Tools / Drills
Bosch GBH 18V-21 Professional Cordless Hammer Drill User Manual
Quick guide for the Bosch GBH 18V-21 Professional cordless hammer drill. Includes instructions for battery installation, tool changing, operating modes, and safety precautions.
Table of contents
Quick guide from the manual
This document provides essential information for the safe and efficient operation of the Bosch GBH 18V-21 Professional cordless hammer drill. Always ensure the battery is removed before performing any maintenance or changing tools to prevent accidental startup.
Device Description
The GBH 18V-21 is a cordless rotary hammer designed for hammer drilling in concrete, brick, and stone, as well as light chiseling. It is also suitable for drilling without impact in wood, metal, ceramic, and plastic, and for screwdriving.
Operation
The operating mode is selected using the impact/mode selector switch (7). To change the mode, press the release button (6) and turn the switch until it clicks into the desired position. Available modes include hammer drilling, drilling without impact, and chiseling. The rotational direction switch (8) allows for clockwise or counter-clockwise rotation. Always set to clockwise for hammer drilling, drilling, and chiseling.
Battery Handling
Use only the chargers listed in the technical data. The battery features a charge indicator; press the button on the battery to check the charge level. Protect the battery from moisture, water, and extreme temperatures.
Maintenance and Cleaning
Keep the power tool and ventilation slots clean for safe operation. Replace a damaged dust protection cap (3) immediately; it is recommended to have this done by an after-sales service center. Clean the tool holder (2) after each use.
Safety Precautions
- Always wear hearing protection.
- Use auxiliary handles if supplied with the tool.
- Hold the tool by insulated gripping surfaces when performing operations where the cutting accessory may contact hidden wiring.
- Start drilling at low speed with the bit in contact with the workpiece.
Manufacturer information
Bosch
Practical help
Common problems
Tool does not start
Check battery charge level and ensure the battery is properly inserted.
Drill bit jams
Switch off the tool immediately and release the bit. Switching on with a blocked tool causes high reaction torques.
Reduced battery runtime
The battery is likely worn out and needs to be replaced.
Before use
- Ensure the battery is fully charged.
- Check that the auxiliary handle is securely tightened.
- Verify the correct operating mode is selected.
- Ensure the dust protection cap is not damaged.
- Check that the drill bit or chisel is properly inserted and locked.
Specs in practice
- Rated voltage
- 18V DC, indicating the battery system required.
- Max. drilling diameter (Concrete)
- 21 mm, the maximum capacity for hammer drilling in concrete.
Images and diagrams
- Figure A: Adjusting the auxiliary handle.
- Figure B1: Inserting SDS-plus tools.
- Figure B2: Removing SDS-plus tools.
- Figure C: Setting the rotational direction.
- Figure D: Setting the drilling depth.
Model compatibility
- Compatible with Bosch GBA 18V and ProCORE18V battery series.
- Compatible with Bosch GAL 18, GAX 18, and GAL 36 series chargers.
Manual page author
Emily Carter
User documentation editor
Prepares concise manual descriptions and highlights the most useful setup, operation, and maintenance information for readers.