How to Choose the Right Drill

Choosing the right drill is critical for achieving accuracy, efficiency, and tool longevity in any machining or fabrication task. At Travers Tool Co., we understand that one size does not fit all when it comes to drilling.

From industrial-grade performance to affordable options for hobbyists, we offer drills for every skill level, material, and budget—plus everything in between. This drill buying guide will help you understand the different types of drills available and how to choose a drill for your specific application.

If you’re new to drilling, you may also find our guide on How To Drill A Hole helpful before diving into drill selection.

1. Jobber Drills

overview:

Jobber drills are the most commonly used type of twist drill. Known for their versatility, they feature a moderate flute length and are ideal for general-purpose drilling.

Best For:

A wide range of materials, including steel, aluminum, plastic, and wood
General shop use
Applications requiring moderate hole depths

Travers Offers:

High-Speed Steel (HSS) Jobber Drills: Cost-effective, suitable for most ferrous and non-ferrous metals
Cobalt Jobber Drills: Excellent for harder materials like stainless steel and titanium
Carbide Jobber Drills: Superior wear resistance, ideal for high-production environments

2. Stub Drills (Screw Machine Length)

Overview:

Stub drills are shorter than jobber drills, providing greater rigidity and reduced tool deflection. This makes them excellent for precision work.

Best For:

Shallow hole drilling or starting a deeper hole (often used instead of spotting & center drills)
Hard materials and tighter tolerance jobs
CNC machining where rigidity is essential

Travers Offers:

HSS, cobalt, and solid carbide options
Coated versions including TiN, TiAlN, and others for enhanced performance and tool life

3. EXTRA-LONG Drills

Overview:

Extra-long drills, aircraft extension drills and taper length drills are designed for drilling deep or hard-to-reach holes. Aircraft extension drills feature an extended shank with a relatively short flute length, which provides added rigidity and minimizes deflection during deep-hole drilling. Some extra-long drills have extended flute length and a shorter shank.

Best For:

Aerospace and automotive applications
Deep hole drilling where access is limited
Reaching beyond obstructions or into cavities

Travers Offers:

Standard and premium brands
HSS and cobalt versions
Multiple length options, including standard and extra-long

4. Parabolic Drills

Overview:

These drills feature a unique flute geometry that enhances chip evacuation, especially in deep hole drilling.

Best For:

Soft materials like aluminum and plastic
Deep hole drilling with improved chip clearance
Reducing the risk of jamming

Travers Offers:

HSS, cobalt and solid carbide options
Coated options available for specific material or operation compatibility
Parabolic Jobber Drills
Parabolic Screw Machine Length Stub Drills
Parabolic 3 Flute CNC Drills
Parabolic Taper Length Drills
Parabolic Extra Long Drills

5. Spotting & Center Drills

Spotting Drills And Center Drills (Combination Drill & Countersink)

Overview:

When preparing to drill precise holes, both spotting drills and center drills are used to create a starting point that prevents the main drill from walking or drifting. While they may seem similar, they serve different purposes and have distinct designs.

Design Features:

Shorter overall length and very rigid

Best for:

CNC or manual operations
High-precision hole positioning
Creating a precise starting point for a twist drill to prevent walking and ensure hole accuracy

Travers Offers:

Single and double-ended designs
Available in HSS, cobalt, and carbide

(a) Spotting Drills

Overview:

Create an accurate starting point for a twist drill, in CNC and manual precision drilling applications.

Design Features:

Tip angles (including 90°, 120°, 140° and others) are chosen to match or exceed the tip angle of the subsequent drill

Best for:

High-accuracy hole location
CNC or manual operations where precision is critical

(b) Center Drills (Combination Drill & Countersink)

Overview:

Create a center hole with a chamfer (usually 60°) for turning between centers.

Design Features:

Two-part point design: a small pilot drill followed by a countersink
Creates a conical seat (often 60°) used for lathe centers or to guide longer drills

Best for:

Lathe work (turning between centers)
Creating shallow holes with a chamfer
Guiding drills in light-duty manual drilling operations

Key Differences at a Glance:

Feature	Spotting Drill	Center Drill
Main Purpose	Accurate drill positioning	Creating center holes/chamfers
Tip Angle	90°, 120°, 140°, etc.	Typically 60°, but 82°, 90°, 118°, and 120° are also available
Includes Countersink?	No	Yes
Ideal Use	CNC & manual precision drilling	Lathe work, drill guidance
Design	Single-point angle	Dual-stage (drill + countersink)

Travers Offers:

Spotting Drills: Available in HSS, cobalt, and carbide; various tip angles for material compatibility
Center Drills: Single- and double-ended; HSS, cobalt and carbide; ideal for lathe and manual work setups

6. SOLID Carbide Drills

Overview:

Solid carbide drills are designed for high-speed applications and long tool life, even in the most demanding conditions.

Best For:

High-volume production
Hard and abrasive materials
Soft materials like plastic
CNC and automated machining

Travers Offers:

Uncoated and coated (including TiAlN, AlTiN, etc.) options
Coolant-through designs for improved chip evacuation

7. Indexable Insert Drills

Overview:

Indexable Insert Drills feature replaceable inserts instead of a solid cutting edge, offering significant cost savings over time.

Best For:

Large-diameter holes
High-speed CNC operations
Production environments seeking efficiency and lower long-term tooling costs

Travers Offers:

Leading brands including Allied, Iscar, Korloy, Kyocera, Terra Carbide, and Ultra-Dex
Inserts for various materials and machining conditions

8. Reduced Shank Drills (Silver & Deming)

Overview:

Reduced shank drills are designed to drill large holes without requiring equally large drill chucks. By incorporating a reduced diameter shank (often 1/2") these tools allow operators to use large-diameter drills in standard 1/2" chucks.

Silver & Deming drills are the most common type of reduced shank drill, typically ranging in size from 33/64" to 1-1/2" in diameter with a 1/2" shank, and up to 2” with a 3/4” shank

Best For:

Drilling large-diameter holes in metal, wood, and plastics
General-purpose use in drill presses, milling machines, lathes, and handheld power drills
Applications where large size drill chucks aren't available or practical

Features:

Reduced shank fits standard chucks
Typically 3" flute length and 6" overall length
Commonly made of High-Speed Steel (HSS), or cobalt
Some models include 3-flat shanks to prevent slippage in the chuck

Travers TIP:

Use slower speeds and ample cutting fluid when drilling large holes with Silver & Deming drills—especially in harder materials like stainless steel—to extend tool life and improve hole quality.

9. Specialty Drills

Travers Tool also offers a wide range of specialty drills to meet unique manufacturing needs:

Left-Hand Drills: Useful for removing broken screws or bolts
Step Drills: Ideal for drilling multiple diameters in thin material without replacing the tool
Masonry Drills: Designed for brick, concrete, and stone
Taper Shank Drills: Have a Morse Taper that mounts directly to the machine’s spindle

Spade Drills: For drilling shallow holes in difficult materials
Micro Twist Drills: For machining very small holes with extreme precision

10. Understanding Drill Point Angles

The point angle of a drill refers to the angle formed at the tip of the drill bit. It determines how the drill enters the material and how it removes chips. Selecting the correct point angle is essential for maximizing tool life, minimizing wear, reducing downtime, and achieving clean, accurate holes.

Here are the most common drill point angles and when to use them:

118° Point Angle (General-Purpose Standard)

Best For:

Mild steel, soft metals, wood, and plastics
General-purpose drilling in job shops or maintenance

Features:

Standard angle found on most HSS jobber drills
Good balance between cutting speed and durability
Requires spotting or center drilling in precision applications, especially on harder materials

135° Point Angle (Split Point or Self-Centering)

Best For:

Harder materials like stainless steel, alloy steels, and cast iron
CNC and manual medium-to-high production applications

Features:

Flatter angle that cuts with less pressure and resists walking
Usually features a split point for self-centering without spotting
Improved heat resistance and longer tool life in tough materials

>140° Point Angle (High-Performance Applications)

Best For:

Very hard materials (e.g., titanium, Inconel, hardened steels)
Deep-hole drilling or high-precision work

Features:

Greater resistance to chipping or edge wear
Often found on carbide drills with advanced coatings
Requires adequate machine rigidity and coolant

Choosing the Right Point Angle:

Material	Recommended Point Angle
Soft (wood, plastic, aluminum)	90°–118°
Mild steel, brass, bronze, aluminum	118°
Hardened steel, stainless, cast iron	135°
Titanium, Inconel, high-temp alloys	135°–140° (or larger)
Spotting applications	Equal to or greater than the main drill

Travers TIP:

If you're drilling multiple types of materials, 135° split point drills offer a good balance of performance and versatility. For very precise work, especially in CNC setups, the spotting drill point angle should be the same or slightly larger than the main drill to ensure clean entry for a precise location.