Thunderbolt 57991 OwnerS Manual

The Thunderbolt 57991 is a high-performance power tool designed for professional and heavy-duty applications. It features a robust motor, variable speed control, ergonomic design, safety lock-off switch, quick-change chuck system, and compatibility with a wide range of accessories. Powered by a 18V lithium-ion battery (included) or AC adapter (sold separately). Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Safety Instructions 3. Assembly & Initial Setup 4. Specifications 5. Controls and Indicators 6. Basic Operation 7. Advanced Functions 8. Maintenance & Care 9. Storage 10. Warranty Information 11. Troubleshooting

Features at a Glance

Key components: High-torque brushless motor, Variable speed trigger, LED worklight, Battery charge indicator, Quick-release chuck, Depth adjustment gauge, Safety clutch.

Feature	Description
Brushless Motor	Provides increased power, longer runtime, and extended tool life
Variable Speed Trigger	Allows precise speed control from 0 to 3,200 RPM
LED Worklight	Illuminates dark work areas; activates with trigger press
Battery Charge Indicator	3-LED display shows remaining battery capacity
Quick-Release Chuck	Allows fast, keyless bit changes (accepts 1/4" and 1/2" bits)
Depth Adjustment Gauge	Ensures consistent drilling/driving depth
Safety Clutch	Prevents over-torque and bit slippage
Ergonomic Soft Grip	Reduces user fatigue during extended use
Lock-off Button	Prevents accidental start-up
Belt Clip	Allows for convenient carrying and access

Safety Instructions

Read all instructions before use. Failure to follow warnings may result in electric shock, fire, or serious injury.

Work Area Safety: Keep work area clean, well-lit, and free of clutter.
Electrical Safety: Do not expose tool to rain or wet conditions. Do not abuse the cord.
Personal Safety: Use safety equipment (goggles, dust mask, hearing protection).
Tool Use & Care: Use the correct tool for your application. Do not force the tool.
Battery Tool Use: Use only manufacturer-specified charger and batteries.
Service: Have tool serviced by qualified personnel using identical replacement parts.

WARNING! Keep hands away from rotating parts. Always disconnect battery before making adjustments.

Assembly & Initial Setup

Unpack and inspect all contents. Ensure all parts are present and undamaged.

Charging the Battery: Insert battery into charger. Charge until indicator shows full (approx. 60 min).
Installing the Battery: Slide battery pack into tool base until it clicks securely.
Installing a Bit: Pull chuck sleeve forward, insert bit, release sleeve to lock.
Adjusting Depth Gauge: Loosen collar, set desired depth, tighten collar.
Attaching Belt Clip: Insert clip into slot on tool body and secure with provided screw.

CAUTION! Do not use damaged batteries or chargers. Ensure tool is off before assembly.

Specifications

Model: Thunderbolt 57991
Motor Type: Brushless, High-Efficiency
No-Load Speed: 0-3,200 RPM
Max Torque: 650 in-lbs
Chuck Capacity: 1/4" & 1/2" hex quick-release
Battery: 18V Lithium-Ion, 4.0Ah (included)
Charger: 18V Fast Charger (input: 120V AC, 60Hz)
Weight (tool only): 3.5 lbs
Sound Pressure: 85 dB(A)
Vibration: <2.5 m/s²
Warranty: 3-Year Limited Tool, 1-Year Battery

Controls and Indicators

Tool Body: Variable Speed Trigger, Forward/Reverse Switch, Mode Selector (Drill/Driver/Hammer), LED Worklight Button, Battery Release Latch.

Battery Pack: 3-LED Charge Indicator (press button to check), Release Buttons.

Operation Modes: Select via dial: Drill icon (standard drilling), Driver icon (screwdriving), Hammer icon (hammer drilling for masonry).

Forward/Reverse: Slide switch left for forward (clockwise), center for lock, right for reverse (counter-clockwise).

Basic Operation

Drilling: Select Drill mode, install drill bit, apply steady pressure. Screwdriving: Select Driver mode, install driver bit, set clutch torque ring.

Ensure tool is off and battery is installed.
Select operating mode (Drill/Driver/Hammer) via dial.
Set forward/reverse direction.
Place bit on workpiece.
Squeeze trigger to start. Speed increases with trigger pressure.
Release trigger to stop.
Use LED button to toggle worklight independently.

Tip: For precision, start at low speed. Let the tool do the work; avoid excessive force.

Advanced Functions

Hammer Drilling: For masonry/concrete. Select Hammer mode, use carbide masonry bit.

Torque Clutch Settings: Rotate clutch ring (1-20 + Drill) to match fastener size/material.
Depth Stops: Use depth gauge for repeated hole depths.
Battery Fuel Gauge: Press button on battery to see remaining charge (Green=High, Yellow=Medium, Red=Low).
Kickback Control: Electronic system detects bind-up and stops tool to reduce reaction.
Accessory Compatibility: Accepts standard hex-shank drill bits, driver bits, hole saws, mixing paddles.

WARNING! Wear safety goggles when hammer drilling. Secure workpiece. Do not use hammer mode on metal or wood.

Maintenance & Care

Regular maintenance ensures optimal performance and longevity.

Cleaning: Disconnect battery. Wipe exterior with dry, soft cloth. Use brush to clear vents.
Chuck Maintenance: Occasionally clean chuck jaws. Apply light machine oil if stiff.
Battery Care: Store at room temperature. Do not fully discharge regularly.
Motor Brushes: Not user-serviceable (brushless motor).
Inspection: Regularly check for damage to housing, cord (if applicable), and bits.

CAUTION! Do not use solvents or immerse tool in liquid. Do not lubricate internal parts.

Storage

Store tool in a dry, secure place out of reach of children.

Remove battery before long-term storage.
Store battery at 40-50% charge if not used for over 30 days.
Use provided case or hang tool via belt clip.
Keep away from extreme heat or cold.

CAUTION! Do not store with bit installed under pressure.

Warranty Information

Thunderbolt warrants this tool to be free from defects in material and workmanship for a period of THREE (3) YEARS from date of purchase for the tool, and ONE (1) YEAR for the battery and charger, under normal use and maintenance. This warranty does not cover damage from abuse, alteration, neglect, commercial use, or normal wear. Proof of purchase is required. For warranty service, contact authorized service center or call 1-800-555-TOOL or visit www.thunderbolttools.com/support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Tool does not start	Dead battery, lock-off engaged	Charge battery; ensure lock-off button is released.
Reduced power/speed	Weak battery, clogged air vents	Charge battery; clean vents; check for overload.
Bit slips or doesn't hold	Worn/dirty chuck, wrong bit type	Clean chuck jaws; ensure bit is fully inserted and correct size.
Excessive vibration/noise	Damaged bit, loose accessory	Replace bit; tighten accessory; check for bearing wear.
Battery not charging	Faulty charger, temperature extreme	Check connections; move to 50°F-104°F environment; try different outlet.
LED worklight not working	LED failure, connection issue	Tool function unaffected; contact service for LED replacement.

Reset: Remove battery for 60 seconds to reset electronics.

Service: 1-800-555-TOOL; www.thunderbolttools.com/support