Why Hamilton stakes a 3-year warranty on this platform
Caster warranties are usually 90 days because the failure modes are well-known and the manufacturers don’t want to argue with buyers about whether the floor caused the wear. Hamilton extending to 3 years on the MD line means the failure curve sits well outside that window under typical use. Two design choices make it possible: HPI swivel technology and forged-everywhere construction.
HPI™ Swivel Technology — what changed
Conventional kingpinless casters use either a ball raceway (rows of ball bearings between two raceway tracks) or a unit load bearing (single sealed bearing pre-loaded for the rated capacity). Both work. Both have life limits set by the bearing geometry.
HPI swivel construction replaces the bearing assembly with a stronger raceway platform. The exact specification is proprietary to Hamilton, but the result is documented: longer service life under impact, less swivel drag under load, and the warranty extension that signals Hamilton’s confidence in the math. This is what differentiates MD from competitive kingpinless designs at the same capacity rating.
The MD specification — what’s in every caster
Top plate & swivel construction
- Mounting plate
- 5/8″ thick drop-forged steel
- Legs
- 3/8″ x 5″ precision laser-cut contoured steel
- Weld pattern
- Inside and outside welds to forged horn base
- Swivel
- HPI™ technology (proprietary platform)
- Mount style
- Bolt-on top plate, multiple bolt patterns available
Wheel construction
- Material
- Forged steel (standard) or polyurethane on forged steel core
- Tread profile
- Machined with slight crown to ease swiveling under load
- Bearing
- Dual-row tapered roller
- Diameter range
- 8″ to 12″ standard, custom up to 16″
- Tread width
- 3″ to 5″ depending on capacity
Capacity tiers within the MD line
The MD series spans an order of magnitude in load rating — the 3,000 lb single-wheel build and the 23,000 lb dual-wheel build share the same DNA but different mass. The 8″ forged-steel single-wheel runs 3,000-5,000 lb. The 10″ forged-steel single climbs to 6,500-10,000 lb. The 12″ forged-steel single hits 12,000-16,000 lb. Dual-wheel construction takes the line to 23,000 lb at the top.
Where MD lives in the field
ShipbuildingHull section transfer, propeller shaft staging, generator placement in yard.
Manufactured HousingModule transfer between assembly stations, full-house roll-off to delivery trailer.
AutomotiveBody-in-white transfer, engine assembly platforms, dunnage cart fleets.
AerospaceFuselage section transfer, wing assembly fixtures, GSE equipment moves.
Steel & FoundrySlab transfer cars, mold staging, finished-product roll-out platforms.
Power GenerationTurbine and generator positioning during build and refurbishment.
When MD makes more sense than competitive heavy duty
Pick MD when the 3-year warranty matters more than the lowest sticker price — institutional buyers (defense, aerospace, automotive OEMs) usually run cost-per-year math rather than cost-at-purchase. Pick MD when you need the documentation chain: Hamilton’s material certs and serial-number traceability are accepted by most OEM tooling departments without supplemental review.
Skip MD if the application is intermittent or the load tier is well below 5,000 lb — you’re paying for engineered features that don’t engage at light use. Use a standard Hamilton Workhorse or Champion at lower capacity tiers and reserve MD spend for the platforms that actually need it.
MD series FAQs
What does the 3-year warranty actually cover?Manufacturing defect, bearing failure, and swivel binding under rated load. Wear-out from over-rated use is excluded. The warranty terms are documented on Hamilton’s spec sheet for each SKU.
How does MD compare to Caster Concepts 99 Series?Comparable capacity ratings. MD uses HPI swivel and crowned-tread wheels; 99 Series uses straight roller bearings and 85A soft polyurethane wheels. Hamilton wins on indoor smooth-floor and tooling applications; Caster Concepts wins on debris-heavy and impact-heavy applications.
Polyurethane wheel option on MD?Yes — Hamilton offers Duralast 95A polyurethane on forged steel core as a wheel option on most MD builds. Capacity drops slightly versus forged-steel wheel but floor protection improves.
What’s the lead time on MD?Standard MD configurations typically ship in 1-3 weeks. Custom builds with non-standard plate dimensions run 4-8 weeks.
Maintenance schedule?Annual bearing inspection and re-grease for the tapered roller bearings. The HPI swivel is sealed for life under rated use. Replace wheels as wear pattern indicates — typically 5-10 years on rated floors.
Spec your MD build with Hamilton material certs
Send the platform load, the floor type, and whether you need OEM-grade documentation. We’ll match the right MD configuration and pull certs.
Call 844-439-4335
