Strimmer Parts

What are strimmer parts?

Strimmer parts are the replacement components used to keep grass trimmers, strimmers, and brushcutters cutting and running properly. A strimmer uses a fast-spinning head fitted with nylon line or small blades to cut grass, weeds, and edges in places a mower cannot reach. Because the line wears down as it cuts, and many parts are exposed to dirt, vibration, and impacts, strimmers need regular replacement parts to stay in good working order.

Strimmer parts range from everyday consumables, such as trimmer line and spools, to head parts like bump knobs and spool covers, and engine parts for petrol models. Replacing worn parts quickly and correctly keeps a strimmer cutting cleanly and is usually much cheaper than buying a new machine.

Common strimmer parts include:

• Trimmer line - the nylon cord that spins at high speed to cut grass and weeds
• Spools - hold the trimmer line inside the cutting head
• Spool covers - cover and hold the spool in place inside the head
• Bump knobs - also called tap knobs, these are tapped on the ground to release more line on bump feed heads
• Trimmer heads - complete cutting heads that replace worn or broken originals
• Plastic blades - swing tip blades used on some cordless and electric trimmers instead of line
• Brushcutter blades - metal blades for cutting thick grass, brambles, and undergrowth
• Engine parts - spark plugs, air filters, fuel filters, primer bulbs, starter parts, and carburettor parts for petrol strimmers
• Guards and harnesses - protect the user and help carry the weight of larger machines

Key features:

• Restores cutting performance - fresh line and good head parts keep the strimmer cutting cleanly
• Quick and easy to fit - many parts can be replaced in minutes with no special tools
• Wide range of sizes - trimmer line and parts available to suit many machines
• Replacement designs - made to fit many popular brands and models
• Cost-effective - replacing parts is much cheaper than replacing the strimmer
• Supplied in packs - many consumables come in multi-packs for convenience

In simple terms, strimmer parts are the components that keep a strimmer’s line feeding, head turning, and engine running.

Why are strimmer parts essential?

Strimmer parts are essential because strimmers work hard in tough conditions. Trimmer line wears down every time it touches the ground, walls, fences, and stones. Spools, covers, and bump knobs take constant knocks, and engine parts are exposed to dust, grass, and vibration. If these parts wear out or break, the strimmer can stop feeding line, cut poorly, vibrate, or fail to start.

Their main benefits are:

• Clean, efficient cutting - the right line and blades give a neat finish with less effort
• Reliable line feed - good spools, springs, and bump knobs keep line feeding smoothly
• Less downtime - keeping spare line and parts on hand means work can carry on without delay
• Reduced vibration - correctly fitted and balanced parts help the strimmer run smoothly
• Safer use - secure heads, covers, and guards reduce the risk of parts coming loose
• Easier starting - fresh spark plugs, filters, and starter parts help petrol strimmers start reliably
• Longer machine life - replacing worn parts early prevents damage to the motor, engine, and drive
• Lower running costs - repairs are usually much cheaper than replacing the whole machine

These parts are important for a wide range of machines and users, including:

• Electric strimmers - line, spools, spool covers, and guards
• Cordless strimmers - line, spools, and plastic swing tip blades
• Petrol strimmers - line, trimmer heads, bump knobs, and engine parts
• Brushcutters - metal blades, heavy-duty line, heads, and harnesses
• Homeowners and DIY users - keeping garden strimmers ready for use
• Professional gardeners and landscapers - keeping strimmers and brushcutters working all season
• Grounds maintenance teams - parks, verges, sports grounds, and estates
• Farmers and estate workers - clearing fence lines, ditches, and rough ground

The main types of strimmer parts

Strimmer parts are usually grouped by the part of the machine they belong to.

Trimmer line:

• Round line - the most common type, durable and versatile, suitable for general grass trimming
• Square line - has sharp edges that cut thicker grass and weeds more cleanly
• Twisted line - quieter and more efficient, with less drag and vibration
• Star and serrated line - have cutting edges for tougher weeds and thicker growth
• Line diameters - commonly from around 1.3 mm for light electric trimmers up to 3 mm or more for heavy-duty brushcutters
• Line lengths - supplied in small packs, larger coils, and bulk reels

Spools and head parts:

• Spools - hold the line inside the head, available empty or pre-wound with line
• Spool covers - hold the spool in place and protect the head, usually clipping or twisting into position
• Spool springs - push the spool outwards so the line can feed properly
• Bump knobs - screw onto the head and release more line when tapped on the ground
• Eyelets - metal or plastic inserts where the line leaves the head, preventing wear

Trimmer heads:

• Bump feed heads - release more line when the head is tapped on the ground
• Automatic feed heads - release more line automatically as it wears down
• Manual feed heads - require the line to be pulled out by hand
• Fixed line heads - use pre-cut lengths of line that are fitted individually, ideal for heavy-duty work
• Universal heads - designed to fit a range of strimmers using adaptors

Blades:

• Plastic swing tip blades - lightweight blades that pivot on impact, used on some cordless and electric trimmers
• Brushcutter blades - metal blades with two, three, four, or more teeth for thick grass and weeds
• Saw blades - circular blades for cutting small saplings and woody growth

Engine and fuel parts:

• Spark plugs - provide the spark to ignite the fuel
• Air filters - keep dust and grass out of the engine
• Fuel filters and fuel lines - keep fuel clean and flowing to the carburettor
• Primer bulbs - help push fuel into the carburettor for starting
• Starter parts - starter ropes, pulleys, springs, and recoil starters
• Carburettor parts - gaskets, diaphragms, and repair kits

Other parts:

• Guards - protect the user from debris and line
• Harnesses - spread the weight of the machine for comfortable use
• Drive shafts and gearboxes - transmit power from the motor or engine to the head
• Anti-vibration mounts - reduce vibration felt by the user

How to choose the right strimmer parts?

Choosing the right strimmer parts means matching them to the machine and the type of work being done. Work through these points in order:

• Strimmer make and model - identify the brand, model, and model number, usually found on a label on the motor or engine housing
• Original part number - check the original part number in the manual or on the old part, as this is the most reliable way to find the correct replacement
• Line diameter - choose a line diameter that suits the strimmer. Using line that is too thick can overload the motor and stop the line feeding properly, so check the maximum diameter in the manual
• Line shape - choose round line for general use, square or star line for thicker grass and weeds, and twisted line for quieter, smoother cutting
• Spool type - check whether the strimmer uses single or twin line spools, and whether you need an empty spool or a pre-wound spool
• Bump knob fit - for bump knobs, check the thread size, thread direction, and shape, as these vary between models
• Head type - choose a bump feed, automatic, manual, or fixed line head to suit the machine and how you work
• Blade type - check whether the trimmer uses plastic swing tip blades, and choose the correct shape and fitting. For brushcutters, choose a blade suited to the type of growth and approved for the machine
• Engine parts - for petrol strimmers, match spark plugs, filters, and starter parts to the engine model
• Quality and brand - choose good-quality parts from reputable suppliers for a reliable fit and long service life

FAQ - All you need to know about strimmer parts

What size strimmer line do I need?

Check the strimmer manual or the label on the head for the recommended line diameter. Light electric and cordless strimmers often use around 1.3 mm to 1.6 mm line, while petrol strimmers and brushcutters often use 2 mm to 3 mm or more.

Can I use thicker line in my strimmer?

It is not recommended to go above the maximum line diameter for your strimmer. Thicker line can overload the motor or engine, reduce speed, and stop the line feeding properly.

What is the difference between round and square line?

Round line is strong, durable, and suitable for general trimming. Square line has sharp edges that cut thicker grass and weeds more cleanly, but it can wear faster against walls and hard surfaces.

Why does my strimmer line keep breaking?

Common causes include old or dry line, line that is too thin for the job, cutting too close to walls, fences, or stones, or line that is wound incorrectly on the spool.

Why won’t my strimmer feed line?

Common causes include line that is tangled or wound too tightly, a worn or missing spool spring, line that has welded together from heat, a worn bump knob, or line that is too thick for the head.

How do I wind a strimmer spool?

Follow the arrows on the spool to wind the line in the correct direction, keep the line tight and even, and do not overfill the spool. Twin line spools usually need two equal lengths, one in each section.

What is a bump knob?

A bump knob is the part at the bottom of a bump feed head. Tapping it on the ground while the head is spinning releases more line. Bump knobs wear down over time and should be replaced when worn.

What are swing tip blades?

Swing tip blades are small plastic blades used on some cordless and electric trimmers instead of line. They pivot on impact, which helps reduce damage when they hit hard objects.

How do I keep strimmer line in good condition?

Store line in a cool, dark place away from sunlight. Some users soak older nylon line in water before use to help keep it flexible, but it is best to follow the line manufacturer’s guidance.

Is it safe to replace strimmer parts myself?

Most parts can be replaced safely at home. Always switch off and unplug electric strimmers, remove the battery from cordless models, and disconnect the spark plug on petrol models before working on them. Wear gloves when handling blades.