Cold saw

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Portable cold saw with the chip catcher detached Makita-cold-saw-catcher.JPG
Portable cold saw with the chip catcher detached

A cold saw is a circular saw designed to cut metal which uses a toothed blade to transfer the heat generated by cutting to the chips created by the saw blade, allowing both the blade and material being cut to remain cool. [1] This is in contrast to an abrasive saw, which abrades the metal and generates a great deal of heat absorbed by the material being cut and saw blade. [2]

Contents

As metals expand when heated, abrasive cutting causes both the material being cut and blade to expand, resulting in increased effort to produce a cut and potential binding. This produces more heat through friction, resulting in increased blade wear and greater energy consumption.

Cold saws use either a solid high-speed steel (HSS) [3] or tungsten carbide-tipped, resharpenable circular saw blade. [4] They are equipped with an electric motor and often a gear reduction unit [5] to reduce the saw blade's rotational speed while maintaining constant torque. This allows the HSS saw blade to feed at a constant rate with a very high chip load per tooth.

Cold saws are capable of machining most ferrous and non-ferrous alloys. Additional advantages include minimal burr production, fewer sparks, less discoloration and no dust. Saws designed to employ a flood coolant system to keep saw blade teeth cooled and lubricated may reduce sparks and discoloration completely. Saw blade type and number of teeth, cutting speed, and feed rate all must be appropriate to the type and size of material being cut, which must be mechanically clamped to prevent movement during the cutting process.

Blades

Cold saw blades are circular metal cutting saw blades categorized into two types: solid HSS or tungsten carbide-tipped (TCT). Both types of blades are resharpenable and may be used many times before being discarded. Cold saw blades are used to cut metal using a relatively slow rotational speed, usually less than 5000 surface feet per minute (SFM) (25 m/s), and a high chip load per tooth, usually between .001"–.003" (0.025–0.08 mm) per tooth. These blades are driven by a high power motor and high-torque gear reduction unit or an AC vector drive. During the cutting process, the metal is released in a shearing action by the teeth as the blade turns and the feed mechanism moves the blade forward. They are called "cold saw blades" because they transfer all the energy and heat created during the cutting process to the chip. This enables the blade and the work material to remain cold.

Classification

The first type of cold saw blade, solid HSS, may be made from either M2 tool steel or M35 tool steel, alloyed with additional cobalt. Solid HSS saw blades are heat treated and hardened to 64/65 HRC for ferrous cutting applications and 58/60 HRC for non-ferrous cutting applications. This high hardness gives the cutting edges of the teeth a high resistance to heat and wear. However, this increased hardness also makes the blades brittle and not very resistant to shock. In order to produce a high quality HSS cold saw blade, it is necessary to start with very flat and properly tensioned raw material. The blades must be press quenched after hardening to prevent them from being warped. HSS saw blades are typically hollow ground for clearance during the cutting process. The term HSS doesn't necessarily mean what it implies. These blades are usually never run at surface speeds higher than 350 SFM. Solid HSS cold saw blades may be used for cutting many different shapes and types of metal including: tubes, extrusions, structural sections, billets, bars, ingots, castings, forgings etc. These blades may also be coated with special wear resistant coatings such as titanium nitride (TiN) or titanium aluminum nitride (TiAlN), but are more commonly used commercially with a black oxide coating aiding in better coolant distribution over the surface area of the cutting blade.

The second type of cold saw blade, tungsten carbide-tipped (TCT), are made with an alloy steel body and tungsten carbide inserts brazed to the tips of the teeth. These tips are ground on all surfaces to create tangential and radial clearance and provide the proper cutting and clearance angles on the teeth. The alloy body is generally made from a wear-resistant material such as a chrome vanadium steel, heat treated to 38/42 HRC. The tungsten carbide tips are capable of operating at much higher temperatures than solid HSS, therefore, TCT saw blades are usually run at much higher surface speeds. This allows carbide-tipped blades to cut at faster rates and still maintain an acceptable chip load per tooth. These blades are commonly used for cutting non-ferrous alloys, but have gained significant popularity for ferrous metal cutting applications in the last 10 years. The tungsten carbide inserts are extremely hard (98 HRC) and capable of very long wear life. However, they are less resistant to shock than solid HSS cold saw blades. Any vibration during the cutting process may severely damage the teeth. These cold saw blades need to be driven by a backlash free gear box and a constant feed mechanism like a ball-screw feed.

Portable saws

Portable cold saws were primarily designed for sheet metal roofers in the building industry,[ citation needed ] and can cut up to 6 mm (0.24 in) thick mild steel. Cold saws, as opposed to abrasive saws, are used so that protective coatings are not damaged. They have a heavy duty aluminium catcher which is useful for capturing the swarf, and use cermet tipped blades.

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<span class="mw-page-title-main">Circular saw</span> Power tool

A circular saw is a power-saw using a toothed or abrasive disc or blade to cut different materials using a rotary motion spinning around an arbor. A hole saw and ring saw also use a rotary motion but are different from a circular saw. Circular saws may also be loosely used for the blade itself. Circular saws were invented in the late 18th century and were in common use in sawmills in the United States by the middle of the 19th century.

A saw is a tool consisting of a tough blade, wire, or chain with a hard toothed edge. It is used to cut through material, very often wood, though sometimes metal or stone. The cut is made by placing the toothed edge against the material and moving it back and forth, or continuously forward. This force may be applied by hand, or powered by steam, water, electricity or other power source. An abrasive saw has a powered circular blade designed to cut through metal or ceramic.

<span class="mw-page-title-main">Drill bit</span> Type of cutting tool

Drill bits are cutting tools used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. In order to create holes drill bits are usually attached to a drill, which powers them to cut through the workpiece, typically by rotation. The drill will grasp the upper end of a bit called the shank in the chuck.

<span class="mw-page-title-main">Tool steel</span> Any of various steels that are particularly well-suited to be made into tools and tooling

Tool steel is any of various carbon steels and alloy steels that are particularly well-suited to be made into tools and tooling, including cutting tools, dies, hand tools, knives, and others. Their suitability comes from their distinctive hardness, resistance to abrasion and deformation, and their ability to hold a cutting edge at elevated temperatures. As a result, tool steels are suited for use in the shaping of other materials, as for example in cutting, machining, stamping, or forging.

<span class="mw-page-title-main">High-speed steel</span> Subset of tool steels

High-speed steel is a subset of tool steels, commonly used as cutting tool material.

<span class="mw-page-title-main">Tungsten carbide</span> Hard, dense and stiff chemical compound

Tungsten carbide is a chemical compound containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells and jewelry.

<span class="mw-page-title-main">Bandsaw</span> Power saw with a long, sharp blade

A bandsaw is a power saw with a long, sharp blade consisting of a continuous band of toothed metal stretched between two or more wheels to cut material. They are used principally in woodworking, metalworking, and lumbering, but may cut a variety of materials. Advantages include uniform cutting action as a result of an evenly distributed tooth load, and the ability to cut irregular or curved shapes like a jigsaw. The minimum radius of a curve is determined by the width of the band and its kerf. Most bandsaws have two wheels rotating in the same plane, one of which is powered, although some may have three or four to distribute the load. The blade itself can come in a variety of sizes and tooth pitches, which enables the machine to be highly versatile and able to cut a wide variety of materials including wood, metal and plastic.

Broaching is a machining process that uses a toothed tool, called a broach, to remove material. There are two main types of broaching: linear and rotary. In linear broaching, which is the more common process, the broach is run linearly against a surface of the workpiece to produce the cut. Linear broaches are used in a broaching machine, which is also sometimes shortened to broach. In rotary broaching, the broach is rotated and pressed into the workpiece to cut an axisymmetric shape. A rotary broach is used in a lathe or screw machine. In both processes the cut is performed in one pass of the broach, which makes it very efficient.

A hacksaw is a fine-toothed saw, originally and mainly made for cutting metal. The equivalent saw for cutting wood is usually called a bow saw.

<span class="mw-page-title-main">Titanium carbide</span> Chemical compound

Titanium carbide, TiC, is an extremely hard refractory ceramic material, similar to tungsten carbide. It has the appearance of black powder with the sodium chloride crystal structure.

<span class="mw-page-title-main">Tool bit</span> Non-rotary cutting tool used in machining

In machining, a tool bit is a non-rotary cutting tool used in metal lathes, shapers, and planers. Such cutters are also often referred to by the set-phrase name of single-point cutting tool, as distinguished from other cutting tools such as a saw or water jet cutter. The cutting edge is ground to suit a particular machining operation and may be resharpened or reshaped as needed. The ground tool bit is held rigidly by a tool holder while it is cutting.

Milling cutters are cutting tools typically used in milling machines or machining centres to perform milling operations. They remove material by their movement within the machine or directly from the cutter's shape.

<span class="mw-page-title-main">Tipped tool</span> Cutting tool whose cutting edge is a separate piece of material

A tipped tool is any cutting tool in which the cutting edge consists of a separate piece of material that is brazed, welded, or clamped onto a body made of another material. In the types in which the cutter portion is an indexable part clamped by a screw, the cutters are called inserts. Tipped tools allow each part of the tool, the shank and the cutter(s), to be made of the material with the best properties for its job. Common materials for the cutters include cemented carbide, polycrystalline diamond, and cubic boron nitride. Tools that are commonly tipped include milling cutters, tool bits, router bits, and saw blades.

<span class="mw-page-title-main">Diamond tool</span>

A diamond tool is a cutting tool with diamond grains fixed on the functional parts of the tool via a bonding material or another method. As diamond is a superhard material, diamond tools have many advantages as compared with tools made with common abrasives such as corundum and silicon carbide.

<span class="mw-page-title-main">Cemented carbide</span> Type of composite material

Cemented carbides are a class of hard materials used extensively for cutting tools, as well as in other industrial applications. It consists of fine particles of carbide cemented into a composite by a binder metal. Cemented carbides commonly use tungsten carbide (WC), titanium carbide (TiC), or tantalum carbide (TaC) as the aggregate. Mentions of "carbide" or "tungsten carbide" in industrial contexts usually refer to these cemented composites.

The saw chain, or cutting chain, is a key component of a chainsaw. It consists of steel links held together by rivets, and superficially resembles the bicycle-style roller chain, although it is closer in design to a leaf chain. Its key differences are sharp cutting teeth on the outside of the chain loop, and flat drive links on the inside, to retain the chain on the saw's bar and allow propulsion by the engine or motor.

Carbide saws are machine tools for cutting. The saw teeth are made of cemented carbide, so that hard materials can be cut.

<span class="mw-page-title-main">Annular cutter</span>

An annular cutter is a form of core drill used to create holes in metal. An annular cutter, named after the annulus shape, cuts only a groove at the periphery of the hole and leaves a solid core or slug at the center.

<span class="mw-page-title-main">Jigsaw (tool)</span> Type of saw

A jigsaw is a saw which uses a reciprocating blade to cut irregular curves, such as stenciled designs, in wood, metal, or other materials.

References

  1. Dunn, Michael (2019-11-28). "The 11 Best Cold Cut Metal Saws [2023 Review]" . Retrieved 2023-07-02.
  2. "Do A Lot of Cutting Through Steel? Get One of These Best Chop Saws". Popular Mechanics. 2022-07-12. Retrieved 2023-07-02.
  3. "M2 HSS Cold Saw Blades - Cold Saw Blade Store" . Retrieved 2023-07-02.
  4. "Heinemann Saw". www.heinemannsaw.com. Retrieved 2023-07-02.
  5. Digest, Team Tool (2020-06-04). "Best Cold Saws 2022: For a Smooth Finish - Tool Digest" . Retrieved 2023-07-02.