Grinderpedia is your source for all things horizontal grinders, recyclers, and hammer hogs. Get the low-down on industry terminology, colloquialisms, and learn the ins-and-outs of Peterson’s industry-leading machines. Grinderpedia is your source for What You Need to Know.
Peterson’s Animal Bedding Grate is designed with smaller, more precise openings, to filter a smoother finer chip, for customers who require the highest standards for their animals. The animal bedding grate is ideal for customers looking for low static, low dust, smooth bedding fibers for multiple applications in agriculture, animal care markets.
The best material to use for animal bedding is small, ground wood fiber that will not compact and allows adequate air flow.
A small opening grate, generally < 1” (2.54 cm), that has thinner webbing between the openings so that the grate will have more open area to increase productivity.
The anvil is a long steel bar with beveled cutting edges and plays an integral part in the Peterson 3-stage product sizing process. Located at the top and just to the rear in the grinding chamber, the anvil is contacted by the feedstock with the help of the grinding bit. This collision fractures the feed material into smaller fragments until they are small enough to pass out of the chamber via the grate system.
The Anvil Breaker Grate is a Peterson innovation which can be used for grinding asphalt shingles or waste wood for mulch. The breaker grate has chromium steel breaker bars welded to the inside face which helps break up material more efficiently preventing unwanted spears. The abrasion resistant steel bars helps to extend the service life of this grate.
The ASG Breaker Grate is a specific type of Peterson anvil breaker grate used specifically for asphalt shingle grinding. The breaker grate has chromium steel breaker bars welded to the inside face which helps break up material more efficiently with this abrasive grinding feedstock. The abrasion resistant steel bars helps to extend the service life of this grate. These have small holes to get the desired output.
Baffled grates have steel strips welded horizontally across the backside of the grate under the hole openings. These strips help hold long wood spears within the opening so a trailing grinding bit can break the long piece of wood into smaller fragments preventing these unwanted spears from ending up in the finished pile.
The Bear Claw Bit utilizes carbide insert technology to create an extremely aggressive grinding bit that is best used when grinding solid wood in a clean, contaminant free environment. The wear-resistant carbide inserts are brazed onto the forging and resemble the claws of a bear.
A bit spacer is the 1/4″ (6.35 mm) steel plate that is installed between the backside of a grinding bit and the frontside of a bit holder. This spacer is there to protect the expensive bit holder from damage should an operator fail to notice when a grinding bit needs to be changed out due to excessive wear.
An overlay is a process that bonds one or more metals to a base metal via welding. In the case of a grinding bit, the steel forging is the base metal and the overlay that is applied to the forging consists of abrasion resistant weld wire and carbide particles. During application, the weld wire and forging are heated creating a weld pool. Carbide particles of various grit sizes are introduced into this weld pool which metalurgically bonds to the steel forging. When the weld cools, the carbide is locked into place within and on the surface of the weld. The carbide overlay provides the wear resistant protection needed to prolong the service life of a grinding bit.
The Chain Curtain is positioned behind the grinding chamber, but above the debris belt. As some ground material can travel through the grates at a high velocity, the Chain Curtain is designed to slow down ground material to stop if from piercing the discharge belt.
A grate is a rectangular piece of steel that contains a pattern of holes which helps size feed material and allows it to pass from the grinding chamber to the discharge belt. After the holes are cut into the steel, the rectangle is bent in a radius along the horizontal axis. In a Peterson grinder, four grates are installed in the grinding chamber, one grate is installed on the anvil housing and the other three rest on grate supports.
The grate opening refers to the hole size and hole shape that is cut into a steel grate. The grate opening allows material to exit the grinding mill onto the discharge conveyor. Grate hole sizes can be as small as 5/8″ (1.5875 cm) and as large as 8″ (20.32 cm) and anywhere in between. The most common hole shapes are hex, round, square, diamond, and rectangle.
Grate position refers to the order in which the grates are installed in the grinding mill. On a Peterson machine, the first grate is attached to the anvil housing and is referred to as the #1 position. The #2 position is just below the anvil housing followed by the #3 and #4 positions. The three grates that follow the #1 position all rest on a set of grate supports in the grinding mill.
With four different grate positions, grates can be mixed and matched to create different combinations depending on feedstock and finished product. With so many variables to grinding (everything from moisture content, feedstock, and even season) there are no set rules and lots of experimentation. However, when using a grate combination, generally, smaller opening grates in the top two positions for sizing followed by progressively larger opening grates to use as exhaust grates. Hole shapes are generally the same but this too can vary based on preferences.
The hammer is the bit holder and bit assembly, which includes the bit spacer. The hammer strikes against the anvil, breaking material up.
The bit holder can be referred to as the hammer without referring to the whole assembly. A series of holders are welded to a shell rotor or secured in place by rotor pins to a pinned rotor in a predetermined pattern, each holding a grinding bit. Grinding bits are secured to the holders by bolts, washers, and lock nuts.
The Heavy-Duty 8-Pass Bit is a carbide overlaybit with 8 passes of carbide protection on the forging. All four cutting edges along with two passes on the side of the forging as well as two passes on the face of the forging on either side of the bolt holes make up the 8 passes of carbide on this grinder bit.
A hex grate refers to the hole shape that is cut into the face of a grate which allows end product to pass through. A hexagonal pattern is made up of 6 sides and 6 angles which allow 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. The hex grate pattern makes up over 75% of all Peterson grate sales.
The Peterson High Abrasion bit utilizes a cast carbide technology for maximum service life in the most extreme applications. The entire face of the bit is embedded with abrasion resistant carbide particles and the corners of the forging are reinforced with hardface wire creating a grinding bit that will hold up when standard carbide overlay bits will not.
A Knife Edge Bit is a heat-treated steel forging with sharply ground cutting edges much like the blade of a knife. The sharp edges “cut” wood rather than “hammer” wood creating a “clean” wood fragment rather than a “fuzzy” wood fragment produced by a carbide overlay bit. The edges of these bits can be resharpened using a diegrinder with a diamond flapper wheel.
A rectangular grate has rectangle shaped grate openings in the grate material. This style provides very good sizing but without the decrease in productivity experienced with round openings.
A rectangular grate refers to the hole shape that is cut into the face of a grate which allows end product to pass through. A rectangle pattern made up of 4 sides with the two horizontal sides being longer than the two vertical sides. This hole shape can reduce spearing and is generally used when grinding for a finished product.
A round grate refers to the hole shape that is cut into the face of a grate which allows end product to pass through. A round hole, generally limited to 2” (5.08 cm) or less opening size, produces a more consistent sized product and is used when grinding for a finished product. This style of grate provides the most consistent sizing when 1” (2.54 cm) minus or smaller product is required.
A Sharp Edge Bit is a carbide overlay bit with tall, sharp cutting edges. This bit cuts through dense, woody material efficiently and with less energy than a more blunt edge bit saving fuel and increasing production.
The Standard 6-Pass bit is a carbide overlay bit with 6 passes of carbide protection on the forging. All four cutting edges along with two passes on either side of the forging make up the 6 passes of carbide protection on this grinder bit.
The Tiger Tooth bit is a carbide overlay bit similar to the Sharp Edge Bit but with the cutting edge notched in the middle creating two tall carbide overlay “teeth” on either end of the forging. These “teeth” can efficiently penetrate and break apart solid wood.