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String Trimmer & Brush Cutter Parts

What parts are included in this collection? Mow Town USA offers replacement string-trimmer and brush-cutter parts, including trimmer heads, replacement spools, bump knobs, head covers, cutting blades, blade adapters, washers, nuts, bolts, reducer bushings and related mounting hardware.

Shop by the original equipment part number, trimmer brand, model number, thread direction, arbor size, blade diameter and mounting style. Before ordering, compare the replacement part with the original component and verify every listed measurement.

How to Choose the Correct Trimmer or Brush-Cutter Part

1. Identify the exact component

  • Trimmer heads: complete cutting-head assemblies for compatible string trimmers and brush cutters.
  • Spools and bump knobs: replacement internal or external head components used to feed cutting line.
  • Head covers and bases: housings and retainers that protect and secure compatible spool assemblies.
  • Brush-cutter blades: metal or polymer cutting attachments designed for compatible equipment and approved applications.
  • Adapters, bushings and washers: mounting components that help match a blade or head to the equipment shaft and hardware.
  • Nuts and bolts: fasteners that secure compatible cutting attachments and head components.

2. Match the OEM or replacement part number

The original equipment part number is usually the most reliable starting point. Check the trimmer manual, illustrated parts diagram or number printed on the original head, spool, knob, blade or mounting component.

3. Confirm the shaft thread and direction

Trimmer heads and mounting nuts can use different thread sizes and may be right-hand or left-hand threaded. Match the thread diameter, pitch and direction before ordering. A part that appears similar might not attach correctly.

4. Check the arbor and mounting-hole size

Brush-cutter blades and adapters are commonly identified by blade diameter and center-hole or arbor size. Compare both measurements with the original equipment and confirm that the blade is approved for the trimmer or brush cutter.

5. Compare head type and line-feeding design

Replacement heads may use bump-feed, fixed-line, semi-automatic or fast-loading designs. Confirm that the mounting system, rotation direction, line capacity and operating design match the equipment.

6. Verify blade diameter and intended use

Use only a blade type and diameter approved by the equipment manufacturer. Brush, grass and polymer blades are designed for different cutting conditions and require compatible guards, handles and mounting hardware.

7. Inspect related mounting hardware

When replacing a head or blade, inspect the washer, nut, bolt, adapter, cover and retaining parts. Worn, cracked, bent or missing hardware can prevent secure installation.

Frequently Asked Questions

How do I know which trimmer head fits my equipment?

Match the original part number, shaft thread, thread direction, mounting style, rotation direction and any equipment applications shown in the product listing.

Are string-trimmer heads universal?

No. Some heads include adapters for several applications, but thread size, shaft style, rotation and guard requirements differ between machines.

What is the difference between a spool and a complete trimmer head?

A spool holds the cutting line inside a compatible head. A complete head normally includes the housing and feed mechanism, although included components vary by product.

How do I select a brush-cutter blade?

Confirm the blade diameter, center-hole or arbor size, blade style, rotation direction and equipment approval. Use the required guard and mounting hardware specified by the equipment manufacturer.

What does left-hand thread mean?

A left-hand threaded fastener tightens in the opposite direction from a standard right-hand thread. Match the original thread direction exactly.

Can I install a metal blade on any string trimmer?

No. The equipment must be designed and approved for that blade type. The correct guard, handle, harness, gearbox and mounting hardware may also be required.

Should I replace the mounting hardware with the cutting attachment?

Replace hardware that is worn, damaged, bent, cracked, stripped or missing. Confirm that every component matches the equipment and attachment specifications.

Where can I find replacement trimmer line?

Cutting line is available separately in our String Trimmer Line collection, organized by diameter, shape and package format.

How can I reduce the chance of ordering the wrong part?

Provide the equipment brand, model number, original part number, shaft or thread measurements and clear photos of the original component. Compare the specifications rather than relying only on appearance.

Find the Right Trimmer Replacement Part

Review each product listing for part number, thread size, arbor size, dimensions, mounting style and equipment application. For additional guidance, visit our Frequently Asked Questions page or contact Mow Town USA with your equipment information.

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Rotary # 17441 AERO-FLEX LINE BLADES .240"

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Aero-Flex Replacement Line Blades. Fits Rotary 17438, 17439, and 17440. Long lasting, easy to replace .240" width blades. Compatible with all Aero-...

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Rotary # 17440 AERO-FLEX SNAP & TRIM BLADE CONVERSION

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Aero-Flex Snap & Trim Line Blade Conversion. Easily converts Ryobi cordless auto-feed trimmers to a mini mower. Cuts through heavy vegetation w...

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Rotary # 17439 AERO-FLEX SNAP & TRIM CONVERSION

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Aero-Flex Snap & Trim Blade Conversion. Easily converts Craftsman/Black & Decker cordless auto-feed trimmers to a mini mower. Cuts through ...

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Rotary # 17438 AERO-FLEX TRIMMER HEAD

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Aero-Flex Universal Trimmer Head. Easy to change line blades take less then one minute to change. Aggressive cut gets the job done faster. Glider h...

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Rotary # 30113 KNOB LH MANUAL TWIST-FEED

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Dimensions: CASE QTY: 100 PALLET QTY: 40

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Rotary # 30112 KNOB RH MANUAL TWIST-FEED

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Dimensions: CASE QTY: 150 PALLET QTY: 60

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Rotary # 30055 ARBOR BOLT 10MMX1.25MM LHF HUSQVARNA

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Counter Sunk Arbor Bolt. Fits European made Straight Shaft Trimmers.Dimensions: SIZE: 10 X 1.25 (Left Hand) CASE QTY: 100 PALLET QTY: 100

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Rotary # 30054 ARBOR BOLT 10MMX1.0MM LHF SEMI

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Dimensions: SIZE: 10 x 1.0 CASE QTY: 150 PALLET QTY: 120

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Rotary # 30051 ARBOR BOLT 8MMX1.25MM LHF

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Arbor Bolt 8MM X 1.25MM LHFDimensions: SIZE: 8 x 1.25 CASE QTY: 200 PALLET QTY: 90

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Rotary # 50506 BRUSH CUTTER BLADE 300MM X 20MM UNIVERSAL

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Universal Formed Mulching Brush Cutter Blade. Used on machines that accept 20mm center hole.Dimensions: LENGTH: 300 mm C. H. DIA: 20 mm THICKNESS: ...

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Rotary # 50505 BRUSH CUTTER BLADE 300MM X 25.4MM UNIVERSAL

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Universal Formed Mulching Brush Cutter Blade. Used on machines that accept 25.4mm center hole.Dimensions: LENGTH: 300 mm C. H. DIA: 25.4000 mm THIC...

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Rotary # 50449 BLADE 14" X 20MM BRUSHCUTTER

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Brushcutter Blade 14" Length, 3-1/2" Width, .20mm C.H., 095" Thickness.Dimensions: LENGTH: 14" WIDTH: 3-1/2" C. H. DIA: 20 mm THICKNESS: 0.0950" CA...

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Rotary # 16705 DRIVE TUBE ATTACHMENT SLEEVE FOR STIHL

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Drive Tube Attachment Sleeve replaces Stihl 4140-791-7207. Old number 4140-791-7201. Used on Kombi units.Replaces: STIHL 4140-791-7207 STIHL 4140-7...

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Rotary # 13449 BRUSH BLADE 10" 3T X 1" BORE

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Windsor GRA3-255 Brush Blade 10" 3T x 1" Bore 2.25mm thick. Windsor grass and brush blades are made of Swedish steel and exceed all international s...

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Rotary # 12581 BRUSHCUTTER BLADE

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9" Razor Max Brushcutter Blade. Designed for fast and easy cutting of small trees, heavy brush, thick weeds and grass. Suitable for gas powered tri...

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Rotary # 12580 BRUSHCUTTER BLADE

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7" Razor Max Brushcutter Blade. Designed for fast and easy cutting of small trees, heavy brush, thick weeds and grass. Suitable for gas powered tri...

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Rotary # 8461 BRUSH BRUSH 9" X 1" 24T EIA

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EIA Series.Dimensions: DIAMETER: 9" C. H. DIA: 1" THICKNESS: 1.8000 mm NO. OF TEETH: 24 CASE QTY: 10 PALLET QTY: 120

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Rotary # 8459 BRUSH BLADE 8" X 1" 22T EIA

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EIA Series.Dimensions: DIAMETER: 8" C. H. DIA: 1" THICKNESS: 1.5000 mm NO. OF TEETH: 22 CASE QTY: 10 PALLET QTY: 80

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Rotary # 7857 BRUSH BLADE 9 "X 1" 24T MAXI

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Maxi Series/EIA Series.Dimensions: DIAMETER: 9" C. H. DIA: 1" THICKNESS: 1.8000 mm NO. OF TEETH: 24 CASE QTY: 10 PALLET QTY: 80

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Rotary # 4414 BRUSH BLADE 12"X3/4" 3T

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Includes Reducer Bushing to 20mm.Dimensions: DIAMETER: 12" C. H. DIA: 3/4" THICKNESS: 2.2500 mm NO. OF TEETH: 3 CASE QTY: 10 PALLET QTY: 144

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Rotary # 14843 THROTTLE CONTROL TRIGGER

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Throttle Control Trigger replaces Echo 17801052130. Fits SRM2100, 210, PE2000, 2400 & several other trimmer models.Replaces:ECHO 17801052130Di...

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Rotary # 7905 THROTTLE CONTROL BRUSH CUTTER

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Universal-Short Brush Cutter.Replaces:SHINDAIWA 72910-14320Dimensions: CASE QTY: 250 PALLET QTY: 24

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Original price $95.99 - Original price $95.99
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Rotary # 14823 UNIVERSAL TRIMMER GEAR BOX KIT

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Universal Trimmer Gear Box Kit for use with most brands and models of Brush Cutters & String Trimmers. Fits trimmers from 20cc to 40cc. Has 10m...

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Original price $95.99 - Original price $95.99
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Original price $80.99 - Original price $80.99
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Rotary # 14633 TRIMMER GEAR BOX FOR STIHL

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Trimmer Gearbox Head replaces Stihl 4137 640 0100. Complete unit with gears. Fits Stihl models: FR130, FR220, FR350, FR450, FR480, FS36, FS40, FS4...

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Original price $80.99 - Original price $80.99
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