Ball Transfer Units

What is a ball transfer unit?

A ball transfer unit is a load-bearing component that allows items to be moved smoothly in any direction across a flat surface. Each unit has one large main ball sitting in a hemispherical cup, supported by many smaller balls. When a load is placed on the main ball, it rolls freely on the bed of smaller balls, so the load can be pushed, turned, and positioned easily in any direction with very little effort.

Ball transfer units are usually fitted in groups, forming a ball transfer table or conveyor section. They are widely used in conveyor systems, packaging lines, workshops, and assembly areas wherever products, sheets, boxes, or components need to be moved, turned, or positioned by hand or between conveyors.

A typical ball transfer unit has:

• Main ball - the large ball that carries the load and rolls in any direction
• Support balls - many small balls inside the cup that the main ball rolls on, reducing friction
• Hemispherical cup - a hardened cup that holds the support balls and main ball
• Housing - the outer body that retains the balls and protects the internal parts
• Mounting feature - a flange with bolt holes, a threaded stud, or a body designed to drop into a hole

Key features:

• Omnidirectional movement - loads can be moved in any direction and rotated easily
• Low rolling resistance - very little force is needed to move heavy items
• Precise positioning - ideal for aligning and turning items accurately
• High load capacity - many support balls share the load, allowing heavy items to be carried
• Range of mountings - flange, surface mount, stud, and drop-in designs to suit different installations
• Range of ball sizes - from small balls for light loads to large balls for heavy-duty applications
• Durable materials - available with carbon steel, stainless steel, and nylon main balls

In simple terms, a ball transfer unit is a rolling ball that lets heavy or awkward items glide smoothly in any direction.

Why are ball transfer units essential?

Ball transfer units are essential because many handling tasks need loads to move in more than one direction. Standard roller conveyors only move items forwards and backwards, which makes turning, aligning, and transferring products between lines difficult. Ball transfer units allow items to be pushed sideways, rotated, and positioned precisely, making handling faster, easier, and safer.

Their main benefits are:

• Easy handling - heavy items can be moved and turned with minimal effort
• Improved safety - reduces lifting, dragging, and twisting, lowering the risk of strains and injuries
• Faster workflows - speeds up loading, unloading, sorting, and positioning
• Precise alignment - makes it easy to line up sheets, boxes, and components for processing
• Flexible conveyor design - allows transfers between conveyors and changes of direction
• Protects products - reduces dragging and scraping that can damage items and surfaces
• Low maintenance - simple design with few moving parts
• Versatile - suits a wide range of loads, industries, and layouts

Ball transfer units are used across a wide range of industries and applications, including:

• Conveyor systems - transfer points, junctions, and turning sections between conveyors
• Packaging and distribution - packing benches, sorting tables, and dispatch areas
• Sheet metal and fabrication - machine infeed tables for guillotines, press brakes, and laser cutters
• Woodworking - saw tables and panel handling
• Assembly lines - positioning parts and assemblies at workstations
• Airport and cargo handling - moving containers, pallets, and baggage
• Glass and stone processing - handling large sheets and panels
• Printing and paper - handling paper stacks and rolls
• Machinery and tooling - die handling and tool change tables

The main types of ball transfer units

Ball transfer units are usually grouped by their mounting method, duty, and ball material.

By mounting method:

• Flange mount units - have a flange with two or more bolt holes, allowing them to be bolted onto a table or frame. Two-bolt flanges are common for light and medium duty, while larger units may have more bolt holes
• Surface mount units - sit on top of a surface with a flat flange or dish, giving a low-profile installation
• Dish surface mount units - have a wide, shallow dish-shaped flange that spreads the load and gives a smooth, low-profile surface
• Drop-in units - fit into a drilled or punched hole in a table, held in place by the housing or a flange
• Threaded stud units - have a threaded stud that screws into a tapped hole or is secured with a nut, ideal for quick fitting and height adjustment
• Press-fit units - pushed into a bored hole and held by an interference fit

By duty:

• Light duty units - smaller units for light items, such as boxes, packages, and small parts
• Medium duty units - for general handling of heavier boxes, components, and sheets
• Heavy duty units - larger units with bigger balls and stronger housings for heavy loads, dies, and pallets
• Spring-loaded units - have a spring under the main ball that absorbs shock and allows the ball to drop when a load is lowered, protecting both the unit and the load

By ball material:

• Carbon steel balls - hardened steel balls for high load capacity and general industrial use
• Stainless steel balls - resist corrosion, ideal for food processing, washdown, and wet environments
• Nylon and plastic balls - quieter, lighter, and less likely to mark delicate surfaces, suited to lighter loads

By orientation:

• Ball up - the most common orientation, with the ball facing upwards so loads roll over the top
• Ball down - units mounted with the ball facing down, used on moving equipment that rolls over a flat surface

By ball size:

• Small ball units - such as 12.7 mm and 15.88 mm balls, for light loads and compact spaces
• Medium ball units - around 22 mm to 30 mm balls for general handling
• Large ball units - 38 mm and above for heavy-duty applications

How to choose the right ball transfer unit?

Choosing the right ball transfer unit means matching it to the load, the layout, and the working environment. Work through these points in order:

• Load weight - work out the weight of the heaviest item to be moved
• Number of units under the load - make sure the item is always supported by at least three units, so it stays stable and the load is shared
• Load capacity - divide the load by the number of units supporting it, and choose a unit with a load rating above this figure, allowing a safety margin
• Unit spacing - space the units so that the smallest item is always resting on at least three units. Smaller items need closer spacing
• Load surface - hard, flat, smooth surfaces roll best. Soft, uneven, or fragile items may need closer spacing, smaller balls, or nylon balls
• Mounting method - choose flange, surface mount, drop-in, or threaded stud units to suit the table, frame, or conveyor
• Ball size - choose larger balls for heavier loads and rougher surfaces, and smaller balls for light loads and compact designs
• Ball material - choose carbon steel for general use and heavy loads, stainless steel for wet or hygienic environments, and nylon for quiet running and delicate surfaces
• Shock loads - choose spring-loaded units where loads are dropped or placed heavily onto the units
• Environment - consider dust, moisture, chemicals, and temperature, and choose sealed or stainless units where needed
• Orientation - most units are designed to be used ball up. Check the manufacturer’s guidance before mounting them ball down
• Quality and brand - choose units from reputable suppliers for accurate load ratings, smooth rolling, and long life

FAQ - All you need to know about ball transfer units

What is a ball transfer unit used for?

A ball transfer unit allows loads to be moved smoothly in any direction. They are used in conveyor systems, packing tables, fabrication tables, and assembly lines to move, turn, and position items easily.

How does a ball transfer unit work?

A large main ball sits on a bed of smaller support balls inside a hardened cup. When a load is placed on the main ball, it rolls freely on the support balls, allowing the load to move in any direction with little effort.

How many ball transfer units do I need?

Enough to make sure every item is always supported by at least three units. The exact number depends on the size of the items, the size of the table, and the spacing between units.

How far apart should ball transfer units be spaced?

Space them so that the smallest item being moved always rests on at least three units at once. Smaller items need closer spacing, while large flat items can be supported by wider spacing.

How do I calculate the load capacity I need?

Divide the weight of the heaviest item by the number of units that will support it at any one time, then choose a unit with a load rating above that figure, allowing a safety margin.

Which ball material should I choose?

Carbon steel balls suit general use and heavy loads, stainless steel balls are best for wet, food, or corrosive environments, and nylon balls are quieter and gentler on delicate surfaces.

What are spring-loaded ball transfer units?

Spring-loaded units have a spring under the main ball that absorbs shock when loads are placed on them. The ball can drop under heavy load, helping protect the unit and the item.

Can ball transfer units be mounted upside down?

Some units are designed for ball-down mounting, but most are designed to be used ball-up. Mounting a standard unit ball down can allow dirt to collect and reduce performance, so check the manufacturer’s guidance.

Do ball transfer units need lubrication?

Most units are designed to run with little or no lubrication. If lubrication is used, a light oil is usually better than grease, which can attract dust and dirt. Follow the manufacturer’s recommendations.

Why is my ball transfer unit not rolling smoothly?

Common causes include dirt, dust, or debris inside the unit, damaged or worn balls, overloading, or corrosion. Clean the unit, check for damage, and replace worn units.

How do I keep ball transfer units working well?

Keep them clean, avoid overloading, protect them from dust and debris, and inspect them regularly for damage, wear, or stiff rolling. Replace any units that no longer roll freely.