Custom Steel Wheels

Custom Acorn™ Nylacron™ Wheels

Kingpinless™ Design Benefits
• Reduction in caster failures
• Greater caster service life
• Easier swivel motion
• Eliminates kingpin tightening and maintenance
• Reduced caster shimmy and shake
• Optional top plates, OAH, Hub Lengths and swivel radius, in both USA and Euro standards
Download Kingpinless Casters PDF

Kingpinless Raceway Design Diameters
and Ball Bearing Sizes
4-71K Series (Category 4)
Load Capacity to: 1,800 lb
Raceway: 2-3/8” diameter with 3/8” ball bearings

5-72K Series (Category 5) (shown left)
Load Capacity to: 4,000 lb
Raceway: 2-3/4” diameter with 1/2” ball bearings

6-81K Series (Category 6)
Load Capacity to: 6,000 lb
Raceway: 3” diameter with 1/2” ball bearings

7-90K Series (Category 7)
Load Capacity to: 6,000 lb
Raceway: 4-1/4” diameter with 5/8” ball bearings

8-94K Series (Category 8)
Load Capacity to: 10,000 lb
Raceway: 4-1/2” diameter with 5/8” ball bearings

9-95K Series (Category 9)
Load Capacity to: 20,000 lb
Raceway: 4-1/2” diameter with 3/4” ball bearings

10-98K Series (Category 10)
Load Capacity to: 40,000 lb
Raceway: 7” diameter with 3/4” ball bearings

Hospital / Pharmaceutical / Health Research
Stainless Steel Kingpinless Casters
Stainless Steel Total Lock Brakes
(Leading or Trailing Edge)
Stainless Steel Precision Ball Bearings Wheels:
• Kryptonic™ (shown left)
• Nylon Fiberglass
• Nylon / Pevolon
• Nylacron™ Heat Stabilized Blue
• Nylacron™ Monocast
• Nylacron™ MOS2
• Solid Elastomer
• Stainless Steel
Download Stainless Steel Casters PDF

Epoxy Coated Caster Rigs
Independent laboratory testing shows epoxy coated caster forks virtually unaffected after 500 hours of ASTM B 117-85 Salt Spray Test. Epoxy coating is an attractive alternative to stainless steel casters in some wet applications.

Finishes – Technical Facts
No one likes rust or corrosion. How can we effectively eliminate or control this condition? Methods of dealing with the problem include the proper application of paint, plating or use of powder coating. Stainless Steel can also be employed.

Following are some alternatives and their related benefits:
Stainless Steel
1. Stainless steel is resistant to nitric acid and sulphuric acid.
2. Stainless steel is resistant to many organic acids, including practically all food acids.
3. Stainless steel is not resistant to seawater or photographic solutions.

Zinc Plating or Yellow Zinc
1. Zinc is used-as a protective coating on steel because it is resistant to attack in many environments.
2. Zinc coatings are inexpensive and easy to apply.
3. Zinc plating provides protection against rusting and pitting.
4. In sea water, zinc plating effectively resists rusting in steel.
5. Zinc plating is applied for corrosive industrial service in a thickness not less than .0002 inches.

Chromium Plating
1. Chromium plating is for objects which must not only be protected from corrosion, but also must present a bright and pleasing appearance.
2. Appearance is maintained both indoors and outdoors, and when in contact with precipitation, soap and other cleaning solutions, food products and beverages.

Powder Coating
1. Epoxy Powder coating is a metallic finishing process where thermo setting powders (epoxy) are heat bonded to a metal surface.
2. Powder coating is more corrosion resistant than zinc plating.
3. Epoxy powders provide moderate cost, low maintenance and long lasting protection against most chemically aggressive environments.

1. Zinc Plating failed after 48 hours
2. Dichromate Zinc Plating failed after 72 hours
3. Epoxy Powder C Creating virtually unaffected after 500 hours
Category 4 Swivel Section 4F-YA-08201-S Epoxy Coated Swivel Rig Shown
Download Epoxy Rigs PDF

Dual Seal Precision Ball Bearings with center piece

Nylacron™ Wheels with Precision Sealed Ball Bearings
Nylacron™ wheels (cast polyamide) with precision ball bearings are best used for rollability and moderate side thrust. When larger side thrusts are encountered, double row precision ball bearings can applied in the hub or larger precision bearings can be utilized. The Bearings are pre-lubricated and sealed, thus reducing maintenance costs.

Precision Ball Bearing Wheels are much easier to install than Tapered Bearings and require no maintenance while in use.

The bigger the precision bearing the greater the bearing life for the same load.

Small diameter caster wheels should have large diameter bearings, similar to pallet wheels for easier rolling under load. Sealed precision bearings are shielded to retain the grease and to exclude grit and dust, etc.

Precision bearing wheels are much easier to push or pull and have very low resistance, even under heavy loads. That is, running conditions are excellent right up to the maximum load limit of the wheels.

(Shown left) An inner spacer bushing is used to pre-load the inner races of each bearing and is done on assembly, so further adjustment is not necessary. End caps are provided with all wheels with bearing ID and axle size to match rig hub length.

The wear of the precision ball bearings is so slight, that even under continuous use, they do not require replacement.
Download Nylacron™ PDF

Power Towing Casters
Power towing casters are designed on the assumption that the power towing will take place at speeds up to 7 kph (4.35 mph) and under good working conditions. Above this call Acorn™.

Obstructions
Obstructions, such as curbs and gullies and even relatively small steps, can exert enormous impact loads which can destroy a caster.

Steps such as lift sills, drain covers and joints in concrete slabs present a particular problem if they are not approached squarely. An oblique approach will almost certainly result in the caster turning at right angles to the obstruction instead of turning in such a way as to climb over it. In these situations the destruction of the caster is inevitable.

Towing trailers in train compounds the problem as only one caster may have to withstand the force generated by the mass of the whole train including the tractor.

As Power Towing Becomes More Common...
it is often desirable to tow a number of trucks or trailers one behind another.

Turntable Axles
Turntable axles have often been used for this purpose, but in addition to being costly, they have two disadvantages:
1. If the turntable is at right angles to the axis of the trucks, the stability is greatly reduced.
2. There is a risk of jack-knifing if the trailer stops on a sharp corner.

Casters are becoming very popular for power towing and work satisfactorily provided suitable precautions are taken. It is essential to obviate “cutting-in” as this would prevent the use of the truck trains in narrow gangways.

Experience has shown that if trucks are rigidly coupled together by means of pin couplings at each end they will follow the track most accurately, if the distance from the rigid caster center line to the rear coupling pin is 25%-33% of the total length of the truck from front to rear coupling pins. This can be achieved by moving the fixed casters forward. But this incurs a penalty in that it reduces the wheelbase of the truck and also causes the total weight to be shared disproportionally between the swivel and rigid casters. In order to distribute the weight of the truck and its contents evenly between the front and rear rigid casters, it is advisable to extend the drawbar at the rear of the truck.

Specifically designed power towing casters have tapered roller bearings in both the swivel head and the wheel and will operate satisfactorily at speeds up to 7kph (4.35 mph). Vulkollan™ tread wheels are recommended for this application.
Download Towing Technology PDF

Load Weight
The first consideration of caster selection is to determine the combined weight of the load and equipment. Allowance should be made for uneven distribution of weight, since this can result in one wheel carrying more load than the rest. Mechanical loading can also impose severe shock loading, which adds to the loading factor. Two charts to aid in this selection are: CASTER MOUNTING COMBINATIONS and DETERMINING LOAD RATINGS PER WHEEL. Please note in the load rating chart for extreme conditions, ratings take into consideration uneven floors, curbs and holes in the floor which cause severe impact loads.

Tips on Wheel Selection
In general, the greater the load, the larger the wheel diameter should be for better weight distribution and easier rolling.
• Larger wheels roll easier than small wheels.
• Hard treads roll easier than soft treads.
• Resilient treads roll over rough surfaces more easily than hard treads.
• Larger wheels with larger bearings give longer life and easier rolling.

Electric Conductivity
Insulant materials with a resistivity greater than 1015 ohms, such as plastics, build up a charge by friction. The electrostatic charge is discharged through the body when the object is touched. This can be prevented by the use of electrically conductive (anti-static) wheels, which conduct the charge away or prevent it from building up. Electric conductive wheels have a leakage resistance equal to or less than 104 ohms. Electric conductive rubber tires are subject to 100% quality control inspection, each being tested at 500v DC.

Floor Considerations
All metal wheels will damage floors if the load is heavy. Resilient wheels are not so easy to move, but are floor protective. Remember, it costs more to repair the floor than the wheel running on it. Make sure the wheels selected are large enough to pass over the cracks in the floor, tracks, dock plates, grates, moldings or other obstructions. In some cases, dual wheels are the best for the application. The larger the wheel and the more resilient the wheel, the greater the ability to move over rails and other similar objects.

Rubber & Urethanes
Rubber and Urethanes give maximum quiet and floor protection. Steel is the hardest on floors, thus Nylacron™ is a great compromise - giving moderate floor protection with high weight capacity. For floor protection on linoleum, tile, etc. use cushion neoprene or polyurethane. For carpeted floors, use donut or hi-modulus neoprene or polyurethane.
Other Considerations:
• Noise
• Dirt, chips, threads or other detrimental substances
• Grease, oil, water or chemicals.
• Temperature extremes

Type of Service
Intermittent: Occasionally moved loads, short travel distances or for dollies used to move materials in storage or warehouse operations. Continuous: For continuous service, either manually or mechanically powered, a heavier duty caster with anti-friction bearings is necessary.

Mechanically Powered Trailer-Type
This type operation requires special heavy duty construction with large swivel bearings to withstand the high impact and shocks encountered. Large Precision Ball Bearings should be considered in the swivel for main load bearing and a tapered thrust bearing for side thrusts. Large Precision Ball Bearings are recommended for wheel bearings to take the side thrust loads and higher speeds, as well as being maintenance free.

Institutional
Most institutional application require medium duty casters. In wet applications or for excessive washings, cart washables or stainless steel casters may be required. A lower cost alternative to stainless steel casters could be epoxy-coated rigs with Nylacron™, Nylon, Solid Elastomer or Kryptonic™ Wheels having Stainless Steel Sealed Precision Ball Bearings.
Download Caster Application PDF

Starting Resistance
Starting resistance is the force required to set the wheel in motion from a stationary position.

Rolling Resistance
Rolling resistance is the force required to keep the wheel in constant motion. This resistance is dependent upon the load, wheel diameter, tread material, bearing type, caster offset and floor surface and temperature.

Swivel Resistance
Swivel resistance is determined by the swivel bearing sizes, ball diameters and ball race diameters.

Hard Wheels
Hard wheels will not flatten under load, thus better rollability. However, the hard wheel has difficulty starting with particles, holes or obstacles in or on the floor.

Resilient Wheels
Resilient wheels move more easily over obstruction as they deform and roll over the obstructions. On the other hand a flat area, instead of a line, is in contact with the floor and thus the resistance to rolling is greater.

In general, the larger the wheel, the easier it rolls. Wheels with Precision Ball Bearings carry greater loads and are the easiest to roll. Roller bearing wheels carry heavy loads, but do not roll as easy. When possible, use the largest precision wheel for the best rollability. Any of theses factors have an impact on the mobility and easy handling of the equipment or machine. Listed below is a comparative chart regarding rolling resistance of different type treads

Tractive Resistance
Tractive resistance is the effort required to either push or pull a cart or truck along in a straight line or to maneuver it in confined spaces.

The following table should be an aid to determine how many people are required to move and control a cart or truck in normal workshop conditions.

The above figures are based on roller bearing wheels 8” diameter. Wheels with proper size precision bearing wheels have lower tractive resistance, since they have better rollability.

Tractive Resistance will vary approximately in inverse proportion to the diameter, down to a minimum of 5”. It should be noted that a typical person is capable of maintaining a horizontal force of 26 lbs increasing to about 40 lbs from a standing start.

Urethane wheels if left standing for a long time, could require at least twice the force to initiate movement and its tractive resistance will increase momentarily up to about seven times the figure given above.

Download Rolling Resistance PDF

Main Parameters
The main parameters for determining proper caster loading are rig arrangements and floor conditions. To provide a guide, eight typical truck or cart arrangements are shown below.

IMPORTANT:
Each arrangement shows LOAD RATING PER WHEEL EXPRESSED AS A PERCENTAGE OF THE TOTAL VEHICLE WEIGHT PLUS LOAD WEIGHT for both NORMAL and EXTREME floor conditions.

Example:
4000# load and pattern "6" under extreme conditions means each caster and wheel must be able to take 45% of the total load or 4000 x 45% = 1800#

Precision Bearing Wheels
Precision bearing wheels are recommended for ease of rollability, less maintenance and less downtime for lowest cost-in-use.

Download Load Ratings PDF

Wheel Selection Criteria
Choosing the type of wheel that best suits your application is an important requirement. Each wheel type may have characteristics that make it excellent for one job but unworkable for another. This chart provides general information you may find useful in choosing a wheel. If further guidance is required, please consult the factory.

Other factors to consider in choosing a wheel type include:
• Type of bearings can have a major impact on rollability, durability, maintenance schedules, and capacity.

• Floor conditions: The presence of obstacles, debris, oil and/or chemicals can have a significant impact on the life and performance of a wheel. A general rule is that softer treads are better for obstacle laden floors, floor protection and quiet operation. Harder treads are best for rollability on smooth floors but offer less floor protection and cushioning.

• Maintenance: The expectation that wheels will or will not be properly maintained is another factor in choosing wheels/bearings.

• Manual vs Power Tow: Generally, power tow requires durability and quiet operation, whereas manual operation requires rollability and ease of swiveling.

• Properly matching wheels to specific applications can involve factors too numerous to list completely. Please consult Acorn™ for further information.

Download Wheel Selection / Correction Criteria PDF

CAD Drawings Available for Ever Product
Call Acorn™ toll free 800-523-5474 or e-mail us at acorn@acornindprod.com to obtain specific CAD drawings of the casters, wheels or other products that interest you.