Garden / Brushcutters & Trimmers
User Manual for CRAFTSMAN 20V Max* String Trimmer/Edger CMCST900
Comprehensive user guide for the CRAFTSMAN 20V Max* String Trimmer/Edger (CMCST900). Includes assembly, operation, maintenance, and safety instructions.
Quick answers from the manual
Quick answer
- The CRAFTSMAN CMCST900 is a 20V cordless string trimmer and edger. It features adjustable height, an auxiliary handle, and a speed control switch. It uses .065" round nylon line. p. 1, 3
Key actions
- Install the guard p. 9
- Convert to edging mode p. 11
- Replace the spool p. 12, 13
First start
- Charge the battery fully before first use. p. 7, 8
Problems and fixes
Battery pack does not charge
Check receptacle, ensure battery is seated, or move to a location with 65-75°F air temperature.
p. 8Maintenance and reset
- Clear jams by removing the spool cap and clearing debris. p. 12
Technical specifications
| Parameter | Value | Meaning | Pages |
|---|---|---|---|
| Line Diameter | .065" (1.65 mm) | Recommended round nylon line size. | p. 12 |
Where to find it in the PDF
- Safety Instructions p. 4, 5, 6, 7
- Assembly p. 9, 10
- Operation p. 10, 11, 12
- Maintenance p. 12, 13, 14
Table of contents
Manual images
Click an image to enlargeQuick guide from the manual
The CRAFTSMAN CMCST900 is a 20V cordless string trimmer and edger designed for household trimming and edging applications. Before use, ensure the battery is fully charged. Always wear safety glasses and appropriate protective clothing. Keep bystanders at least 100 feet (30 m) away during operation.
Assembly and adjustments
Attaching the Guard: Slide the guard onto the trimmer head until it snaps into place. Secure it using the provided guard screw. Remove the covering from the line cut-off blade before use.
Attaching the Auxiliary Handle: Press the adjustment buttons on both sides of the upper housing. Position the handle and push it onto the housing until it snaps into place. Adjust the handle so your front arm is straight when in the working position.
Height Adjustment: Loosen the height-adjust collar by rotating it, move the upper housing to the desired height, and tighten the collar.
Operation
Battery Installation: Align the battery pack with the rails inside the tool handle and slide it in until firmly seated. Press the release button to remove.
Switching On/Off: Squeeze the lock-off button and then the On/Off trigger to start. Release the trigger to stop.
Speed Control: Use the speed control switch to toggle between 'LO' (extended runtime) and 'HI' (high-performance cutting).
Edging Mode: To convert to edging mode, remove the battery, pull down the turn-to-edge collar, rotate it 180 degrees counterclockwise until it snaps, and release.
Maintenance
Spool Replacement: Remove the battery. Press the release tabs on the spool cap to remove it. Clear debris, insert the new spool (Model CMZST065), and snap the cap back on.
Cleaning: Blow dirt and dust out of all air vents with clean, dry air at least once a week. Never use solvents or harsh chemicals.
Troubleshooting
If the unit does not start, check the battery charge and installation. If the line does not feed, clear debris from the spool housing and ensure the line is not tangled. If charging issues persist, contact an authorized service center.
Manufacturer information
CRAFTSMAN
Practical help
Common problems
Trimmer will not start
Check that the battery is fully seated and charged. Ensure the trigger is not locked.
Line not feeding automatically
Clear debris from the spool housing. Ensure the line is not tangled or welded to the spool.
Battery not charging
Ensure the battery is fully seated in the charger. Check for hot/cold pack delay.
Before use
- Charge the battery pack fully
- Wear ANSI Z87.1 approved safety glasses
- Ensure the guard is properly attached
- Inspect the area for wires or debris
- Check for damaged parts
Images and diagrams
- Fig A: Component identification including trigger, handle, and spool housing
- Fig B/C: Guard installation steps
- Fig D: Auxiliary handle adjustment
- Fig J: Converting the trimmer to edging mode
- Fig K: Spool cap removal and line clearing
Model compatibility
- Use only CRAFTSMAN chargers
- Use only .065" round nylon monofilament line
- Compatible with Versatrack™ wall storage system
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.