Simplex Chains

What is simplex roller chain?

Simplex roller chain is a power transmission chain with a single row of rollers. It is the most widely used type of roller chain, transmitting power between sprockets on parallel shafts in everything from light machinery and agricultural equipment to conveyors and general engineering drives. Simplex chain is strong, efficient, simple to fit, and available in a wide range of sizes, making it the first choice for most chain drives.

Roller chain works by meshing with the teeth of sprockets. As the drive sprocket turns, its teeth pull the chain along, and the chain in turn drives the sprocket on the driven shaft. Chain drives give positive drive with no slipping, so they are accurate, reliable, and efficient.

Simplex chain is made up of alternating inner and outer links:

• Inner links - made up of inner plates, bushes, and rollers. The rollers turn on the bushes and engage with the sprocket teeth
• Outer links - made up of outer plates and pins. The pins pass through the bushes, allowing the chain to flex as it wraps around the sprockets
• Connecting link - a removable link used to join the chain into a continuous loop

Simplex roller chain is usually described by:

• Chain size - such as 06B-1, 08B-1, 10B-1, or 12B-1 for British Standard chain, or 35-1, 40-1, 50-1, or 60-1 for ANSI chain. The 1 shows it is simplex
• Chain standard - British Standard (BS) or American Standard (ANSI)
• Pitch - the distance between the centres of adjacent pins, such as 3/8 inch, 1/2 inch, 5/8 inch, or 3/4 inch
• Length - often supplied in standard lengths, such as 5 metres or 10 feet, which can be cut to size
• Quality and material - such as standard duty, heavy duty, premium, nickel plated, or stainless steel

For example, 06B-1 BS simplex roller chain has a 3/8 inch pitch and a single strand, and is made to British Standard dimensions, while ANSI 40-1 simplex chain has a 1/2 inch pitch and is made to American Standard dimensions.

Key features:

• Versatile - suits a huge range of drives, from light-duty to industrial
• Positive drive - no slipping, giving accurate and reliable power transmission
• High efficiency - transmits power with very low losses
• Strong and durable - handles heavy loads, shock, and continuous operation
• Flexible layouts - drives over long and short centre distances, and can drive several shafts at once
• Supplied in lengths - can be cut to the length needed and joined with connecting links
• BS and ANSI sizes - to suit British Standard and American Standard sprockets

In simple terms, simplex roller chain is a single-strand chain that transmits power reliably between sprockets in a wide range of machines.

Why is simplex roller chain essential?

Simplex roller chain is essential because chain drives are one of the most reliable and cost-effective ways to transmit power. Unlike belts, chains do not slip, so they keep timing accurate and transmit high torque even at low speeds. They can work in dirty, dusty, and outdoor conditions, run over long centre distances, and drive several shafts from one sprocket. Simplex chain offers all these benefits in the simplest, most economical form.

Its main benefits are:

• Positive drive - no slipping, keeping drives accurate and reliable
• High efficiency - transmits power with very little loss
• High torque at low speed - ideal for slow, heavily loaded drives
• Works in tough conditions - suits dust, dirt, heat, and outdoor use
• Long centre distances - can transmit power between widely spaced shafts
• Easy to install and repair - can be cut to length and joined with connecting links
• Cost-effective - economical to buy, fit, and maintain
• Widely available - standard sizes make replacement chain and sprockets easy to source

Simplex roller chain is used across a wide range of industries and applications, including:

• General engineering - drives on industrial machinery
• Agricultural machinery - drives on drills, balers, harvesters, spreaders, and implements
• Conveyors - conveyor drives and transfer systems
• Packaging and food machinery - drive and timing systems on production lines
• Garden machinery - drives on mowers, cultivators, and other equipment
• Doors, gates, and lifting equipment - chain-driven openers and mechanisms
• Printing and textile machinery - drive and timing systems
• Material handling - transfer and handling equipment

The main types of simplex roller chain

Simplex roller chain is usually grouped by standard, quality, material, and finish.

By chain standard:

• British Standard (BS) simplex chain - made to British and European dimensions, such as 05B-1, 06B-1, 08B-1, 10B-1, 12B-1, and 16B-1. Widely used on European machinery
• ANSI simplex chain - made to American Standard dimensions, such as 25-1, 35-1, 40-1, 50-1, 60-1, and 80-1. Widely used on American and international machinery

British Standard and ANSI chains of the same pitch are not interchangeable, as their roller diameters, inner widths, and plate dimensions are different. They also need matching sprockets.

By quality:

• Standard duty chain - for general drives and everyday use
• Heavy duty chain - with thicker plates or stronger components for higher loads and shock
• Premium chain - made to tighter tolerances with improved materials and treatments for longer wear life and greater reliability

By material and finish:

• Plain steel chain - the standard choice for general use, usually supplied pre-lubricated
• Nickel plated chain - offers improved corrosion resistance for damp environments
• Stainless steel chain - resists rust and corrosion, ideal for food, marine, and washdown environments

Common pitches:

• 1/4 inch - such as ANSI 25-1
• 3/8 inch - such as 06B-1 and ANSI 35-1
• 1/2 inch - such as 08B-1 and ANSI 40-1
• 5/8 inch - such as 10B-1 and ANSI 50-1
• 3/4 inch - such as 12B-1 and ANSI 60-1
• 1 inch - such as 16B-1 and ANSI 80-1

Related products:

• Simplex links - connecting links, cranked links, and repair links for simplex chain
• Simplex sprockets - sprockets with a single row of teeth to suit simplex chain
• Tension sprockets and tension arms - to keep simplex chain at the correct tension
• Chain tools - chain breakers and pullers for cutting and fitting chain
• Chain lubricants - to reduce wear and extend chain life

How to choose the right simplex roller chain?

Choosing the right simplex chain means matching it to the sprockets, the power, and the conditions of the drive. Work through these points in order:

• Chain standard - check whether the drive uses British Standard or ANSI chain and sprockets. This is often stamped on the chain plates
• Pitch - match the chain pitch to the sprockets
• Number of strands - make sure the sprockets are simplex, with a single row of teeth
• Power and speed - check the chain can transmit the power at the drive speed, using the manufacturer’s power rating tables. If simplex chain is not strong enough, consider duplex or triplex chain
• Shock loads - consider heavy duty or premium chain for drives with shock loads, frequent starts, or reversing
• Length - work out the number of links needed for the sprocket sizes and centre distance, ideally using an even number of links
• Environment - choose nickel plated or stainless steel chain for wet, food, or corrosive environments
• Lubrication - plan how the chain will be lubricated, as this has a major effect on wear life
• Quality and brand - choose chain from reputable manufacturers for accurate dimensions, strength, and long wear life

How to fit simplex roller chain

Fitting simplex chain correctly helps it run smoothly and last longer:

• Isolate the drive - switch off and isolate the machine before starting work
• Check the sprockets - make sure the sprockets are in good condition, aligned, and securely fixed. Replace worn sprockets when fitting new chain
• Cut the chain to length - use a chain breaker to remove pins and shorten the chain to the required number of links
• Join the chain - wrap the chain around the sprockets and join the ends with a simplex connecting link, fitting the spring clip with its closed end facing the direction of travel
• Set the tension - adjust the chain so it has a small amount of slack on the slack side, as recommended by the chain manufacturer
• Check alignment - make sure the sprockets are in line and the shafts are parallel, so the chain runs straight
• Lubricate - apply suitable chain lubricant before running
• Check after running - recheck tension after a short running-in period, as new chains can settle

FAQ - All you need to know about simplex roller chain

What is simplex roller chain?

Simplex roller chain is a power transmission chain with a single row of rollers. It is the most common type of roller chain, used on a wide range of machines and drives.

What does the 1 in 06B-1 mean?

The 1 shows the chain is simplex, with a single strand. For example, 06B-1 is simplex, 06B-2 is duplex, and 06B-3 is triplex.

What is the difference between BS and ANSI chain?

BS chain is made to British and European dimensions, and ANSI chain is made to American dimensions. Even at the same pitch, they have different roller diameters and widths, so they are not interchangeable and need matching sprockets.

How do I measure chain pitch?

Measure the distance between the centres of two adjacent pins. For example, 08B-1 and ANSI 40-1 chains both have a 1/2 inch pitch.

How do I know which chain I have?

Check the markings on the chain plates, which often show the size and standard. If there are no markings, measure the pitch, roller diameter, and inner width, and compare them with a chain chart.

Can I cut simplex chain to length?

Yes. Simplex chain is supplied in standard lengths and can be shortened using a chain breaker to remove pins. Join the ends with a matching simplex connecting link.

Why should a chain have an even number of links?

An even number of links allows the chain to be joined with a standard connecting link. An odd number needs a cranked link, which reduces chain strength.

How tight should simplex chain be?

The chain should have a small amount of slack on the slack side, as recommended by the manufacturer. A chain that is too tight increases wear on the chain, sprockets, and bearings, while a chain that is too loose can whip and jump teeth.

How often should simplex chain be lubricated?

It depends on the speed, load, and environment. Chains in regular or heavy use need frequent lubrication, while light-duty chains may need less. Follow the chain manufacturer’s guidance.

When should simplex chain be replaced?

Replace the chain when it has stretched beyond the manufacturer’s wear limit, commonly around 2% to 3% elongation, or if links are stiff, cracked, or damaged.

Should I replace the sprockets with the chain?

It is good practice to check the sprockets whenever the chain is replaced. Worn sprockets with hooked or pointed teeth will wear new chain quickly and should be replaced at the same time.

When should I use duplex or triplex chain instead of simplex?

Use duplex or triplex chain when a simplex chain of the same pitch cannot carry the required power, and moving to a larger pitch would need sprockets that are too large or would run less smoothly.