200LH 15 PC Set

DRILLCO 200LH 15-Piece Left Hand Drill Bit Set — Counterclockwise Drilling for Broken Bolt Removal

The DRILLCO 200LH 15-piece left hand drill bit set is a general-purpose High Speed Steel (HSS) drill set designed for counterclockwise drilling applications. It is engineered for use in close-center multiple spindle gear-driven drilling heads where adjacent spindles operate alternately left and right hand, as well as in left hand screw machines. The set is also a practical solution for drilling out broken bolts, where the counterclockwise cutting action can back out a fastener as the drill engages it. Manufactured in the United States, the set covers 1/16" through 1/2" in 32nds increments across 15 pieces.

Technical Specifications

Available Sizes

Unlike standard right-hand drill sets, the 200LH features left-handed flutes and cutting edges that rotate counterclockwise, allowing the drill to simultaneously cut and back out broken fasteners during the drilling operation. The bright finish and 118° conventional point make this set particularly well suited for non-ferrous materials such as aluminum, where a coating-free surface promotes chip flow and reduces built-up edge. Jobber length provides the reach needed for most field and shop applications without sacrificing rigidity.

Key Features & Benefits

Left-Handed Flutes and Cutting Edges

The counterclockwise flute geometry is the defining characteristic of this set, enabling the drill to engage and often back out broken bolts or studs as it cuts. This can eliminate the need for additional extraction tooling and reduce job time significantly on fastener removal tasks.

General Purpose HSS Construction

Made from general purpose High Speed Steel, these drills are suitable for a broad range of materials including low to medium strength steels, aluminum, and other non-ferrous metals. HSS is the most widely used tool material for general purpose drilling, offering a reliable balance of toughness and wear resistance.

118° Conventional Point

The 118° conventional point is optimized for rapid penetration into mild steels and free-machining materials. This geometry is a proven standard for general metalworking applications and is compatible with most drill press and hand-drill setups.

Bright Finish

The bright finish — a smooth, polished surface treatment with no coating — promotes increased chip flow and is ideal for drilling in non-ferrous materials like aluminum. It avoids the adhesion issues that coated bits can sometimes present in softer metals.

Jobber Length

Jobber length is the most common drill length because it provides extra reach while remaining usable in the vast majority of applications. This makes the 200LH set versatile across both machine and hand-held drilling setups.

15-Piece Range (1/16"–1/2" by 32nds)

The set covers a comprehensive range of fractional sizes in 32nds increments from 1/16" to 1/2", giving contractors and machinists the correct size for virtually any broken bolt or left-hand drilling task without needing to source individual bits.

Common Applications

Broken Bolt and Stud Removal

The primary application for left-hand drills is drilling into broken bolts or studs; the counterclockwise cutting action frequently backs the fastener out of the hole as the drill engages it, recovering the threaded hole without damage.

Close-Center Multiple Spindle Gear-Driven Drilling Heads

These drills are specifically designed for use in close-center multiple spindle gear-driven drilling heads where adjacent spindles operate alternately left and right hand, requiring a dedicated left-hand cutting tool.

Left Hand Screw Machines

The 200LH series is engineered for use in left hand screw machines, where the spindle rotation direction requires a left-hand cutting geometry to produce accurate holes.

Non-Ferrous Material Drilling

The bright finish makes these drills well suited for drilling aluminum and other non-ferrous materials, where smooth chip evacuation is critical to hole quality and tool life.

Product Documents

• Safety Data Sheet (SDS)
• Drillco Product Linecard

Safety Data Summary

Hazard Information

• During normal operation, HSS drill bits do not present inhalation, ingestion, or other chemical hazards.
• Grinding, cutting, machining, burning, or welding these products may release dusts, fumes, or vapors that present health hazards if exposure limits are exceeded.
• Excessive inhalation of metallic fumes and dusts may cause irritation of eyes, nose, and throat; symptoms may include metallic taste, dryness and irritation of the throat, chills, and fever persisting 12–48 hours.
• Chromium (present 0–5% by weight) is listed as a carcinogen by NTP and OSHA; various forms of dermatitis, inflammation and/or ulceration of the upper respiratory tract, and possibly cancer of nasal passages and lungs are associated with chromium exposure.
• Tungsten (5–10% by weight): some evidence of pulmonary involvement such as cough.
• Vanadium (0–5% by weight): eye and respiratory tract irritant.
• Cobalt dust (if present from grinding) is reported as the most probable cause of respiratory diseases including occupational asthma and interstitial fibrosis.
• Skin contact with dust can cause irritation or allergic skin rash due to cobalt sensitization.
• Fine metal particles produced when ground or sawed can burn; high concentrations in air may present an explosion hazard.
• NFPA Hazard Rating: Health 1; Flammability 0; Reactivity 0.

Personal Protective Equipment

• Wear safety glasses or goggles with side shields; do not wear contact lenses when handling these materials.
• Cloth or leather gloves are recommended when contact with dust or mist is likely.
• Use an appropriate NIOSH-approved respirator if airborne dust concentration exceeds the applicable PEL or TLV.
• Hearing protection may be required.
• Always use machine guards and wear protective clothing to prevent injury in the event of tool breakage.
• Employer should provide an eye wash station within the immediate work area for emergency use.

Safe Handling

• Use only with local exhaust ventilation adequate to limit personal exposure to airborne dust below PEL or TLV levels.
• Clean up using methods that avoid dust generation: vacuum with appropriate filters, wet dust mop, or wet clean-up.
• Wash hands thoroughly after handling and before eating or smoking; wash exposed skin at end of work shift.
• Do not shake clothing, rags, or other items to remove dust — remove dust by washing or vacuuming with appropriate filters.
• Store in a dry place in a manner that prevents accidental environmental contamination from traces of industrial lubricants or wetting oils.
• Soiled clothing should be laundered separately.
• Incompatible materials: strong acids, strong oxidizers.
• Emergency phone number: CHEM-TEL INC 1-800-255-3924; General Information: 800-851-3821.

Frequently Asked Questions

Q: What is the primary purpose of a left-hand drill bit set like the 200LH?
A: Left-hand drills are used for counterclockwise drilling, most commonly to remove broken bolts. The counterclockwise cutting action can back out a broken fastener as the drill engages it. They are also used in close-center multiple spindle gear-driven drilling heads where adjacent spindles operate alternately left and right hand, and in left hand screw machines.

Q: What sizes are included in the 200LH15 set?
A: The set contains 15 pieces covering 1/16" through 1/2" in 32nds increments.

Q: What material are the drill bits made from?
A: The bits are made from general purpose High Speed Steel (HSS), which is suitable for most materials including low to medium strength steels, aluminum, and other non-ferrous materials.

Q: What type of finish do these drills have, and what materials is it best for?
A: The 200LH drills have a bright finish — a smooth, polished surface with no coating. This finish is ideal for drilling in non-ferrous materials like aluminum, as it promotes increased chip flow.

Q: What point angle do these drills use?
A: These drills feature a 118° conventional point, which is designed for rapid penetration and is used for mild steels and free-machining materials.

Q: Are there any critical operating tips for getting the best performance from these drills?
A: Yes — speed, feed, and lubrication are all critical to cutting tool performance with these bits. Proper attention to all three factors will help maximize tool life and cutting efficiency.