Tag Archive: bronze gear blanks

  1. Materials Spotlight: 917 Tin Bronze

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    Accurate Specialties has been an industry leader in the manufacture of bronze gear blanks in North America since our establishment in 1987. We are pleased to operate as a full-service bronze foundry, and offer support from the beginning of the design process through completion of precisely machined, ready-to-use bronze gear blanks.

    917 Tin Bronze Properties

    917 Tin Bronze is a copper-tin alloy with a particularly high tin content that is frequently used in applications with low speeds and heavy loads. 917’s particular strength, corrosion-resistance, high ductility, and low-wear capabilities make it an excellent option for a number of parts and components, including:

    • Worm and comprise gears
    • High strength bushings
    • Bearings for heavy loads and low-speed applications
    • Steam fittings
    • Piston rings
    • Valve bodies
    • Pump impellers

    Superior 917 Tin Bronze Gear Blanks from Accurate Specialties

    Centrifugally cast bronze gear blankAt Accurate Specialties, we are pleased to provide high-quality, fully machined bronze gear blanks, including gear blanks made from 917 Tin Bronze. With over 30 years of dedicated bronze casting experience, we are North America’s leading bronze gear blank manufacturer. Accurate Specialties is proud to be ISO 9001:2015 certified, so we can guarantee the best in bronze casting products and services. Our specialties include chill casting, centrifugal casting, spuncast gear blanks, and continuous casting.

    Attributes of Bronze Alloys

    Bronze is an alloyed metal typically composed of copper blended with tin. It can also be produced by alloying copper with other metals, such as aluminum and manganese, depending on its intended use.

    Bronze has been employed by humans in a wide range of applications for thousands of years. Bronze was eventually replaced by iron alloys due to the ready availability of iron, but its overall useful characteristics make bronze a commonly used alloy to this day. Bronze is used to make all manner of everyday objects, such as:

    • Sculptures and musical instruments
    • Decorative medals
    • Electrical products
    • Bellows in appliances and HVAC equipment
    • Springs and washers
    • Industrial components
    • Nautical equipment

    As with all alloys, bronze comes in a number of different alloys and grades. The percentage of copper to other metals in the alloy can be adjusted to meet the needs of a given applications.

    Tin bronze, in particular, is valued for its high tensile strength, low lead content, fine-grained texture, friction resistance, and high resistance to fatigue. Its high corrosion resistance makes it useful in marine and chemical applications where iron-based alloys might rust or corrode. In addition, tin bronze’s high ductility ensures that it retains shape even under high stress and repeated pressure.

    The Accurate Specialties Advantage

    Our state-of-the-art equipment and highly trained specialists ensure that our customers receive the best possible service from engineering design through the completion of the manufacturing process. We offer a high degree of flexibility and our integrated and responsive manufacturing techniques ensure that products are completed to even the most exacting specifications.

    With our top-of-the-line vertical turning center, we are capable of producing large-scale bronze gear blanks with exceptional speed and accuracy, thereby reducing the overall cost of production. In addition to our primary manufacturing services, we are pleased to provide finishing services, including drilling and hole tapping, so that our customers receive finished and ready-to-use products.

    For more information on our exceptional bronze casting products and services, please contact us or request a quote today.

  2. Advantages of Centrifugal Casting

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    When it comes to manufacturing gear blanks, centrifugal casting holds several advantages over other methods.

    The process involves pouring molten metal into a rapidly spinning mold cavity. The force produced by the mold’s spinning forces the material to conform to the shape of the mold. Additionally, extreme pressures that form within the casting device drive material contaminants to the center of the casting, allowing them to be easily removed in future finishing operations.

    Advantages of the Centrifugal Casting Process

    There are a number of advantages to using centrifugal casting for the manufacture of cylindrical and circular parts, such as:

    • Greater strength. The greater strength of parts produced using centrifugal casting is a result of higher density grain structures. As the process allows for more control over directional solidification, the grain structure is more uniform and its mechanical properties are almost equal in all directions. This higher structural density increases the life span of the component and allows for higher stress tolerances. Another factor that contributes to the enhanced part strength is higher product purity, which eliminates internal porosity and improves structural uniformity.
    • Increased product purity. During the casting process, the spinning of the mold places extreme pressures on the molten material. This pressure causes lighter contaminants and impurities to separate from the denser metal. These impurities gather in the bore of the component, minimizing the risk of formation of weak points or areas of porosity within the metal structure. The machining process following casting removes these impurities, leaving a highly pure end-product.
    • Better production cost-efficiency. Increased product purity also affects production cost-efficiency. As impurities gather at the interior surface of the part and are machined out, there is a reduction in the number of defective parts and rejects. The lack of porosity produced through the centrifugal casting process also allows manufacturers to use less metal and produce less material waste. In addition, faster setup and shorter production cycle times lead to improved production cost-efficiency.

    Limitations of Centrifugal Casting

    Although centrifugal casting offers several manufacturing advantages, the process is limited in its production capabilities. Some of the limitations of centrifugal casting include:

    • Size. To avoid the creation of a parabola at the bottom of the casting—which increases machining time—the height-to-diameter ratio used in vertical casting is 2:1. This requirement limits the size of the produced part. In some cases, horizontal casting provides the solution to these limitations​.
    • Internal diameters. Designs with smaller internal diameters also pose a challenge for centrifugal casting operations. The purity and strength advantages of centrifugal casting decrease as the inside diameters of the components decreases. The issue stems from the higher RPMs required to produce the necessary G forces to form the cast product. Although these speeds are possible, there are significant safety issues related to operating at higher RPMs.
    • Shape. The centrifugal casting process only provides production advantages to parts with a cylindrical geometric shape. Although other mold shapes are possible, the loss of the structural and purity benefits and the additional cost of the unique die and post-processing operations make its use impractical outside of producing cylindrical shapes.

    Additional Casting Services From Accurate Specialties

    At Accurate Specialties, we offer a broad range of casting capabilities. In addition to centrifugal casting, we provide:

    • Spin casting. This type of casting allows for the production of parts with high material purity and consistent weight and density. Additionally, when used for the manufacture of bronze gear blanks, the process creates stronger bonds between the gear tooth and hub.
    • Chilled casting. This casting method produces cast products with tight grain structures and outstanding uniformity. These properties result from pouring molten bronze into an aluminum or steel mold, which is at a significantly lower temperature, producing a rapid cooling or “freezing” effect.
    • Continuous casting. Continuous is cost-effective for large volumes of simple parts. It produces parts with favorable mechanical properties, even distribution of alloy agents, and better machinability, friction, and wear properties. The process involves pouring molten bronze alloys through a graphite mold, cooling them into 12-foot bars, and cutting them into “pucks” for further formation.

    Bronze Centrifugal Casting Solutions From Accurate Specialties

    For the manufacture of cylindrical and circular parts, centrifugal casting offers several advantages, including greater part strength, higher product purity, and better cost-effectiveness.

    At Accurate Specialties, we utilize several casting methods—including centrifugal casting—to produce high-quality bronze gear blanks for our customers. Our solid bronze gear blanks are available in diameters ranging from 1–50 inches.

    To learn more about our centrifugal casting solutions, contact us or request a quote today.

  3. What to Know About Chill Casting & Bronze Gear Blanks

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    To achieve greater uniformity and a finer grain structure in gear blanks, Accurate Specialties Inc. uses a special form of bronze alloy casting known as chill casting. This process allows us to produce gear blanks that require less machining and are therefore more cost effective for our customers.

    Our world-class manufacturing capacity allows us to produce chill-cast bronze gear blanks in all shapes and sizes according to our clients’ design specifications. Along with producing near–net-shaped gear blanks, we incorporate precision CNC machining services for keyway cutting, and we also provide our customers with ready-to-hob gear blanks.

    What Is Chill Casting?

    When chill casting, workers pour molten alloys into a steel or aluminum die base. Because the die base is significantly cooler than the poured metal, the alloy rapidly “freezes,” chilling from the outside inward. Referred to as directional cooling, this process results in a finer grain structure and exceptional uniformity in the finished product.

    Metalworkers most commonly use chill casting to form nonferrous billets and ingots. In these applications, this process yields several advantages over sand casting:

    • Direct chill casting allows you to retain the mold after use
    • Chill-cast materials solidify much faster than those created using other means
    • Chill casting produces a tighter material structure in the finished product, resulting in products that are less porous, more accurate, and of higher quality than those created via other methods

    Accurate Specialties uses chill casting to produce bronze gear blanks that incorporate these benefits. Most often, this method is applied to non-symetrical shapes such as sector gears.  These advantages reduce product costs, shorten turnaround times, and reduce machining.

    Gear Blank Manufacturing

    Workers prepare gears for machining by starting with a gear blank, usually a turned casting or forging.

    Forging uses thermal and mechanical forces to alter the shape of solid material into the desired conformations. The metallurgical and crystallization processes that occur during heating and forming strengthen or temper the metal, making it stronger and less porous. Steel and steel alloys are among the most common materials used in this process.

    On the other hand, casting refers to the process by which workers pour molten material into die bases and allow it to harden into the desired shape. This process enables the production of components that are large, intricately detailed, complicated in design, or otherwise unsuited for forging. Casting also allows metalworkers to use a larger range of alloy choices, and finished products tend to require less tooling.


    Accurate Specialties produces a range of solid bronze and composite worm gear blanks for North American markets. We’ve focused on developing top-quality bronze gear blanks for the last 25 years, and our products have gone on to see uses in a wide range of industries.

    At Accurate Specialties, we can:

    • Produce gear blanks from 1” to 50” in diameter
    • Cast pour weights of up to 6,000 lbs.
    • Use our in-depth knowledge of the broad range of bronze alloys that we stock to find the perfect metal for your needs
    • Perfect designs and metal compositions in our state-of-the-art materials lab
    • Perform a wide range of CNC machining processes

    We produce industry-leading centrifugal-cast, chill-cast, and spuncast composite gear blanks, and we’ve also perfected the design of continuous cast bar blanks and shafts. Accurate Specialties provides components for a wide variety of applications in industries including:

    • Automotive manufacturing
    • Power transmission
    • Marine manufacturing
    • Tooling production
    • Oil drilling

    What Can Accurate Specialties Do for You?

    We produce top-of-the-line chill-cast gear blanks for the industrial sector. Our high-precision capabilities allow us to produce near–net-shape gear blanks that require less machining than those built with other processes, cutting down your overall costs. In addition, we use CNC machining to produce the highest-quality finish, and we employ keyway cutting to provide you with ready-to-hob gear blanks that meet the unparalleled precision and repeatability your products need.

    Request a quote from Accurate Specialties or contact us for more information on chill casting bronze gear blanks.