specifications for taper shank twist drills.
Understanding the differences between MT1, MT2, MT3, MT4, MT5, and MT6 makes it easier to identify the correct taper shank drill bit for different drilling requirements.
When selecting a drill, consider the diameter, length, material, Morse taper size, and machine compatibility to ensure the right tool for the job.
Not sure which Morse taper your machine uses? Contact us with your spindle specification and required drill diameter, and we will help you confirm the appropriate taper shank drill. You can also browse our taper shank drill range by Morse taper size.
Post time: Nov-13-2026
