Summary
Choosing a ball transfer unit comes down to load, environment, surface, mounting and orientation.
Follow this five-step selection guide from Alwayse engineers.
To choose the right ball transfer unit, work through five questions in order: how much load each unit must carry, whether the environment is wet or corrosive, whether the items being moved can be scratched, how the unit will be fixed, and whether the ball faces up or down. Those five answers point to a single specification from the Alwayse range of 132 units. This guide takes each step in turn.
Specifying a ball transfer unit is straightforward once you break it down. Get it right and you have a reliable, long-life solution; get it wrong and you risk corrosion, surface damage or premature failure. You can shortcut the whole process with the Brief Builder or the search tool but it helps to understand what drives each decision.
Step 1: Calculate the load per unit
Start with weight. Alwayse units fall into three load tiers, light (0–100kg), medium (101–249kg) and heavy (250kg and above), scaling up to 12,000kg in the heaviest-duty solutions. The load is shared across the units supporting an item, so the figure that matters is the load per unit, not the total. As a rule of thumb a flat item is supported by at least three units; size for the worst case where fewer units bear the weight. The full method is in our guide to calculating load capacity.
Step 2: Assess the environment
Next, consider exposure to moisture and chemicals. A dry indoor line can use carbon chrome steel. Any contact with water, steam, washdown chemicals, salt air or outdoor weather calls for stainless steel, which resists corrosion that would rapidly degrade carbon steel. Cold stores, food lines and marine settings all fall into this category. The material trade-offs are set out in our materials guide.
Step 3: Check surface sensitivity
Then look at what is being moved. Hard steel balls can scratch or mark delicate surfaces. If you are handling glass, polished aluminium, painted panels or coated sheet, specify nylon load balls, which are soft and non-marking. This is standard practice in glass processing and automotive paint-prep lines.
Step 4: Choose the mounting style
Now decide how the unit fixes to the surface. The choice comes down to three practical questions, do you need a flush top surface (drop-in or base fixing), easy removal for maintenance (flanged or threaded stem), or a surface you cannot drill or thread (clamped)? Each option is compared in our guide to mounting types.
Step 5: Confirm orientation: Ball up or ball down
Finally, confirm the orientation. Ball up is the standard arrangement for tables and decks where items sit on top. Ball down is used where the unit supports a load from above, such as under a moving platform. The Brief Builder asks this directly, because it changes which units are suitable.
Putting it together
With those five answers, load, environment, surface, mounting and orientation you have a complete specification. Enter them into the Brief Builder and Alwayse will return matching options, or call the technical team on +44 (0)121 380 4700 for a recommendation grounded in 85+ years of application experience.
Frequently asked questions
How do I know what load rating I need?
Work out the load per unit, not the total weight. Divide the heaviest expected load across the minimum number of units that will support it at any moment, then add a safety margin. Match that figure to the light (0–100kg), medium (101–249kg) or heavy (250kg+) tier.
When should I choose stainless steel over carbon steel?
Choose stainless steel whenever the unit will meet water, steam, washdown chemicals, salt air or outdoor weather, and for all food, pharmaceutical and hygiene-critical settings. Carbon chrome steel is the right, more economical choice for dry indoor use.
Which ball transfer unit is best for delicate surfaces?
Nylon-balled units. Nylon is softer than steel, so it carries the load without scratching or marking glass, polished metal, painted or coated surfaces.