Glossary
Acme Thread An Acme thread is a type of American screw thread with a 29-degree angle that’s a cross between a square and V-shaped thread. Acme threads are stronger and more durable than square threads and can withstand heavier loads. They’re also easier to manufacture and operate better in environments with dirt and debris.
AIS (American Iron & Steel Compliance) is a partnership between the U.S. Environmental Protection Agency, (EPA) and States that provide loans via the CWSRF, (Clean Water State Revolving Fund) and/or the DWSRF, (Drinking Water State Revolving Fund).
States receiving this assistance must use iron and steel products that are produced here in the United States. This requirement applies to projects for the construction, alteration, maintenance, or repair of a public water system or treatment works.
AISI is an acronym for American Iron and Steel Institute. AISI members make over 80% of the steel produced in North America. AISI sets standards for steel companies around the U.S. in a push to improve the industry.
All Thread An All thread is a metal rod that has been threaded for its entire length. All thread is used for general purpose threaded fastening systems. All thread can be Rods, (12” or longer in length) or Studs, (less than 12” in length).
Alloy Steel Alloy steel is steel that is alloyed (mixed) with a variety of elements to improve its mechanical properties. Common alloyants include manganese (the most common), nickel, chromium, molybdenum, vanadium, silicon, and boron. Improved properties in alloy steel (as compared to carbon steel) are strength, hardness, toughness, wear resistance, corrosion resistance, hardenability, and hot hardness.
Aluminum is a lightweight corrosion-resistant, non-magnetic, ductile material commonly used in a wide range of applications including soda cans, kitchen foil, aircraft fuselage, and automobile frames
Anchor Bolt An anchor bolt is used to attach objects or structures to concrete. Anchor bolts consist of a threaded end, to which nut and washer can be attached for the external load. Usually anchor bolts are bent at one end to form a “J” or “L” shape, however, they also can be straight. Anchor bolts are extensively used on all types of projects.
ASTM International, (formerly known as the American Society for Testing and Materials), is a global organization that develops and publishes voluntary consensus standards for a wide range of materials, products, systems, and services. The purpose of these standards is to improve performance and safety.
Black Oxide also known as gun bluing or blackening, is a chemical conversion coating that’s applied to ferrous metals, stainless steel, copper, zinc, and other materials. The coating is created by immersing the material in an alkaline salt solution heated to around 285°F, which causes a reaction between the iron in the metal and the hot oxide bath. This reaction produces magnetite (Fe3O4) on the surface of the material, leaving a black coating.
Brass is a corrosion resistant alloy made of copper and zinc. It has good electrical and thermal conductivity and is often used also used where a more pleasing aesthetic is required because of its’ gold-like appearance.
The Buy American Act (BAA) of 1933, requires federal agencies to prioritize the purchase of domestic products and materials for contracts over a certain amount. The threshold is currently $10,000, but can be raised during emergencies. The BAA applies to goods, such as articles, materials, and supplies, that are purchased for public use.
Chromate is a chemical coating that is applied during the Zinc plating process. Please see Zinc Electro Plating.
Coarse Threads A coarse thread is primarily defined by the thread pitch, (the distance between two adjacent threads) and are a group of products also known as UNC, (Unified National Coarse). Coarse threads are the most popular thread group produced by AATP.
Coupling Nut A Coupling Nuts, (also known as an Extension nut), is a longer than normal threaded nut used for joining two threads together. The outside of the Coupling Nut is usually hex, giving the ability to hold, tighten or loosen with a wrench.
Cut Thread A cut thread (also known as a machined thread) is created by removing material from a bar or blank to produce a thread profile. This process can be done using a single point tool, threaded dies, thread mills, or a tap to achieve the desired thread pitch. Please note that AATP do not manufacture products with a cut thread. Our manufacturing process uses a roll thread, (please see Roll Threading).
DFARS (Defense Acquisition Regulations System), outlines the US Government requirements for directly or indirectly supplying the Department of Defense. These requirements range from Audit and Assessment Control, Internal Process Control, Cybersecurity and Counterfeit electronic parts clauses to a more basic requirement that materials must originate from a specific list of countries. This list was originally based exclusively on NATO countries but has since been expanded to include additional countries.
Draw Straight and Cut is where the draw-straight-cut (DSC) machine takes green wire coils and draws the wire into a uniform diameter, then straightens it and finally cuts it to a desired length. The straight-cut (SC) machines are similar; however, they start with wire on hats that has already been drawn.
F1554 references material specification ASTM F1554. This material was developed by the American Society for Testing and Materials (ASTM) for use in construction related projects such as Freeway signs, Street Lights and Traffic signals and replaces the former ASTM A307 Grade C material specification. At AATP F1554 meets the material specification ASTM F1554 Grade 55 (S1), which is a weldable grade of material.
GR8HT™ GR8HT™ROD and GR8HT™STUD are the brand names given to AATP’s range of Hight Tensile Threaded Rods and Studs certified to ASTM A354 Grade BD.
Grade BD is a grade of High Strength steel from the ASTM A354 Standard. It is almost identical in chemical and mechanical content to SAE J429 Grade 8 and offers the same tensile and Yield strengths but is far more readily available.
Heat Treatment describes the process used to alter the physical properties of a material. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, in order to achieve a hardening or softening of material.
Hot Dip Galvanizing (HDG) also known as HDG is the process of dipping steel products into a vat containing molten zinc. This type of Zinc Plating is inherently simple which provides an advantage over other corrosion protection method, and it generally provides a much thicker coating. Please also see Mechanical Galvanizing.
Knurling is a manufacturing process whereby a pattern of straight, angled, or crossed lines is cut or rolled into the material.
Make and Hold Order A “Make and Hold” order is a customer purchase order for multiple deliveries of the same item with delivery flexibility “built in”. For example a customer uses 1,000 pieces a month and places an order for 6 months stock, (6,000 pieces). However, AATP gives the customer 12 months in which to consume them.
Master Product List (MPL) is the list of items (SKU’s) that we have decided to stock at AATP. Sales has predetermined sales prices (based on quantity) for each item. Operations has predetermined minimum and maximum stock levels for each item. The different AATP divisions have different Master Product Lists.
Medium Carbon Steel is based on the amount of carbon inside of the steel during manufacturing. The AISI classifies medium carbon steel as anything with 0.25% to 0.60% carbon content. Medium carbon steel has great strength and does not wear easily. Some types are:
- AISI-1038 = .35-.42% carbon
- AISI-1040 = .37-.44% carbon
- AISI-1045 = .42-.50% carbon
- AISI-1541 = .36-.44% carbon
Metric is the European measurement system that is based on the power of ten. Examples would be, Lengths & Distances = millimeters, centimeters, meters and kilometers, i.e. Ten millimeters = a Centimeter. Ten Centimeters = a Decimeter. Ten Decimeters = a Meter. Ten Meters = a Dekameter. There are ten Dekameters to 100 meters and 1,000 meters to a Kilometer.
Passivation is a chemical process that coats a material’s surface to make it more resistant to corrosion. The process removes free iron particles from the material and creates a thin, protective layer of oxide. This layer prevents further oxidation and corrosion and can also improve the material’s appearance.
Pallet shipping refers to the transportation of goods using pallets as a standardized unit of loading and handling. A pallet is a flat, portable platform typically made of wood.
Pitch Diameter is a fundamental measurement of a screw, threaded hole, or tap and represents the diameter of an imaginary cylinder that passes through the thread at approximately halfway between the major and minor diameters.
Plain/Oil Finish refers to steel threaded products that only have a bit of oil from the threading process. No cleaning and/or plating has been done to the product after threading.
REACH is a set of regulations that are part of the European Union’s (EU) Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation. The regulation aims to protect human health and the environment from chemicals by requiring manufacturers to ensure their products are safe and provide detailed information on the substances they contain. Please also see Restriction of Hazardous Substances, (RoHS).
Rockwell Hardness is a measurement of hardness just as feet and inches is a measurement of height. There are three commonly used scales of Rockwell hardness, A,B & C. or HRA, HRB & HRC. These designations are followed by a number, the higher the number the harder the material.
- HRA applies to the hardness testing of thin steels.
- HRB applies to the hard ness testing of Copper Alloys, soft Steels, Aluminum Alloys and malleable iron etc.
- HRC applies to the hardness testing of Steel, Hard cast irons, Titanium, deep case-hardened materials and all materials where the hardness is expected to exceed HRB100.
Roll Threading is a process by which steel is extruded to form the threaded portion of a fastener, instead of being removed as in cut threading. So instead of cutting away material to produce a thread, the base material is passed through a set of thread rolling dies, it is this action that displaces the parent material and forms the threads.
Rounds are pieces of unthreaded steel that have been straightened and cut to length.
Shear is the process of “chopping” off a piece of bar stock. We shear drawn bar stock as the final step of the DSC process. We also have shear machines that take WIP bar stock and chop to length prior to threading. The alternative is to saw rather than shear.
Silicone Bronze is a low-lead material that is mainly composed of copper, the rest of the material is silicone. Silicone bronze has very good corrosion resistant properties.
Single-End Rods and Studs have threads at one end and the balance of the rod unthreaded and can be produced as either a right hand or left-hand thread. All AATP single end products are Specials.
Specials (SP) are parts that AATP manufactures to a customer’s specifications and are generally unique to that customer. These parts are made to order and typically would include left hand threads, (standard threads are right hand threads), non-standard lengths, non-standard material and parts to a customer drawing.
Stainless Steel refers to a steel that contains chromium (12% +) and is much more resistant to corrosion, rust and stain than Low Carbon steels. There are several different types of stainless steel. AATP produces products from SS304 (the most common) which is also known as 18-8 and also SS316, sometimes referred to as marine grade Stainless.
The primary difference between 304 Stainless and 316 Stainless is that 316 Stainless contains 2% molybdenum making it more resistant to corrosion caused by chlorides, such as sea water and de-icing salts.
Stock Specials (SS) are AATP items that are specials; however, a customer has committed to purchase them from us on a regular basis. Therefore, we will keep in inventory an agreed upon quantity of the stock special. Stock specials are only available for sale to the designated customer.
Stud Master is a hand fed chamfering machine which creates the chamfer at the end of either threaded products or bar stock.
Studs are threaded rods that are less than 12 inches in length. (Threaded Rods that are 12 inches or longer in length are referred to as Rods). Studs can be “all thread” or threaded at one end, (Single end), or at both ends, (Double end).
Thread Classes describes the looseness or tightness of fit between external threads (rods) and internal threads (nuts.) For Unified, imperial (inches/ feet) items, there are three types of thread classes—1A, 2A, and 3A.
- 1A—the loosest fit of the three classes; most popular specification for AATP items.
- 2A—the middle tolerance specification. Wire size items and all stainless steel items are produced with a 2A fit. AATP can quote on a special basis other items with a 2A fit.
- 3A—the highest tolerance thread class (not produced at AATP.)
For metric items, there are three types of thread classes—2g, 4g, and 6g. The 6g is the most popular metric thread class and roughly equivalent to 2A.
Thread Pitch is the distance between the same point on two adjacent threads of a screw or nut. That distance corresponds to how far the fastener will “travel” when turned 360 degrees.
Threaded Rod are defined as straight rod that has been threaded and is 12 inches or longer in length. (Threaded Rods below 12 inches are referred to as Studs). AATP produces threaded rod up to 12 feet in length. Threaded rod can be all thread, double-end or single-end thread.
Thread Size Designations Unified/Imperial/Inch size threads are described by the diameter followed by the TPI, (Threads Per Inch). e.g. A 1/2” Unified Coarse thread is 1/2”-13 as there are 13 threads for every inch of length, whereas as 1/2” Unified Fine thread is 1/2”-20 as there are 20 threads for every inch of length.
Metric Thread sizes are described by the diameter in mm followed by the Thread Pitch, (the distance between the same point on two adjacent threads). e.g. A 4mm thread is M4 x 0.7. as there is 0.7mm between each thread.
Please Note: Metric threads as standard are coarse. A Fine metric thread is available but tends to be manufactured to order.
USS Flat Washer is a thin plate (typically disk-shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded as a screw or nut. Common materials include steel, stainless steel, and plastic.
Wire Size Threaded Rods & Studs are made from wire with a diameter that is less than 1/4”. Small wire is designated with a number (0 through 12, with 0 being the smallest and 12 the largest diameters). Wire size Threaded Rods & Studs use that number plus the threads per inch, (TPI) to designate the diameter and thread pitch, i.e. 2-56 or 12-24.
Yield Stress (WIP) also known as yield point, is a material property that measures the minimum amount of stress required to make a material deform plastically and flow. It’s the point at which a solid will transition from elastic to plastic behavior, and some of the deformation becomes permanent and irreversible. (See also Tensile Strength).
Zinc Electro Plating is where a thin Zinc coating is applied to finished products. Zinc’s excellent corrosion resistance in most environments’ accounts for its successful use as a protective coating in many exposure conditions. The plating process includes cleaning, rinsing and then bathing in a zinc solution where an electrical current is introduced, this helps to bond the zinc ions to the metal surface being plated.
Zinc Plating is often applied with a Clear or Yellow Chromate, this adds an additional level of corrosion resistance to the Zinc plating. If yellow chromate is applied the resulting finish will have a rainbow or iridescent appearance with dominant yellow tones.
We are a prime U.S. manufacturer of a wide range of quality threaded products with facilities in Denver, Colorado and Lancaster, Pennsylvania.
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