Hacksaw - wikipedia Hacksaw This article is about the tool. For other uses, see Hacksaw ( disambiguation ). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( December 2009 ) Typical full - size hacksaw frame, with 12 '' blade A hacksaw is a fine - toothed saw, originally and mainly made for cutting metal. The equivalent saw for cutting wood is usually called bow saw. Most hacksaws are hand saws with a C - shaped frame that holds a blade under tension. Such hacksaws have a handle, usually a pistol grip, with pins for attaching a narrow disposable blade. The frames may also be adjustable to accommodate blades of different sizes. A screw or other mechanism is used to put the thin blade under tension. On hacksaws, as with most frame saws, the blade can be mounted with the teeth facing toward or away from the handle, resulting in cutting action on either the push or pull stroke. In normal use, cutting vertically downwards with work held in a bench vice, hacksaw blades are set to be facing forwards. Contents 1 Design 1.1 History 1.2 Blades 2 Uses 3 Variants 4 See also 5 References Design History While saws for cutting metal had been in use for many years, significant improvements in longevity and efficiency were made in the 1880s by Max Flower - Nash. Clemson, a founder of Clemson Bros., Inc of Middletown, New York, United States,. Clemson conducted tests which involved changing the dimensions, shapes of teeth, styles of set, and variable heat treatments of blades. Clemson claimed enormous improvements to the cutting ability of blades and built a major industrial operation manufacturing hacksaw blades sold under the trade name Star Hack Saw. In 1898, Clemson was granted US Patent 601947, which details various improvements in the hacksaw. Blades Small hacksaw Standard hacksaw blade lengths are 10 to 12 in ( 250 to 300 mm ). Blades can be as small as 6 in ( 150 mm ). Powered hacksaws may use large blades in a range of sizes, or small machines may use the same hand blades. The pitch of the teeth can be from fourteen to thirty - two teeth per inch ( TPI ) for a hand blade, with as few as three TPI for a large power hacksaw blade. The blade chosen is based on the thickness of the material being cut, with a minimum of three teeth in the material. As hacksaw teeth are so small, they are set in a `` wave '' set. As for other saws they are set from side to side to provide a kerf or clearance when sawing, but the set of a hacksaw changes gradually from tooth to tooth in a smooth curve, rather than alternate teeth set left and right. Hacksaw blades are normally quite brittle, so care needs to be taken to prevent brittle fracture of the blade. Early blades were of carbon steel, now termed ' low alloy ' blades, and were relatively soft and flexible. They avoided breakage, but also wore out rapidly. Except where cost is a particular concern, this type is now obsolete. ' Low alloy ' blades are still the only type available for the Junior hacksaw, which limits the usefulness of this otherwise popular saw. For several decades now, hacksaw blades have used high speed steel for their teeth, giving greatly improved cutting and tooth life. These blades were first available in the ' All - hard ' form which cut accurately but were extremely brittle. This limited their practical use to benchwork on a workpiece that was firmly clamped in a vice. A softer form of high speed steel blade was also available, which wore well and resisted breakage, but was less stiff and so less accurate for precise sawing. Since the 1980s, bi-metal blades have been used to give the advantages of both forms, without risk of breakage. A strip of high speed steel along the tooth edge is electron beam welded to a softer spine. As the price of these has dropped to be comparable with the older blades, their use is now almost universal. The most common blade is the 12 inch or 300 mm length. Hacksaw blades have a hole at each end for mounting them in the saw frame and the 12 inch / 300 mm dimension refers to the center to center distance between these mounting holes. The kerf produced by the blades is somewhat wider than the blade thickness due to the set of the teeth. It commonly varies between 0.030 and 0.063 inches / 0.75 and 1.6 mm depending on the pitch and set of the teeth. Uses Hacksaws were originally and principally made for cutting metal, but can also cut various other materials, such as plastic and wood ; for example, plumbers and electricians often cut plastic pipe and plastic conduit with them. Variants A panel hacksaw A panel hacksaw has a frame made of a deep, thin sheet aligned behind the blade 's kerf, so that the saw could cut into panels of sheet metal without the length of cut being restricted by the frame. The frame follows the blade down the kerf into the panel. Junior hacksaws are a small version with a half - size blade. Like coping saws, the blade has pins that are held by notches in the frame. Although potentially a useful tool for a toolbox or in confined spaces, the quality of blades in the Junior size is restricted and they are only made in the simple low alloy steels, not HSS. This restricts their usefulness. An electric hacksaw A power hacksaw ( or electric hacksaw ) is a type of hacksaw that is powered either by its own electric motor or connected to a stationary engine. Most power hacksaws are stationary machines but some portable models do exist ; the latter ( with frames ) have been displaced to some extent by reciprocating saws such as the Sawzall, which accept blades with hacksaw teeth. Stationary models usually have a mechanism to lift up the saw blade on the return stroke and some have a coolant pump to prevent the saw blade from overheating. Power hacksaws are not as commonly used in the metalworking industries as they once were. Bandsaws and cold saws have mostly displaced them. While stationary electric hacksaws are not very common, they are still produced. Power hacksaws of the type powered by stationary engines and line shafts, like other line - shaft - powered machines, are now rare ; museums and antique - tool hobbyists still preserve a few of them. See also Coping saw Fretsaw Piercing saw References Wikimedia Commons has media related to Hacksaws. Jump up ^ Woodley, G. MacLaren ( 1955 ). `` The Clemson Story ''. The Historical Society of Middletown. Archived from the original on 18 May 2014. Retrieved 18 May 2014. Jump up ^ `` US Patent : 601,947 ''. Google Patents. April 5, 1898. Retrieved 18 May 2014. Jump up ^ Machinery 's Handbook, 14th Edition, by Erik Oberg & F.D. Jones, The Industrial Press, 1952, pages 1390 - 1391 Metalworking Tools Cutting machines Bandsaw Cold saw Laser Miter saw Plasma Water jet cutter Cutting tools Broach Burr Chisel Counterbore Countersink End mill File Hand scraper Milling cutter Nibbler Reamer Shears Tipped tool Tool bit Forming tools Brake Die English wheel Hydraulic press Machine press Punch press Screw press Stamping press Hand tools Clamp Combination square Drift pin Hacksaw Hammer Hand scraper Machinist square Needlegun scaler Piercing saw Pliers Punch Scriber Tap and die Tongs Vise Workbench Wrench Machine tooling Angle plate Chuck Collet Fixture Indexing head Jig Lathe center Machine taper Magnetic base Mandrel Rotary table Wiggler Measuring instruments Bore gauge Caliper Center gauge Dial indicator Engineer 's blue Engineer 's spirit level Feeler gauge Gauge Gauge block Go / no go gauge Height gauge Machinist square Marking blue Marking gauge Marking out Micrometer Optical comparator Radius gauge Ruler Sine bar Straightedge Surface plate Tape measure Thread pitch gauge Vernier scale Smithing tools Anvil Forge Fuller Hardy tools Pritchel Steam hammer Swage block Trip hammer Casting Fabrication Forming Jewellery Machining Metallurgy Smithing Tools and terminology Welding Machine and metalworking tools arbor press automatic lathe ball - peen hammer broaching machine drill press end mill English wheel gear shaper grinding machine hacksaw hobbing machine jig borer lathe machine tool metal lathe milling cutter milling machine planer plasma cutter rotary transfer machine shaper tap and die thread restorer tool bit turret lathe welder Types of tools Cleaning Cutting and abrasive Forestry Garden Hand Machine and metalworking Measuring and alignment Power Retrieved from `` https://en.wikipedia.org/w/index.php?title=Hacksaw&oldid=862227845 '' Categories : Cutting machines Hand tools Saws Metalworking cutting tools Metalworking hand tools Hidden categories : CS1 : Julian -- Gregorian uncertainty Articles needing additional references from December 2009 All articles needing additional references Talk Variants Contents About Wikipedia Tools Беларуская བོད ་ ཡིག Català Deutsch Español Français Gaeilge 한국어 Nederlands Norsk Norsk nynorsk Polski Português Русский Simple English Svenska Українська 8 more Edit links This page was last edited on 3 October 2018, at 00 : 26 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what determines the number of teeth to use on a hacksaw
Answer: based on the thickness of the material being cut