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A precision overmolded bearing is an excellent choice when you need a custom wheel, roller or pulley for a new product or when required in limited quantities. Simply put, a standard bearing is overmolded with a plastic tire. The lower cost of tooling of these designs will keep you on budget and using readily available standard bearings will keep you on schedule.
Many features can be incorporated into a custom design that can meet all of the needs of your application.
- Custom profiles
- Corrosion resistance
- Abrasion resistance
- Custom mounting configurations
The wide choice of bearings and plastic resins allow for a custom design that can meet nearly any operating requirement. Stainless steel or plated bearings for challenging environmental conditions, engineering grade resins to survive in high temperatures, resist chemicals and provide superior wear resistance.
Industries that have benefited from precision overmolded bearings include;
- Medical devices
- Food processing equipment
- Commercial interiors
- Industrial equipment
Mark Bos
National Bearings
National Bearings Company provides manufacturers with high value and cost savings for projects that require a sub-assembly with a bearing or stamping at the center of it.
The broad range of our manufacturing capabilities makes sub-assemblies a core part of our business. By working with National Bearings Company, manufacturers are able to increase productivity and profits.
Benefits include:
- Fewer SKU’s to manage and maintain in inventory
- Reduced assembly time and processes
- Just-in-time delivery to your production facility
- Customized packaging for production and service parts inventory
To manufacture and fulfill your sub-assembly requirements; National Bearings has the capability to manufacture:
- Bearings
- Metal stampings
- Injection molded components
- Machined parts
- Hand and robotic assembly
Your engineering and manufacturing teams can achieve cost and time savings by involving National Bearings early in the design process. Brackets, shafts and even aesthetic features can be incorporated to create a labor saving sub-assembly.
For all of your custom sub-assembly applications National Bearings is ready to assist you
Mark Bos
National Bearings
Both ball and needle retainers can be made in metal or plastic. The decision to choose the appropriate material is based on a few factors. The first factor is the operating condition or environment in which the retainer will function.
If the thrust bearing and retainer must operate in extreme heat, corrosion, or high abrasiveness, then the decision will most often be to use metal. Different metals will be selected such as carbon steel, stainless steel or even brass or bronze.
Plastic retainers used where corrosion resistance is important. Also, plastic is used when the part needs to be light-weight. In these applications the operating temperatures are usually close to the ambient temperature.
The second consideration is cost. Often this becomes a function of volume. Both metal and plastic retainers require a certain amount of tooling to manufacture. With metal retainers, you can do single station tooling. Also, low volume tends to be more cost effective in metal. Additionally there are several ways of controlling the tooling costs in high volume runs for metal retainers.
Typically in ball retainers, the decision to go with plastic versus metal is the same. However, in high volumes, plastic tends to be a little lower in overall cost. In needle bearings, plastic is significantly less expensive than metal but there is a design trade-off. In metal needle bearings you can get the needles closer together to carry more load. If the needle bearings are constructed in plastic, the needles have to be spread out and carry less of a load, but the plastic bearings will be cheaper.
National Bearings analyzes each bearing application carefully and presents the options to ensure the highest quality and cost considerations. The facility is fully equipped to produce bearings in different materials in low or high volume runs and offer complete tooling for the application.
Mark Bos
National Bearings
For many Original Equipment Manufacturers, service and replacement parts are significant source of revenue. Large assemblies and custom parts have traditionally been supplied as service parts, but bearings are usually supplied by bearing distributors as MRO. A custom designed bearing offers the opportunity to improve the performance of an OEM’s product and create additional sales as a service part.
A custom bearing can allow equipment designers to optimize the space available and can integrate features that would have typically required additional components. A custom bearing design can improve the assembly process since fewer components are required. As a service part a custom bearing is very difficult to replace with a standard bearing.
For production volumes, custom bearings can be provided in bulk packaging or packaging that presents makes presentation to assembly machines or personnel easier. As service parts, custom bearings can be packaged individually with identification and bar coding for distribution.
Mark Bos
National Bearings
Bearings used in medical device applications have unique requirements because of the extraordinary conditions in which they must perform. Biocompatibility, corrosion resistance and sterilization are just a few of the challenges the bearing must accommodate. Standard bearings are rarely able to survive in medical devices.
Custom bearings designed specifically for the application offer a solution that can meet all of the needs of a medical device. A custom design can fit into a much smaller space than a standard bearing. The number of components needed in a medical device can be reduced through the use of a custom design. Custom bearings work well in low volume durable devices or provide essential cost savings for high production disposable products.
Example: A medical implant manufacturer created a new product which requires a special installation tool. A custom needle thrust bearing made from stainless steel was designed for the tool. Initially the tool needed to be reusable and autoclavable. As the product becomes widely accepted the tool will need to be manufactured as a disposable product and the bearing can be redesigned to reduce costs.
Mark Bos
National Bearings
Angular contact bearings are the most common style of bearing and are widely used because they can support both radial and axial loads. Stamped angular contact bearings are particularly well suited to custom applications.
High volume, low load or low speed applications are ideal products for this style of bearing. Complex features that add functionality and reduce overall product cost can be included in a custom design.
Case Study – Complex drill chuck bearings
Most drill chucks require a bearing to allow the release of a drill bit or tool after it has been tightened during use. A major manufacturer of chucks wanted to meet this functional need and add an aesthetic feature to alert the user when the chuck jaws were fully tightened on a drill bit.
National Bearings was able to produce a stamped angular contact that provides an audible “click,click,click” when the chuck jaws are tightened and smoothly release the tool when needed. The bearing also had to fit into the very small footprint of a chuck body and match perfectly with a plastic housing and several precision machined components.
Maintaining the high quality and consistency necessary for this demanding application is no simple task. Doing so at a cost that allows our customers to remain competitive in a global marketplace is even more important. National Bearings has been able to provide just these kinds of custom bearings to help bring value to many products.
Other industries that can benefit from stamped angular contact bearings
- Solar array OEMs
- Power tool OEMs
- Consumer goods OEMs
Mark Bos
National Bearings
Purchasing managers often consider thrust washers to be nothing more than commodity washers. To clarify, a thrust washer is designed to create a surface that a bearing can roll on or a load can be applied to. To meet this requirement a thrust washer must:
- Be hardened to a hardness that matches the balls or needles
- Have a high surface finish for smooth rolling which reduces friction
- Maintain much tighter dimensional tolerances
Generally a thrust washer has more precise tolerances than a commodity washer, specifically in the thickness, id and od. This helps to ensure the proper operation of the bearing and a secure fit in an assembly. The tolerances are often plus or minus .001 to .002 of an inch.
In contrast, commodity washers are not hardened and have very rough surface finishes. Also, these washers are almost always round in shape. Whereas thrust washers can have cutouts, shapes or slugs. They can also be custom designed to fit into the application.
National Bearings has existing tooling to manufacture more than 500 sizes and shapes of thrust washers and slugs. Also, we have the ability to do the heat treating and surface finishing to produce the highest quality thrust washers.
In addition, National has expanded it’s capabilities to include custom ground thrust washers which have tolerances of .0005 of an inch or less.
Thrust washers are found in a myriad of industries and applications. Here are several areas that are prevalent:
- Power tools
- Automotive
- Agricultural
- Industrial automation
- Medical devices (hospital beds, lift systems)
- Alternative energy (solar and wind)
- Wind turbine accessories and more
Mark Bos
National Bearings
A thrust bearing is a bearing designed to support axial (thrust loads) in an application. Applications can include everything from point of purchase displays to crane pendants. National Bearings manufactures custom thrust bearings that are designed to meet your exact application requirement.
Thrust bearings are typically constructed of 2 or more thrust races or thrust washers and a complement of balls or rollers. In applications with heavy loads and slow speeds, a full complement thrust bearing that has the maximum number of balls/rollers moving freely in the bearing is ideal. In higher speed or lower load applications, a thrust bearing that uses a retainer is preferred.
While a standard or custom thrust bearing may provide an adequate solution, some applications do not require a complete bearing. In this case a thrust retainer or a bearing with a single washer may offer significant savings in both price and the space required.
Thrust retainers are a component of thrust bearings and are designed to hold the bearings/rollers together in the application. If another component in an assembly such as a casting or plate is acting as a race, a retainer may be a perfect fit. The advantage here is that by providing the retainer alone, the part is less expensive. Also, there are labor savings in assembly by dropping in a retainer rather than loading loose balls.
National Bearings is tooled to make more than 250 different sizes of retainer and 500 different sizes of washers and races in both plastic and metal versions.
Industries and products that feature thrust bearings include: power tools, medical devices, transportation, material handling, display/merchandising industry (spinners) and more…
Mark Bos
National Bearings
Many OEM products include rollers, wheels or pulleys to support drawers, guide cables and belts or operate trolley assemblies. Often these are not recognized as bearings but in fact they are. The goal of all of these products is to reduce friction and extend the life of the product.
Often companies that are looking for rollers, wheels and pulleys do not look to a bearing company for solutions. Sometimes companies will manufacture the rollers themselves using a precision standard bearing. More often than not this design is exceeds the needs of the application and needlessly increases costs.
The best approach is to design the right bearing for the product. A bearing that meets the requirements for the life of the product is taking into consideration the load, speed and environmental conditions.
As an example; instead of having to buy a tire, bearing and mounting bolt separately, we provide a complete integrated solution by designing and producing the entire part as a whole. This saves time, money and fits the specification exactly, controlling costs and reducing the number of components that must be purchased.
National Bearings manufacturers many styles of rollers, wheels and pulleys (Radial Bearings):
- Simple & cost effective: A plastic roller assembly with no balls: integrated stud and roller. Ideal for light duty applications
- Moderate duty solution: A plastic outer race, balls and metal or plastic inner race and integrated stud.
- Heavier duty solution: An insert molded outer race, steel balls, steel inner races and integrated stud. Made from carbon, alloy or stainless steels to meet operating conditions.
- Heavy duty: All steel bearing, made from carbon, alloy or stainless steels.
The typical sizes can range from ½ “diameter up to 2” diameter. Other sizes are available up to a maximum of 6” diameter.
Mark Bos
Business Development Manager
National Bearings Company
Often original equipment manufacturers will have difficulty supporting a discontinued product because they are unable to find an obsolete or custom bearing.
To solve the problem, engineers will try to modify the equipment design to use a standard bearing. This often requires expensive modifications and often limits the functionality of the equipment. In some cases, machinists will attempt to build a custom bearing, however, they don’t have the design experience necessary to recreate the bearing. In the end, some companies just give up and are unable to support their product.
Another common problem is sourcing bearings made from exotic materials for high performance or prototype applications. Sometimes a standard thrust or angular contact bearing is hard to find in exotic or specialized materials. Sometimes a specific grade of bronze, stainless steel or polymer has been used and may not be readily available. Defense and military equipment often requires that the material must meet DFARS requirements.
To solve these problems, National Bearings is uniquely setup to manufacture bearings in low volumes that will comply with specifications and requirements for these situations. We can reverse engineer from a worn bearing, an old drawing or basic description of the application to produce a bearing that is an exact match or, offer a functional alternative.
Also, National Bearings has an extensive collection of tooling for old bearing designs, particularly in thrust bearings. Often times we have the only set of tooling left in the USA! If tooling does not exist, we have developed new manufacturing techniques that do not require tooling. These techniques can be applied to old or new products.
The best approach is to contact us to review your obsolete or hard to find bearing design. From there we can research and provide advice on the options available for the application.
Mark Bos
Business Development Manager
National Bearings Co.
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