Simplex Platewheels

What is a simplex platewheel?

A simplex platewheel is a flat, hubless sprocket with a single row of teeth, designed to run with simplex roller chain. Unlike a standard sprocket, which has a raised hub for fixing directly to a shaft, a platewheel is a plain plate with teeth around the outside and a small pilot bore in the centre. This makes it very versatile, as it can be bored to suit a shaft, welded onto a hub, bolted to a flange or drum, or built into a custom part.

Simplex platewheels are the most widely used type of platewheel, found in everything from light-duty mechanisms and agricultural machinery to conveyors and industrial drives. Their plain, hubless design makes them ideal where space is tight, where a custom hub is needed, or where the sprocket must be fixed to another component rather than directly to a shaft.

A typical simplex platewheel has:

• Single row of teeth - matched to the pitch, roller size, and inner width of simplex roller chain
• Flat plate body - a plain, hubless plate that can be machined, welded, or bolted
• Pilot bore - a small starter bore in the centre that can be machined out to the required size
• Steel construction - usually made from a strong, weldable steel, sometimes with hardened teeth

Simplex platewheels are usually described by:

• Chain size - the chain the platewheel suits, such as 06B-1, 08B-1, or 10B-1 for British Standard chain, or 081 and 083 for 1/2 inch pitch light-duty and narrow section chains
• Number of teeth - such as 8, 13, 15, or 20 teeth, which sets the size of the platewheel and the drive ratio
• Pitch circle diameter - the effective working diameter of the sprocket
• Pilot bore - the size of the starter bore
• Tooth width - the thickness of the toothed section, matched to the inner width of the chain

For example, a 15 tooth 081 simplex platewheel has 15 teeth and suits 1/2 inch pitch 081 chain, while a 20 tooth 083 narrow section platewheel suits 1/2 inch pitch 083 chain.

Key features:

• Hubless design - a flat plate that can be bored, welded, or bolted to suit the drive
• Simplex chain compatibility - a single row of teeth for standard roller chain drives
• Pilot bore - can be machined to fit the shaft or hub exactly
• Weldable - can be welded to hubs, drums, and fabricated parts
• Compact - ideal where space is limited or a standard hub will not fit
• Wide range of sizes - available in many tooth counts and chain sizes, including narrow section chains

In simple terms, a simplex platewheel is a flat, hubless sprocket that can be machined, welded, or bolted to create a custom chain drive.

Why are simplex platewheels essential?

Simplex platewheels are essential because many chain drives need a sprocket that does not fit the standard pattern. Standard sprockets have fixed hub sizes and positions, which may not suit custom shafts, drums, or fabricated parts. Platewheels give engineers and repairers the freedom to create exactly the sprocket they need, by machining the bore, adding a hub, or fixing the platewheel directly to another component, while still running with standard simplex chain.

Their main benefits are:

• Design flexibility - can be adapted to almost any drive or mounting arrangement
• Custom bores - pilot bores can be machined to suit any shaft size, with keyways added as needed
• Easy to fabricate - can be welded to hubs, drums, and frames
• Space saving - hubless design fits into tight spaces
• Repair and replacement - ideal for replacing worn sprockets on custom or older machinery
• Wide choice - available for standard, light-duty, and narrow section chains
• Cost-effective - an economical way to create custom sprockets

Simplex platewheels are used across a wide range of industries and applications, including:

• Industrial drives - light and medium-duty chain drives on machinery
• Conveyors - conveyor drives and drums
• Agricultural machinery - drives on implements, drills, balers, and harvesters
• Garden machinery - drives on mowers, cultivators, and other equipment
• Packaging and food machinery - drive and timing systems on production lines
• Light-duty mechanisms - small drives using 081 and 083 chains
• Custom fabrication - sprockets built into drums, rollers, and bespoke machinery
• Maintenance and repair - replacing worn sprockets on existing simplex drives

The main types of simplex platewheels

Simplex platewheels are usually grouped by chain standard, chain size, tooth count, and material.

By chain standard:

• British Standard (BS) simplex platewheels - suit European-style simplex roller chains, such as 05B-1, 06B-1, 08B-1, 10B-1, 12B-1, and 16B-1
• ANSI simplex platewheels - suit American-style simplex roller chains, such as 35-1, 40-1, 50-1, and 60-1
• Light-duty and narrow section platewheels - suit 1/2 inch pitch chains with narrower inner widths, such as 081 and 083 chains, which are commonly used on light machinery, garden equipment, and small drives

British Standard, ANSI, and narrow section chains are not interchangeable, so the platewheel must match the chain exactly.

By chain size:

• 05B-1 (8 mm pitch) platewheels - for compact, light-duty drives
• 06B-1 (3/8 inch pitch) platewheels - for light and medium-duty drives
• 081 and 083 (1/2 inch pitch) platewheels - for light-duty and narrow section chains
• 08B-1 (1/2 inch pitch) platewheels - a popular size for general industrial and agricultural drives
• 10B-1 (5/8 inch pitch) platewheels - for higher power drives
• 12B-1 (3/4 inch pitch) and larger platewheels - for heavy-duty drives

By number of teeth:

• Small platewheels - fewer teeth, used as drive sprockets on motors and gearboxes
• Large platewheels - more teeth, used as driven sprockets to reduce speed and increase torque

By material:

• Steel platewheels - strong, durable, and weldable, the standard choice for most drives
• Hardened tooth platewheels - with hardened teeth for longer wear life in demanding drives
• Stainless steel platewheels - for corrosive, food, and washdown environments

Related products:

• Simplex sprockets - sprockets with hubs, ready to fit directly to shafts
• Weld-on and bolt-on hubs - used to mount platewheels onto shafts with tapered locking bushes
• Simplex chain and links - matching chain and connecting links for simplex drives

How to choose the right simplex platewheel?

Choosing the right simplex platewheel means matching it to the chain, the drive ratio, and the way it will be mounted. Work through these points in order:

• Chain standard - check whether the drive uses British Standard, ANSI, or a light-duty or narrow section chain such as 081 or 083
• Chain size - choose a platewheel that matches the chain pitch and inner width exactly
• Number of strands - make sure the platewheel is simplex, with a single row of teeth
• Number of teeth - choose tooth counts on the drive and driven sprockets that give the required ratio. As a guide, larger tooth counts give smoother running and less chain wear, especially at higher speeds
• Pitch circle diameter - check the platewheel fits the available space
• Bore - check the pilot bore can be machined to the required shaft or hub size, leaving enough material for strength
• Mounting method - decide whether the platewheel will be bored to fit a shaft, welded to a hub, or bolted to a flange or drum
• Load and speed - choose a chain size and tooth count suitable for the power and speed of the drive
• Material - choose steel for general use, hardened teeth for longer wear life, or stainless steel for corrosive environments
• Quality and brand - choose platewheels from reputable suppliers for accurate tooth profiles and reliable performance

How to fit a simplex platewheel

Fitting a platewheel correctly helps the drive run smoothly and accurately:

• Machine the bore - bore the platewheel to the required size, keeping the bore concentric with the teeth, and add a keyway if needed
• Or weld to a hub - if welding to a hub, align the platewheel carefully, tack it in several places, and weld in short runs on alternate sides to reduce distortion
• Or bolt to a flange - if bolting to a flange or drum, drill accurate bolt holes and make sure the platewheel sits flat and true
• Check run-out - make sure the platewheel runs true, without wobble or eccentricity
• Fit to the shaft - secure the platewheel or hub to the shaft with a key, set screw, or tapered locking bush
• Align the sprockets - make sure the drive and driven sprockets are in line and the shafts are parallel
• Fit the chain - fit the simplex chain and set the tension, leaving a small amount of slack on the slack side
• Lubricate - apply suitable chain lubricant before running

FAQ - All you need to know about simplex platewheels

What is a simplex platewheel?

A simplex platewheel is a flat, hubless sprocket with a single row of teeth, designed to run with simplex roller chain. It can be bored, welded, or bolted to suit the drive.

What is the difference between a platewheel and a sprocket?

A standard sprocket has a raised hub for fixing directly to a shaft. A platewheel is a flat plate without a hub, giving more flexibility to bore it, weld it to a hub, or bolt it to another part.

What does the pilot bore mean?

The pilot bore is a small starter hole in the centre of the platewheel. It is designed to be machined out to the required shaft or hub size.

What do 081 and 083 mean?

081 and 083 are chain sizes for 1/2 inch pitch chains with narrower inner widths than standard 08B chain. They are commonly used on light machinery, garden equipment, and small drives. The platewheel must match the exact chain size, as the tooth width differs.

What does narrow section mean?

Narrow section refers to platewheels with thinner teeth, designed to suit chains with a narrower inner width, such as 083 chain.

Can I weld a simplex platewheel?

Yes. Steel platewheels are usually weldable, so they can be welded to hubs, drums, and fabricated parts. Weld carefully to avoid distortion, and check the platewheel runs true afterwards.

How do I mount a platewheel to a shaft?

You can bore the platewheel to fit the shaft and add a keyway, weld it to a hub, or bolt it to a hub or flange. Weld-on and bolt-on hubs with tapered locking bushes give a strong, removable mounting.

Can I use a simplex platewheel with duplex or triplex chain?

No. Simplex platewheels have a single row of teeth and are designed to run with simplex chain only.

What is the difference between BS and ANSI platewheels?

BS platewheels suit British Standard chain, and ANSI platewheels suit American Standard chain. They have different tooth dimensions and are not interchangeable.

How do I work out the drive ratio?

Divide the number of teeth on the driven sprocket by the number of teeth on the drive sprocket. For example, a 15 tooth drive sprocket and a 45 tooth driven sprocket give a 3:1 ratio, reducing speed to a third and increasing torque.

Should I replace platewheels when I replace the chain?

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