MRO Magazine

Feature

DON’T WAIT FOR THE SQUEAKY WHEEL

The maintenance of casters is an afterthought for many industrial users. However, caster maintenance is very important in every type of organization, and it should be a priority for maintenance and sa...


The maintenance of casters is an afterthought for many industrial users. However, caster maintenance is very important in every type of organization, and it should be a priority for maintenance and safety professionals.

Having a maintenance program and procedures in place to make caster applications safe is actually a critical safety issue. We all know that the squeaky wheel gets the grease, but the wheel should really get the grease long before it squeaks.

Safety and maintenance

Users are responsible for the proper operation and maintenance of the casters on equipment. Some equipment will quickly become damaged and unsafe if abused or subjected to improper demands. If the casters are maintained and not abused, you will get the maximum safety and service performance from them.

Basic precautions of caster applications include:

• Do not overload equipment on casters.

• Do not drop heavy loads on carts or trucks.

• Do not use casters at high speeds.

These actions would create severe impact and shock loads that may lead to caster, wheel or equipment failure.

Check frames and fasteners

To keep casters rolling smoothly, they should be inspected for frame tightness, lubrication, tread wear, free movement of the swivel assembly, and for corrosion or dirt. Periodically turn caster-mounted equipment on its end or side and check the following:

• Look for broken welds or deck boards.

• Tighten loose nuts and bolts.

• Look for equipment frame distortion caused by overloads and impact loads. Distorted frames can lead to wheel failure by placing disproportionate loads on one or two casters.

• If casters are stem types, make sure that the legs of the equipment are not bent and that mounting bolts are securely fastened.

• Always use locknuts or lock washers to mount casters to equipment.

• Make certain casters with expanding adapter stems are held firmly in place in tubular equipment.

• Look for fallen or destroyed grease zerk nipples and replace them.

Caster and wheel lubrication

The lubrication of casters and wheels is essential. The lubrication schedule you use will depend on your specific applications. Normal conditions may warrant lubrication every six months. However, for wet or corrosive environments, monthly lubrication may be necessary.

Lubrication may also be required after each cart washing. Special high-temperature, water-resistant lubricants must be used for these applications. In wet environments, consider using stainless steel casters that require less maintenance, and also use corrosion-resistant models in frequent cart-washing applications.

Caster maintenance and inspection

Check the caster swivel assembly for excessive play due to wear. If the swivel assembly is loose, it is advisable to replace the fork or the entire caster.

If the caster has a king bolt and nut, make sure it is fastened securely. If the swivel does not turn freely, check for corrosion or dirt binding the raceways. Again, it may be necessary to replace the swivel assembly or the entire caster.

When purchasing casters, it is advisable to get casters with swivel head seals pre-installed in both upper and lower raceways. Swivel head seals keep grease in and dirt out of the important swivel raceways.

If the equipment has rigid casters at one end, make sure that the caster fork legs are not bent, distorted or misaligned due to side-thrust forces or impacts during use.

Wheel maintenance and inspection

Check wheels for visible tread wear. Flat spots may indicate the accumulation of floor debris, such as string or thread, which can cause the wheel to bind.

Remove the wheel axle bolt and nut. Clean out foreign material and check the wheel bearings for wear or failure. Re- assemble if the parts are not damaged.

Wheel thread guards may be installed to reduce buildup if string and thread wrapping is a continuing problem. After wheels have been inspected and repaired or replaced, be sure the axle nut is properly tightened. Use lock washers or lock nuts on all axles.

Brake maintenance and inspection

Check brakes for proper operation. It is recommended that scaffold caster brakes be tested daily, or before each use of the equipment. Apply brakes one at a time and attempt to move the equipment to make sure that each brake is not slipping or loose.

If brakes slip due to worn or damaged wheels, replace the wheels immediately and retest the brakes. If the brake mechanism itself is not operating properly, repair or replace it. Before returning the equipment to use, always retest brakes.

Remember, total lock brakes ensure that both the wheel and swivel are firmly locked simultaneously. During inspection, make sure both the swivel head is firmly locked in place and the wheel does not turn at all.

Power-towed operations

Power-drawn equipment, such as in a towline or where mechanically moved by a conveyor, will require casters, wheels and bearings that are specifically designed for this application.

Most wheels and bearings in casters are presumed to operate only at the speed of a fast-paced walk, or at about 3-5 km/h, whereas power-drawn equipment and caster applications generally travel at up to 15 km/h or more. In such cases, it is important to specify correct the bearing and wheel configuration to ensure adequate application-specific conditions.

Make sure you understand the factory recommendation for each specific towing or power-drawn caster equipment application. When it comes to mobile equipment, maintenance professionals have an important role to play in keeping the workplace safe.

Mike Titizian is the marketing manager at Colson Casters Ltd., Cambridge, ON. He can be reached at 1-800-643-5515.