Castors & Wheels.

What are Castors & Wheels?

Castors and wheels, also searched for as wheels and castors, casters and wheels or casters and rollers, cover everything in Accu’s range that helps equipment and loads roll: complete castors, spare castor wheels and ball transfers. Each is easy to tell apart: a castor is a wheel already mounted in a fork with a top plate, bolt hole or threaded stem; a spare wheel, sometimes called a roller wheel, is the wheel alone with a bore for an axle; and a ball transfer is a large ball seated on a bed of smaller balls inside a cup. Together they let engineers make equipment mobile, keep existing castors running with replacement wheels and move loads across a fixed surface in any direction.

The castors and wheels in this range are classified under four European standards, EN 12528, EN 12530, EN 12532 and EN 12533, which between them cover furniture, institutional settings and industrial equipment moved at speeds of up to 16 km/h. The range serves manufacturing, logistics, packaging, laboratories and maintenance teams, on everything from trolleys and machine bases to conveyor tables and assembly benches.

How Castors & Wheels Work

In a castor, the load travels from the fixing down the fork to the axle and out through the wheel, with swivel versions steering and fixed versions tracking straight. A spare wheel does the same job inside an existing fork, so it is defined by four dimensions: its diameter, its tread width, the bore that fits the axle and the hub length that fits between the fork legs, with a plain, roller or precision ball bearing inside. A ball transfer turns the idea upside down, mounting ball-up in a table or conveyor bed so the load rolls across the large ball in any direction as it turns on the smaller balls beneath. That makes ball transfers the right choice where the load moves and the support stays put, while castors suit equipment that has to move itself.

A laser cutting cell in a sheet metal shop uses all three. The unloading table is set with 25.4 mm long life ball transfers, each rated at 125 kg, so an operator can slide a cut sheet in any direction to break out the parts without lifting it. Sorted parts then go onto a kitting trolley running on 125 mm swivel and fixed castors with injection moulded polyurethane treads, rated at up to 200 kg each. When those treads eventually wear, the matching 125 mm x 32 mm spare wheel, with a 12 mm bore and a 44.4 mm hub length, replaces the worn wheel inside the existing fork instead of the whole castor.

Materials Castors & Wheels Are Made From

Accu’s castors, wheels and ball transfers are made from engineering-grade metals, polymers and elastomers, each chosen for load, floor protection and the working environment:

• Steel: Pressed steel castor housings from light to extra-heavy-duty, pressed steel wheel centres, the zinc plated bodies of long life ball transfers and the load balls and outer covers of the carbon steel mini ball transfers.
• Stainless Steel: Castor housings for wet and washdown areas, plus the load balls, support balls and threads of stainless mini ball transfers.
• Cast Iron: Forged castor housings and cast wheel centres, including the cast iron centred spare wheels rated up to 1,200 kg.
• Plastic - PUR: Polyurethane in injection moulded, cast and foamed forms, the last used on the 260 mm spare wheels, which are rated Very Good (4 of 5) for noise.
• Rubber: Natural, synthetic and elastic rubber treads on castors and spare wheels, chosen for shock absorption and quiet running.
• Rubber - Natural: Natural rubber tyres on black and blue spare wheels in 80 mm and 100 mm sizes, rated from 50 kg to 152.3 kg.
• Rubber - TPR: A thermoplastic rubber tread used on light apparatus castors and on spare wheels with polypropylene centres.
• Plastic - Nylon: Polyamide castor wheels and spare wheels up to 200 mm, valued for their low rolling resistance.
• Plastic - PUR: Injection moulded, cast and foamed polyurethane treads that balance load capacity with floor protection.
• Plastic - PP: Polypropylene centres on thermoplastic rubber, solid rubber and foamed polyurethane spare wheels, plus solid wheels on light castors.
• Plastic - Phenolic: Hard phenolic and heat-resistant thermoset wheels rated up to 280 °C.
• Plastic - TP: A black wheel option on a handful of stainless steel castors.

Sizes & Types of Castors & Wheels Available

The castors and wheels range covers everything from 14 mm apparatus castors to 260 mm transport wheels and ball transfers, across the following sizes and types:

• Wheel Diameter (D): 14 mm to 260 mm.
• Wheel Width (T): 13 mm to 80 mm.
• Mounting Height (H): 17 mm to 250 mm.
• Approximate Load Capacity: 25 kg to 1,440 kg.
• Fixing Hole Diameter (d): 8 mm to 25 mm.
• Total Width: 21 mm to 75 mm.
• Thread Size: M10 x 25 to M12 x 30 on castors and M2 to M12 on ball transfers.
• Ball Diameter (BD): 4.8 mm to 7.9 mm.
• Ball Diameter (B): 12.7 mm to 39.7 mm.

Castors run from 14 mm to 200 mm and are grouped further in the Castors range by type, from swivel, fixed and braked castors to rubber, plastic, stainless steel, cast iron, heavy-duty and low profile castors. The largest diameters, up to 260 mm, are available as spare wheels only, with bores from 8 mm to 25 mm and ratings from 25.5 kg to 1,200 kg. Mini Ball Transfers fit M2 to M8 studs and carry 5 kg to 30 kg, while Long Life Heavy Duty Ball Transfers come with a plain body or an M6 to M12 stud and carry 25 kg to 500 kg.

Where a fixed, levelled position matters more than mobility, Accu’s range of machine feet may be a better choice.

FAQ

Q: What is the difference between wheels and castors?

A: A castor is a complete assembly: a wheel mounted in a fork or housing with a top plate, bolt hole or threaded stem, ready to fix to equipment. A wheel is just the rolling part, with a tread, a centre and a bore for the axle, used to replace a worn wheel inside an existing castor or to build into a custom bracket. In Accu’s range, castors run from 14 mm to 200 mm and spare wheels from 40 mm to 260 mm, so the largest diameters are available as wheels only.

Q: What are the common sizes of castors?

A: The most common wheel diameters in Accu’s range are 100 mm, 80 mm and 125 mm, which together account for more than half of the castors listed. Lighter equipment typically uses 50 mm to 75 mm castors, compact low profile castors go down to 14 mm and heavy transport frames use 160 mm and 200 mm. Larger wheels roll over joints and debris more easily and generally carry more, but they also raise the mounting height, so the right size balances load, floor and the height the equipment can accept.

Q: Can I replace just the wheel on a castor?

A: Yes, as long as the replacement matches the original in four dimensions: wheel diameter, tread width, the bore listed as Fixing Hole Diameter (d) and the hub length listed as Total Width, so it fits the axle and sits squarely between the fork legs. Accu lists spare wheels from 40 mm to 260 mm with bores from 8 mm to 25 mm, including matching replacements for many of the castors in the range. Replacing just the wheel keeps the housing, plate and fixings in place, so the castor never has to come off the equipment.

Q: What is a ball transfer?

A: A ball transfer is a large load-bearing ball held in a cup on a bed of smaller balls, so a load resting on it can roll freely in any direction. Mounted ball-up in tables, conveyors and fixtures, ball transfers move the load rather than the equipment, which makes them the right choice for transfer tables, assembly benches and loading stations. Accu’s Mini Ball Transfers carry 5 kg to 30 kg on M2 to M8 studs, while its Long Life Heavy Duty Ball Transfers carry 25 kg to 500 kg.

Bespoke Castors & Wheels Manufacture.

High precision, bespoke manufacture of Castors & Wheels to customer specification. State of the art facilities specialising in both small batch prototyping and large scale manufacture.