Grate Selection Guide

Green waste can be used to create high-quality, deep, rich compost, or fuzzy, stringy materials for erosion control. The desired output in combination with bit or tip tooling will determine the best grate or screen selection. Hex grates with a smaller opening do the majority of the product sizing, while paired with larger opening hex grates for material reduction.

Leaf recycling, a speciality within green waste recycling, can be very abrasive to machine tooling due to sand and dirt contamination – using larger opening hex grates so feedstock doesn’t get clogged up.

Some processors who are working with wet, soggy, or clumpy materials may choose to use a diamond screen, which helps reduce clogging for these types of materials.

Most Common: hex or round with small to medium holes

Wood waste recycling can include pallets, sawmill residuals, or forestry slash. Each of these wood types have different grinding characteristics which will make an impact on your overall tooling selection.

Bark residuals from forestry applications is processed into value-added bark mulch and often processed with smaller hex grates or round grates for highly consistent finished products.

Pallet recyclers often use breaker grates which provide more contact in the grinding chamber as the additional bars on the grates act as mini anvils — creating less spearing, more fines, and a smaller material.

Most Common: hex or round or breaker grates

Land clearing of stumps and dense forestry material is most efficient when feedstock piles are reduced quickly. Using larger opening hex or square grates ensures the high production needed for this application.

Most Common: large opening hex or square

Construction and demolition and municipal solid waste materials, whether ground on location or at a waste facility, must be quickly reduced for efficient, economical transport or to maximize landfill space through compaction. Larger opening hex grates deliver the high production required for this application and help minimize catastrophic impacts by allowing material to pass through more easily. Some grinder operators may choose to use breaker grates for added durability when processing in this harsh environment.

Most Common: extra-large opening hex or square

Asphalt shingles are highly abrasive. The recommended grate for this application is a round breaker grate. The steel breaker bars on this grate act as additional anvils breaking up material and adding wear life to the grate, while the round holes provide a highly consistent output material.

Most Common: round breaker grate with small holes

Railroad ties are dense, creosote-treated hardwood with embedded metal contaminates. Using larger hole openings on a breaker-style grate such as square or rectangle can provide higher productivity while maintaining material flow. Consider a progressive grate configuration with holes going from larger to smaller for a balanced throughput.

Most Common: square breaker grate with large holes

Mulch created from wood and green waste reducing waste from landfills. Grate selection can vary depending on the size of the final product desired. Some operators prefer a two-pass grind for mulch, using a larger hex opening grate for an initial grind, and a smaller round grate for a second grind creating a uniform finished product.

Most Common: hex and round grates

Compost turns low-value wood, food, and green waste into a high-value product. Producers will have a preference for one-pass versus two-pass grinding, which will have an impact on the grate selection. Because hex grates are very efficient for high-volume producers, it’s a one of the most popular selections for compost applications. Round grates create a consistent finished product with sizing is critical.  

Most Common: hex and round grates

Biomass grate selection can vary depending on the size of the final product desired. Hex grates with a smaller opening to do the majority of the product sizing, paired with larger opening hex grates make for a recommended combination.

Most Common: hex grates

HEX allows for efficient nesting of multiple hex shapes to maximize a grates open area. This grate is more productive because it has more cutting edges and a larger percentage of open area allowing higher productivity. It is our most popular shape with it’s balance between productivity and consistency.

ROUND holes, generally limited to smaller opening sizes, produce a more consistently sized product and is used when grinding for a finished product. This style of grate provides the most consistent sizing when 1” or smaller product is required. Round holes are typically aligned in rows and can be combined with breaker bars for abrasive feedstock materials.

SQUARE & RECTANGLE holes can provide good sizing. It is generally used for finished products. Rectangle holes are typically aligned in rows and can be combined with breaker bars acting as additional anvils.

DIAMOND grates are primarily used for processing difficult to grind materials. Diamond screens do not allow material to accumulate easily, as the hole is designed to move material to the diamond point. This shape is often recommended by specific OEM manufacturers. For general grinding purposes, most Wear Parts Resource customers find the standard hex provides better productivity.