Summary
Ball transfer units are available in five main mounting styles: flanged (bolted via a flat flange), threaded stem (screwed into a threaded hole), drop-in or press-fit (pushed into a drilled hole for a flush finish), clamped (secured externally), and base fixing (mounted from underneath).
Ball transfer units come in five main mounting styles: flanged (bolted through a flat collar), threaded stem (screwed into a threaded hole), drop-in or press-fit (pushed into a drilled hole for a flush finish), clamped (gripped externally) and base fixing (mounted from underneath). The right choice depends on your surface, your access for maintenance, and whether you need a flush top surface. Alwayse offers every fixing method across its 132-unit range.
Mounting style is one of the most practical decisions in BTU selection — it determines installation, ease of replacement and the finished appearance. The comparison below is followed by a detailed look at each option; you can filter units by fixing method directly on the product hub.
| Mounting style |
Flush surface? |
Easy to remove? |
| Flanged |
No |
Yes |
| Threaded stem |
Partly |
Moderate |
| Drop-in (press-fit) |
Yes |
Moderate |
| Clamped |
No |
Yes |
| Base fixing |
Yes — best |
Moderate |
Flanged mounting
Flanged units have a flat collar with two or more bolt holes and are secured with screws through those holes. The bolted connection is extremely secure and resists vibration and lateral force, and it is easy to install, inspect and remove for maintenance — no precision hole is needed, just clearance holes. The trade-off is that the flange sits proud of the surface, so fixings are visible. Flanged units are ideal for heavy-duty tables, high-vibration installations and retrofitting to existing surfaces.
Threaded stem (stud/bolt) mounting
Threaded stem units have a threaded shaft that screws into a tapped hole. They are compact with no flange, present a clean profile with only the housing visible, and are height-adjustable by screwing the stem in or out. They suit conveyor frames, machine tables and jig plates where space is tight. The surface must be thick enough to take the thread, and removal means unscrewing, which is slower than unbolting a flange.
Drop-in (press-fit / interference fit) mounting
Drop-in units are pressed into a precision-drilled hole and held by an interference fit — the housing is fractionally larger than the hole. The result is a completely flush top surface with no visible fixings, fast installation, and nothing to loosen over time. This is the most popular style for purpose-built ball tables. It requires the hole to be drilled to the manufacturer’s tolerance: too large and the unit is loose, too small and the housing can be damaged.
Clamped mounting
Clamped units are held by an external clamp or bracket gripping the housing. No drilling or threading of the surface is needed, units are easy to reposition, and the method suits structural steelwork, rented facilities, prototypes and temporary rigs. It is generally less secure than bolted or press-fit alternatives, so it is not the choice for high-vibration or heavy-load work.
Base fixing
Base-fixed units mount from underneath: the housing passes through the surface from below and is secured beneath. This gives the cleanest possible top surface — no fixings visible, nothing to snag — and a premium finish ideal for high-specification tables and cleanrooms. It requires access to the underside for installation and maintenance, so it is not practical where the surface sits directly on a solid structure.
Choosing the right mounting style
Three questions decide it. Do you need a flush top surface? Choose drop-in or base fixing. Do you need easy removal for maintenance? Choose flanged or threaded stem. Can you drill or thread the surface? If not, clamped is your answer. The Brief Builder will guide you to the right option, or contact the technical team directly.
Frequently asked questions
What is the most popular ball transfer unit mounting style?
Drop-in (press-fit) mounting, because it gives a completely flush surface with fast, simple installation. It is the standard choice for ball tables and platforms.
Can I retrofit ball transfer units to an existing surface?
Yes. Flanged units are easiest to retrofit as they only need clearance holes for bolts. Threaded stem units can be retrofitted where you can tap holes, and drop-in units need precision-drilled holes to the specified tolerance.
What hole size do I need for a drop-in ball transfer unit?
It depends on the model and is given on the product data sheet. Always use the manufacturer’s specified diameter and tolerance — too large and the unit falls out, too small and the housing can be damaged.
Can I adjust the height of a ball transfer unit?
Threaded stem units are height-adjustable — screw the unit further in or out to raise or lower the ball. Other mounting styles have a fixed installed height.