Medium Duty

Medium Duty Ball Transfer Units

Our Medium Duty ball transfer units are machined from solid steel bar which is heat-treated to provide a hemispherical wear-resistant chamber within which the recirculating balls can support the protruding, load-bearing main ball. This robust, low-noise design is engineered for applications requiring conventional (ball ‘up’) orientation. Additional options for this range include impact-absorbing top cap options, and additional drain channels where required, making these transfer units the air cargo industry standard.

Low Friction Low Friction
1 : 0,02
Speed Speed
Temperature Temperature
Shock Resistence Shock Resistence
Orientation Horizontal / Up

Orientation Horizontal / Up

Medium-Duty Ball Transfer Units


Medium-duty ball transfer units are machined from a solid steel bar. This is heat-treated to provide a hemispherical wear-resistant chamber for recirculating (small) balls which support the protruding, load bearing, main ball.

Most top caps (covers) are precision machined from solid steel to protect from misaligned items or impact damage during service. Ball units with a main ball of 22mm (7/8”) diameter or larger, incorporate a felt wiper seal to reduce ingress of contaminants and debris.

Series MX, MV and MW air cargo medium-duty ball transfer units omit wiper seals. They are designed for fast-flowing drainage and expulsion of fluids and contaminants via several patented additional drain channels.

MI76 ball units are user-serviceable with replacement service kits available. However other medium-duty ball transfer units are lubricated and sealed for life.

What about wet, dirty operating environments?

Standard material specification utilises a case-hardened ferrous carbon steel housing and chrome steel balls. They are ideal in clean, dry operating environments.

Other arduous operating conditions may require other materials to better suit the environment. 

High temperatures and corrosive environments require stainless steel. As it better resists high heat, chemical and corrosive operating environments:- Stainless Steel Ball Transfer Units (Suffix “SS”). All parts in stainless steel for maximum resistance.

– Suffix “A” stainless steel balls only.

MW30 and MW45 incorporate stainless steel balls and an internal stainless steel liner cup (ball race).

AISI420 stainless steel has a lower hardness than standard materials. So please reduce the maximum carrying capacity as specified.

Why specify plastic balls?

Plastic ball transfer units use softer POM plastic balls made from Delrin (sometimes also referred to as nylon, nylon 66 or acetal) can be specified by adding the suffix “D” (for example M14D).

Whilst the softer plastic material will reduce the load-carrying capacity of the ball unit, it will provide a softer point of contact with the conveyed item and reduce potential marking of delicate or painted surfaces. We also offer ball materials (Teflon, acrylic, phenolic resin, alumina) custom-built for your application.

Save time by using fixing clips

Where only single-sided access to the conveying plane is available, fixing clips provide a convenient, fast fixing method for M and MG series ball transfers. The spring clip can be fitted to punched or laser-cut bores. The spring-clip will compensate for irregularities in bore diameter and ovality. Thus eliminating costly machining of a precise seating bore for ball transfer unit retention.

Clips can be reused and are available in most sizes. Also, consider tolerance rings for retention.

Fitting and mounting options

MSP series

Integral external threaded stud medium-duty ball transfer units with ISO metric threads requiring M6,  M8, M12 or M20 (standard pitch) locking or Nyloc nut.

MS series

Integral square flange fitting medium-duty ball transfer units (top flange fitting) use 4 countersunk set screws to mount to conveying plane.

M series

Low profile, machined drop-in ball units with solid reinforced circular collar. Optional K-clips and tolerance rings for quick fitting where only single-sided access to the conveying plane are available for fitting.

MG series

Solid ball unit without collar, press or plug fixing. High-profile plain bore ball transfer units. Optional K-clips and tolerance rings for easy fixing.

MF series

Base plate fixing, 4-hole flange mount medium-duty ball transfer unit (bottom flange mounted). Requires 4 bolt surface mount fixing.

MI series

Internal (female) metric thread allows single bolt retention of solid steel ball transfer. Dual-sided access of the conveying plane is required.

MM and MN series

Load equalising spring-loaded ball transfers and die lifters. Low profile internal suspension.  Interference or press fit outer casing with (MM Series) or without (MN Series) top flange/ solid collar.


Air cargo ball transfer units – engineered for standard air cargo ball deck and washdown ball platforms. Rapid drain with noise reduction. Imperial and metric fixing options are ideal where single-sided access of the ball platform is available for fitting and replacement.

Why do M series (medium-duty), L series & LP series units all look very similar?

All 3 types are dimensionally equivalent. M series are machined from solid bars so have higher shock resistance and service life. L series and LP series feature in the light-duty range. L series is assembled from stamped pressings and LP series is machined from solid Acyetal bar for resistance to chemical attack.

Why should I consider heavy-duty ball transfers?

If your application requires:

  1. Full load/maximum carrying capacity in the inverted (ball down or castor) position.
  2. Lowest coefficient of friction 1:005 μ (0,5%) breakaway point of inertia. 
  3. Operating temperature less than -30 degrees centigrade (C/F) or higher than 100 degrees
  4. Operating speed greater than 1,5 meters per second (3 feet/second)   
  5. Shock loading – consider spring loaded and pre-stressed spring heavy-duty ball units
  6. Arduous conditions requiring tailored material specifications.

Typical applications

4 x MX30 units are used in each Omnitrack ball skate. These ball transfer skates engage with cantilever supermarket shelving legs allowing entire (laden) aisles with each train section weighing up to 3000 KGS (6720 lbs) each to be moved quickly. Once the train of aisles has been moved, they can be securely locked using the parking brake/locking unit.

MI76 is specially engineered for mining industry pipe stands. A high-profile 3” (76,1mm) ball allows differing pipeline diameter tubing to be handled for assembly and welding. Typical oil, gas and oilfield dirty applications require large debris channels in order to expel dirt and debris easily. Whilst in the most difficult environments for users to reinstate function quickly and on-site in the event of failure. The unit is easily dismantled for user servicing and cleaning within minutes using service kits. MI76 fit all standard 3.5” BSP (British Standard Pipe) pipe and ball stands widespread in fabrication and tube handling industries.

MV30 air cargo ball transfers feature a low-noise moulded scraper cap and patented drain channels allowing improved fast-flow drainage of fluids and debris. 350 KG (800 LBS) load capacity facilitates easy handling of aluminium ULD air cargo pallets over airport ball mats. Precision machined internal bearings and ball race within either 1-3/4” or 45mm diameter cargo ball deck seating holes throughout airport cargo hubs worldwide.

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