How to Choose the Right Caster and Wheel for Your Application.
With some 20,000 variations available, choosing the right casters to move an auto assembly line, or haul an airplane fuselage, can be overwhelming. We're here to help with selection tips, tricks and advice on which caster and wheel you need for the job.
For your consideration: 6 critical factors
Casters and wheels come in a various shapes, sizes and materials to match unique performance requirements. Some roll on tracks and temperatures up to 500 F. Others bear 40,000-pound loads inside and outside the factory. Choosing the right one will prevent downtime and excessive maintenance.
1. Rollability: it's all in the ergonomics
Ergonomic considerations are always top of mind. As the U.S. workforce ages and becomes heavier, it becomes more susceptible to workplace injuries. That's why employers seek tools and equipment, such as casters and wheels, to reduce stress on joints, prevent back injuries, and better accommodate staff.
Wheel size is the single biggest factor in rollability. Larger wheels are easier to push or pull under load. Even when wheel capacity well exceeds what the load requires, larger diameters help keep workers safe.
Test data is available to determine what size and tread type is best for any given load and ergonomic parameters. It's also true that harder wheels are generally easiest to move, but they can also create noise problems. Hamilton offers many polyurethane tread types to choose from, some specifically aimed at ergonomics. If load cushioning is critical, there are softer treads available. And, spring-loaded casters that provide cushioning without sacrificing ergonomics.
2. Capacity: avoid heavy miscalculation
What's the weight of the load plus the cart, trailer or AGV? What about the possibility of overload, shock loading, abuse or poor floor conditions? It may seem obvious to divide the maximum load weight by four (or however many casters or wheels), but this can lead to heavy miscalculations. Why? Because most loads don't maintain an even weight across the length and width of the vehicle. An off-center load could overload even the most durable casters.
3. Shock loading: prepare for impact
Shock loading occurs when a load is dropped onto the trailer. Or when a rig rolls over a bump, like a concrete joint, door jam, dock plate or leveler. In some cases, shock loading can force a wheel to bear more than three times the weight of the load.
Uneven floors, slopes, ramps or inclines can cause shock loading when one or more wheels lose contact with the floor. In these cases, the remaining wheels must carry the entire load.
4. Operating environment: temperature, noise, moisture and more
Where's it rolling? Environmental conditions must be considered when choosing a caster or wheel. For example, if excessive noise is an issue, Hamilton offers quiet-rolling wheels with high load capacities.
What about the temperature? Extremely hot or cold applications may require special caster and wheel materials, and bearing lubricants, to withstand the conditions.
Moisture can also wreak havoc on metal parts, including bearings, and also on some wheel materials such as polyurethanes. Chemicals present either on the floor or in the work environment require wheel and caster materials. Excessive dust or dirt? We suggest casters and wheels with sealed bearings. Continuous-duty applications are best suited to certain bearing types in the wheels.
5. Abuse: know your crew's tendencies
Abuse takes a toll on casters. We like to believe that everyone uses them as intended, but we also understand that's not always the reality. Sometimes workers move too quickly, take short cuts, or even take out frustrations on them. Keep this in mind when selecting equipment.
6. The effect of floors on wheels, and vice versa
Poor floor conditions can cause a caster or wheel to fail, but don't underestimate the effect wheels can have on floors, too. Very hard wheels, such as cast iron or forged steel, roll easily and carry higher capacities than resilient tread wheels. But, they can damage concrete floors and lead to costly repairs. Most resilient wheels absorb chips and metal shavings into their treads. These can dislodge in other parts of the facility and create housekeeping challenges or hazards.
Recommended accessories: customize to your liking
Optional attachments, such as swivel locks, wheel brakes, swivel assembly and wheel bearing seals, thread guards, keyways and floor truck locks make casters safer, more versatile, or more efficient for certain applications.
You have questions. We have answers.
There's a caster for everyone. Email a sales engineer to find the one that matches your application, or call 888-699-7164.
A guide to Hamilton's swivel constructions
The following swivel constructions are ranked by load capacity: high to low.
For our highest rated production caster series (Ultra Maxi-Duty) with load carrying capacities ranging from 17,000 to 40,000 pounds. It features two precision thrust ball bearings. The outer thrust bearing measures 13 inches in diameter and boasts an impressive 234,000 pounds load rating. And the inner thrust bearing measures 7 inches in diameter with load rating of 100,000 pounds. A third highly specialized four-point contact bearing supports the 1.5-inch diameter integral kingpin.
Our famous swivel technology: Hamilton Precision Integrated. It outperforms conventional CNC-machined ball raceways, kingpinless and unit load-bearing swivel constructions. This design improves the bearing's element of contact and more than doubles the number of contact points. The new HPI™ raceways are also 45% harder than conventional hardened raceways. Features an incredibly smooth 16-micro-inch surface finish. Available in these series: MD, MDD, EPSD, EHD, EHS.
Hamilton's new line of no-maintenance casters. Spinfinity features a maintenance-free, swivel kingpinless construction that's custom CNC machined to host a large internal seal. Made from nitrile butadiene rubber (NBR), the seal is completely enclosed inside the swivel assembly. That's how it keeps grease in and contaminants out.
Extra-thick forgings and Hamilton's proven kingpinless swivel technology boost durability, and extend the life of the casters.
The top plate and inner raceway are one forged steel piece, not a weldment, which provides unmatched strength for shock loading. The raceways are CNC-machined and then hardened to a uniform depth to ensure smooth swiveling under heavy loads. Available in these series: ZFWH, ZFHS, ZFFM.
Commercial Load and Precision Thrust Bearing
A set of hardened and polished steel balls rotates in a CNC-machined raceway. Precision tapered roller bearings absorb radial thrust. Features Hamilton's integrally forged kingpin that's guaranteed for life not to bend or break. Available in these series: WH, HS, FM, CH, 7000, 7100, 7200, 7500, 7700.
Double Ball Raceway
Two sets of hardened and polished steel balls rotate in machined or pressure-coined raceways. The upper raceway absorbs direct thrust, while the lower raceway surrounds the kingpin to absorb side forces (component thrust). Raceways are hardened to match the load rating. Offered with bolt or rivet kingpins. Available in these series: 52, MS, GS, STA, WW.