Using Ball Bearing Transfer Casters as Caster Wheels
Ball bearing transfer casters are normally used in the ball facing upwards direction for transferring boxes and materials on conveyors or tables. Here are some examples.
Can a Ball Transfer Bearing Be Used as a Floor Caster Wheel?
Yes, good quality ball transfer bearings can also be used in the downward orientation as low profile caster wheels.
Low Profile - These require significantly less height than standard wheeled casters
Fast and effortless direction changes
Does not develop flats
Supports more weight than standard small casters
Can only be used on very hard surfaces, like concrete.
Surfaces must be smooth, because the ball is small, typically only 1in in diameter, however there are larger balls that will roll on slightly rougher surfaces
Weight is supported at a very small point, so the pressure applied to the floor is high
Which Ball Transfer Casters Work Best as Floor Casters?
I've tried to use inexpensive, cheap ball transfer casters as floor casters, but they don't roll smoothly. They appear to roll ok, until a load is placed on them, then they move erratically and even lock up and drag. I think that the manufactures of these skimp on the amount of ball bearings they use, such that when the caster is facing ball down, all the ball bearings are falling to the side and not supporting the load. Also, the quality and roundness of those bearings may be lower.
The only ball transfer casters I have found that work smoothly as floor casters are USA made, specifically those made by Hudson Bearing company. They are actually not that much more expensive than the cheap ones. They also have felt seals to keep out dirt and dust, which makes a big difference in durability.
Ball Transfer Caster Styles
Standard Flange Mount Ball Casters
These are the most common type and easiest to add on to any flat surface. You can buy them in a case of 10, and they are not expensive.
(Case of 10) Hudson Bearings BT-1CS Two-Hole Flange Mounted Ball Transfer, Carbon Steel, 1" Diameter, 75 lbs Load Capacity
Stem Mount Ball Casters
These have a threaded stem, available in different diameters/thread sizes. Good for through hole mounting and can be spaced closer together than the other styles.
Hudson Bearings SBT-1 Stud Mounted Ball Transfer, Carbon Steel, 1" Diameter, 75 lbs Load Capacity, 1/4"-20 Thread Stem (Case of 10)
Application Examples of Ball Casters
I’ve seen ball casters used for a floating head on plasma cutters. They can be used to set the head down against the metal and roll across the surface, or they can be used to protect the torch tip from hitting the metal.
Image from https://www.productionproducts.net/product/plasma-pro-5-cutting-machine/
Ball casters used on the Maslow CNC Router sled. Link to Document
All the friction reduction solutions I have seen for the Maslow sled are using UHMW sheets or rings attached to the underside of the sled. If you have a vacuum that is pulling between the sled and material sheet, that will also increase the friction. Using a ring of ball transfer casters would significantly reduce friction. Good quality ones have seals that will keep the dust out. You need enough casters so that if a few of them are over cuts, the remaining casters touching the surface will support the sled at the right height.