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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.

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68-515: [REDACTED] Look up broach in Wiktionary, the free dictionary. Broach may refer to: Broaching (metalworking) , a machining operation that uses a metalworking tool with a series of chisel points mounted on one piece of steel Broach (nautical) , a sudden loss of control of a vessel caused either by wind action or wave action BROACH warhead , an advanced multi-stage warhead developed by

136-1169: A grindstone . The exact details of the heat treatment and tip geometry were a matter of individual experience and preference. A substantial technological advance occurred in the 1890–1910 period, when Frederick Winslow Taylor applied scientific methods to the study of tool bits and their cutting performance (including their geometry, metallurgy, and heat treatment, and the resulting speeds and feeds , depths of cut, metal-removal rates, and tool life). Along with Maunsel White and various assistants, he developed high-speed steels (whose properties come from both their alloying element mixtures and their heat treatment methods). His cutting experiments chewed through tons of workpiece material, consumed thousands of tool bits, and generated mountains of chips. They were sponsored in large part by William Sellers (a principal of Midvale Steel and Cramp's shipyard) and later by Bethlehem Steel . Not only did Taylor develop new materials to make single-point cutters from, but he also determined optimum geometry (rake angles, clearance angles, nose radiuses, etc.). He developed Taylor's Equation for Tool Life Expectancy . After Taylor, it

204-438: A "balanced turning tool"), in which case the box tool begins to overlap in form, function, and identity with a hollow mill . Shapers , slotters, and planers often employ a kind of toolholder called a clapper box that swings freely on the return stroke of the ram or bed. On the next cutting stroke, it "claps" back into cutting position. Its movement is analogous to that of a butterfly-style check valve . Fly cutters are

272-442: A blind hole, while a rotary broach can, as long as there is sufficient space for chips at the bottom of the hole. Tool bit 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

340-426: A broach is called a rotary broach or wobble broach . One of the biggest advantages to this type of broaching is that it does not require a broaching machine, but instead is used on lathes, milling machines, screw machines or Swiss lathes . Rotary broaching requires two tooling components: a tool holder and a broach. The leading (cutting) edge of the broach has a contour matching the desired final shape. The broach

408-420: A broach that is longer than if a standard design were used. For some circular broaches, burnishing teeth are provided instead of finishing teeth. They are not really teeth, as they are just rounded discs that are 0.001 to 0.003 in (0.025 to 0.076 mm) oversized. This results in burnishing the hole to the proper size. This is primarily used on non-ferrous and cast iron workpieces. The pitch defines

476-599: A city and district in south Gujarat state in India Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Broach . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Broach&oldid=960598747 " Categories : Disambiguation pages Disambiguation pages with surname-holder lists Hidden categories: Short description

544-489: A consortium of British companies Broach spire , a spire that starts on a square base and is carried up to a tapering octagonal spire by means of triangular faces Barbed broach , a dental instrument People [ edit ] Chris Broach (born 1976), American musician in the band Braid Elise Broach (born 1963), American author See also [ edit ] Brooch , a decorative item designed to be attached to garments Bharuch , also known as "Broach",

612-461: A flat surface. The first is similar to the rotor-cut design, which is known as a double-cut design. Here four teeth in a row have the same RPT, but each progressive tooth takes only a portion of the cut due to notches in the teeth (see the image gallery below). The other option is known as a progressive broach, which completely machines the center of the workpiece and then the rest of the broach machines outward from there. All of these designs require

680-412: A greater risk of the part breaking off. When turning longer lengths, a support from the turret can be used to increase turning length from 2.5 times to 5 times the smallest diameter of the part being turned, and this also can help reduce chatter. Despite the drawbacks, the elimination of extra operations often makes using form tools the most efficient option. By confining the expensive hard cutting tip to

748-503: A guided ram; typical capacities are 5 to 50 tons. The two ram pull-down machine is the most common type of broaching machine. This style machine has the rams under the table. Pull-up machines have the ram above the table; they usually have more than one ram. Most surface broaching is done on a vertical machine. Horizontal broaching machines are designed for pull broaching, surface broaching, continuous broaching, and rotary broaching. Pull style machines are basically vertical machines laid on

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816-552: A long time, it was not until these new, expensive metals came about that the idea of cutting inserts became commonly applied in machining. Before this, most single-point cutters were forged entirely of tool steel (then ground at the tip). Now it became more common to attach a separate tip (of one material) to a holder (of another). With the development of commercially available cemented carbide (1920s) and ceramic inserts (post-WWII), this trend accelerated, because carbide and ceramic are even more expensive and even less suited to serving as

884-454: A shank. The technological development, however, did not immediately displace the older ways. Between 1900 and 1950, it was still not uncommon for a machinist to forge a tool from carbon tool steel. Today, among the single-point cutters used in mass production (such as of automotive parts), insert tools using carbide and ceramic far outnumber HSS or cobalt steel tools. In other machining contexts (e.g., job shops, toolrooms, and hobbyist practice),

952-403: A special holding fixture , called a workholder , which mounts in the broaching machine. The broaching machine elevator , which is the part of the machine that moves the broach above the workholder, then lowers the broach through the workpiece. Once through, the broaching machine's puller , essentially a hook, grabs the pilot of the broach. The elevator then releases the top of the follower and

1020-572: A type of milling cutter in which one or two tool bits are mounted. The bits spin around with the rotation of the spindle, taking facing cuts. Fly cutters are an application of tool bits where the bits are part of a rotary unit (whereas most other tool bit use is linear). Tool bits have been used for centuries, yet their further technological development continues even today. Before about 1900, almost all tool bits were made by their users, and many machine shops had forges . In fact, good machinists were expected to have blacksmithing knowledge, and although

1088-422: A workpiece in one pass. This type of broaching holds closer tolerances than if the two cuts were done independently. It is named after the fact that the broaches "straddle" the workpiece on multiple sides. Solid broaches are the most common type; they are made from one solid piece of material. For broaches that wear out quickly shell broaches are used; these broaches are similar to a solid broach, except there

1156-427: Is a hole through the center where it mounts on an arbor . Shell broaches cost more initially, but save the cost overall if the broach must be replaced often because the pilots are on the mandrel and do not have to be reproduced with each replacement. Modular broaches are commonly used for large internal broaching applications. They are similar to shell broaches in that they are a multi-piece construction. This design

1224-500: Is between 16 and 24 Rockwell C (HRC); a hardness greater than HRC 35 will dull the broach quickly. Broaching is more difficult on harder materials, stainless steel and titanium , but is still possible. Broaches can be categorized by many means: If the broach is large enough the costs can be reduced by using a built-up or modular construction. This involves producing the broach in pieces and assembling it. If any portion wears out only that section has to be replaced, instead of

1292-489: Is different from Wikidata All article disambiguation pages All disambiguation pages Broaching (metalworking) Broaching is used when precision machining is required, especially for odd shapes. Commonly machined surfaces include circular and non-circular holes, splines , keyways , and flat surfaces. Typical workpieces include small to medium-sized castings , forgings , screw machine parts, and stampings . Even though broaches can be expensive, broaching

1360-426: Is effectively a collection of single-point cutting tools arrayed in sequence, cutting one after the other; its cut is analogous to multiple passes of a shaper . The concept of broaching can be traced back to the early 1850s, with the first applications used for cutting keyways in pulleys and gears . After World War I , broaching was used to rifle gun barrels. In the 1920s and 30s the tolerances were tightened and

1428-402: 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. Back rake is to help control the direction of the chip, which naturally curves into the work due to the difference in length from the outer and inner parts of the cut. It also helps counteract the pressure against the tool from

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1496-405: Is mounted in a special tool holder that allows it to freely rotate. The tool holder is special because it holds the tool so that its axis of rotation is inclined slightly to the axis of rotation of the work. A typical value for this misalignment is 1°. This angle is what produces a rotating edge for the broach to cut the workpiece. Either the workpiece or the tool holder is rotated. If the tool holder

1564-407: Is mounted on the turret of a turret lathe or screw machine . It is essentially a toolpost that brings its follower rest along with it. A tool bit (or several tool bits) and a compact follower rest (usually V-shaped or with two rollers ) are mounted opposite each other in a body which surrounds the workpiece (forms a "box" around it). As the tool bit puts a lateral deflecting force on the workpiece,

1632-424: Is much quicker than milling when more than one slot needs to be machined, because multiple broaches can be run through the part at the same time on the same broaching machine. Contour broaches are designed to cut concave, convex, cam, contoured, and irregular shaped surfaces. Pot broaches are cut the inverse of an internal broach; they cut the outside diameter of a cylindrical workpiece. They are named after

1700-407: Is often impossible without the specific broaching or keyway machines unless you have a system that can be used in conjunction with a modern machining centre or driven tooling lathe; these extra bits of equipment open up the possibility of producing keyways, splines and Torx through one-hit machining. A somewhat different design of cutting tool that can achieve the irregular hole or outer profile of

1768-521: Is possible to achieve a range of 0.05 to 13 in (1.3 to 330.2 mm). Surface broaches' range is usually 0.075 to 10 in (1.9 to 254.0 mm), although the feasible range is 0.02 to 20 in (0.51 to 508.00 mm). Tolerances are usually ±0.002 in (±0.05 mm), but in precise applications a tolerance of ±0.0005 in (±0.01 mm) can be held. Surface finishes are usually between 16 and 63 microinches (μin), but can range from 8 to 125 μin. There may be small burrs on

1836-443: Is precision-ground into a pattern that resembles the part to be formed. The form tool can be used as a single operation and therefore eliminate many other operations from the slides (front, rear and/or vertical) and the turret, such as box tools . A form tool turns one or more diameters while feeding into the work. Before the use of form tools, diameters were turned by multiple slide and turret operations, and thus took more work to make

1904-410: Is rotated, the misalignment causes the broach to appear as though it is "wobbling", which is the origin of the term wobble broach . For internal broaching the sides of the broach are drafted inward so it becomes thinner; for external broaching the sides are drafted outward, to make the pocket bigger. This draft keeps the broach from jamming; the draft must be larger than the angle of misalignment. If

1972-432: Is to reverse the rotation in mid cut, causing the tool to spiral in the opposite direction. If reversing the machine is not practical, then interrupting the cut is another possible solution. In general, a rotary broach will not cut as accurately as a push or pull broach. However, the ability to use this type of cutting tool on common machine tools is highly advantageous. In addition, push or pull broaches cannot be used in

2040-400: Is used because it is cheaper to build and resharpen and is more flexible than a solid design. A common type of internal broach is the keyway broach (C & D). It uses a special fixture called a horn to support the broach and properly locate the part with relation to the broach. A concentricity broach is a special type of spline cutting broach which cuts both the minor diameter and

2108-408: Is usually favored over other processes when used for high-quantity production runs. Broaches are shaped similar to a saw, except the height of the teeth increases over the length of the tool. Moreover, the broach contains three distinct sections: one for roughing, another for semi-finishing, and the final one for finishing. Broaching is an unusual machining process because it has the feed built into

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2176-438: Is usually only viable with high volume workpieces, because the broach can cost US$ 15,000 to US$ 30,000 to produce. Broaching speeds vary from 20 to 120  surface feet per minute (SFPM). This results in a complete cycle time of 5 to 30 seconds. Most of the time is consumed by the return stroke, broach handling, and workpiece loading and unloading. The only limitations on broaching are that there are no obstructions over

2244-553: Is usually the design driver of a tool holder, the steel used does not need to be particularly hard or strong as there is relatively little difference between the stiffnesses of most steel alloys. The toolpost is the part of a metalworking lathe which either holds the tool bit directly or holds a toolholder which contains the tool bit. There are a great variety of designs for toolposts (including basic toolposts, rocker toolposts, quick-change toolposts, and toolpost turrets) and toolholders (with varying geometry and features). A box tool

2312-400: Is very brittle and will chip if chatter occurs. A drawback when using form tools is that the feed into the work is usually slow, 0.0005" to 0.0012" per revolution depending on the width of the tool. Wide form tools create more heat and usually are problematic for chatter. Heat and chatter reduces tool life. Also, form tools wider than 2.5 times the smaller diameter of the part being turned have

2380-491: The 20th century), sintered carbide (1930s), ceramic and diamond cutters, those materials have gradually replaced the earlier kinds of tool steel in almost all cutting applications. Most tool bits today are made of HSS, cobalt steel , or carbide. Carbide , ceramics (such as cubic boron nitride ) and diamond, having higher hardness than HSS, all allow faster material removal than HSS in most cases. Because these materials are more expensive and brittler than steel, typically

2448-456: The RPT is designated to two or three rows of teeth. For the broach to work the first tooth of that cluster has a wide notch, or undercut, and then the next tooth has a smaller notch (in a three tooth design) and the final tooth has no notch. This allows for a deep cut while keeping stresses, forces, and power requirements low. There are two different options for achieving the same goal when broaching

2516-399: The RPT is usually between 0.003 to 0.006 in (0.076 to 0.152 mm) and for diameter broaching is usually between 0.0012 to 0.0025 in (0.030 to 0.064 mm). The exact value depends on many factors. If the cut is too big it will impart too much stress into the teeth and the workpiece; if the cut is too small the teeth rub instead of cutting. One way to increase the RPT while keeping

2584-404: The body of the cutting tool is made of steel, and a small cutting edge made of the harder material is attached. The cutting edge is usually either screwed or clamped on (in this case it is called an insert), or brazed on to a steel shank (this is usually only done for carbide). Almost all high-performance cutting tools use indexable inserts . There are several reasons for this. First of all, at

2652-624: The broach in a linear motion at a predetermined speed and provide a means for handling the broach automatically. Most machines are hydraulic , but a few specialty machines are mechanically driven. The machines are distinguished by whether their motion is horizontal or vertical. The choice of machine is primarily dictated by the stroke required. Vertical broaching machines rarely have a stroke longer than 60 in (1.5 m). Vertical broaching machines can be designed for push broaching, pull-down broaching, pull-up broaching, or surface broaching. Push broaching machines are similar to an arbor press with

2720-525: The bulk of the material to reduce wear on the form tool. There are different types of form tools. Insert form tools are the most common for short- to medium-range jobs (50 to 20,000 pcs). Circular form tools are usually for longer jobs, since the tool wear can be ground off the tool tip many times as the tool is rotated in its holder. There is also a skiving tool that can be used for light finishing cuts. Form tools can be made of cobalt steel, carbide, or high-speed steel. Carbide requires additional care because it

2788-430: The chemistry and physics of the heat treatment of steel were not well understood (as compared with today's sciences), the practical art of heat treatment was quite advanced, and something that most skilled metalworkers were comfortably acquainted with. Tool bits were made of carbon tool steels , which have high enough carbon content to take hardening well. Each bit was forged with a hammer, quenched, and then ground with

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2856-409: The cost reduced thanks to advances in form grinding and broaching machines. The process depends on the type of broaching being performed. Surface broaching is very simple as either the workpiece is moved against a stationary surface broach, or the workpiece is held stationary while the broach is moved against it. Internal broaching is more involved. The process begins by clamping the workpiece into

2924-409: The edge and the reduced ability to absorb heat generated by cutting. The rake angles on the top of the tool need not be precise in order to cut but to cut efficiently there will be an optimum angle for back and side rake. Originally, all tool bits were made of high carbon tool steels with the appropriate hardening and tempering . Since the introductions of high-speed steel (HSS) (early years of

2992-533: The entire broach. Most broaches are made from high speed steel (HSS) or an alloy steel ; titanium nitride (TiN) coatings are common on HSS to prolong life. Except when broaching cast iron , tungsten carbide is rarely used as a tooth material because the cutting edge will crack on the first pass. The slab broach is the simplest surface broach. It is a general purpose tool for cutting flat surfaces. Slot broaches (G & H) are for cutting slots of various dimensions at high production rates. Slot broaching

3060-421: The exit side of the cut. Broaching works best on softer materials, such as brass , bronze , copper alloys , aluminium , graphite , hard rubbers , wood , composites , and plastic . However, it still has a good machinability rating on mild steels and free machining steels . When broaching, the machinability rating is closely related to the hardness of the material. For steels the ideal hardness range

3128-401: The finish of the cut smoother as it can overlap the previous cut and eliminate the peaks and valleys that a pointed tool produces. Having a radius also strengthens the tip, a sharp point being quite fragile. Nose radius varies depending on the machining operations like roughing, semi-finishing or finishing and also on the component material being cut: steel, cast iron, aluminium and others. All

3196-402: The follower rest opposes it, providing rigidity. A different and popular type of box tool uses two rollers rather than a follower rest. One roller is called a "sizing roller" and the other roller is called a "burnishing roller". The rollers turn with the stock to reduce scarring on the finished turn. Opposing tool bits may be used (instead of a rest) to cancel each other's deflecting forces (called

3264-480: The geometry of a broach an internal type is shown below. Note that the geometries of other broaches are similar. [REDACTED] [REDACTED] where: The most important characteristic of a broach is the rise per tooth (RPT), which is how much material is removed by each tooth. The RPT varies for each section of the broach, which are the roughing section ( t r ), semi-finishing section ( t s ), and finishing section ( t f ). The roughing teeth remove most of

3332-504: The latter are still well represented. An entire system of industry-standard notation has been developed to name each insert geometry type. The number of carbide and ceramic formulations continues to expand, and diamond is used more than ever before. Speeds, feeds, depths of cut, and temperatures at the cutting interface continue to rise (the latter counterbalanced by copious cooling via liquid, air, or aerosols ), and cycle times continue to shrink. Competition among product manufacturers to lower

3400-435: The length of the surface to be machined, the geometry to be cut does not have curves in multiple planes, and that the workpiece is strong enough to withstand the forces involved. Specifically for internal broaching a hole must first exist in the workpiece so the broach can enter. Also, there are limits on the size of internal cuts. Common internal holes can range from 0.125 to 6 in (3.2 to 152.4 mm) in diameter but it

3468-468: The material being cut. For steel, it is between 15 and 20° and for cast iron it is between 6 and 8°. The back-off ( γ ) provides clearance for the teeth so that they don't rub on the workpiece; it is usually between 1 and 3°. When radially broaching workpieces that require a deep cut per tooth, such as forgings or castings , a rotor-cut or jump-cut design can be used; these broaches are also known as free egress or nibbling broaches. In this design

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3536-447: The material so the number of roughing teeth required dictates how long the broach is. The semi-finishing teeth provide surface finish and the finishing teeth provide the final finishing. The finishing section's RPT (t f ) is usually zero so that as the first finishing teeth wear the later ones continue the sizing function. For free-machining steels the RPT ranges from 0.006 to 0.001 in (0.152 to 0.025 mm). For surface broaching

3604-410: The other angles are for clearance in order that no part of the tool besides the actual cutting edge can touch the work. The front clearance angle is usually 8 degrees while the side clearance angle is 10-15 degrees and partly depends on the rate of feed expected. Minimum angles which do the job required are advisable because the tool gets weaker as the edge gets keener due to the lessening support behind

3672-413: The part doing the actual cutting, the cost of tooling is reduced. The supporting tool holder can then be made from a tougher steel, which besides being cheaper is also usually better suited to the task, being less brittle than the cutting-edge materials. The tool holders may also be designed to introduce additional properties to the cutting action, such as: Note that since stiffness (rather than strength)

3740-400: The part. For example, a form tool can turn many diameters and in addition can also cut off the part in a single operation and eliminate the need to index the turret. For single-spindle machines, bypassing the need to index the turret can dramatically increase hourly part production rates. On long-running jobs it is common to use a roughing tool on a different slide or turret station to remove

3808-463: The pot looking fixture in which the broaches are mounted; the fixture is often referred to as a "pot". The pot is designed to hold multiple broaching tools concentrically over its entire length. The broach is held stationary while the workpiece is pushed or pulled through it. This has replaced hobbing for some involute gears and cutting external splines and slots. Straddle broaches use two slab broaches to cut parallel surfaces on opposite sides of

3876-550: The puller pulls the broach through the workpiece completely. The workpiece is then removed from the machine and the broach is raised back up to reengage with the elevator. The broach usually only moves linearly, but sometimes it is also rotated to create a spiral spline or gun-barrel rifling . Cutting fluids are used for three reasons: Fortified petroleum cutting fluids are the most common. However, heavy-duty water-soluble cutting fluids are being used because of their superior cooling, cleanliness, and non-flammability. Broaching

3944-412: The rate of cut is slightly less than the ideal rate so that the load is released on the non-cutting edge of the tool. There is some spiraling of the tool as it cuts, so the form at the bottom of the workpiece may be rotated with respect to the form at the top of the hole or profile. Spiraling may be undesirable because it binds the body of the tool and prevents it from cutting sharply. One solution to this

4012-505: The side with a longer stroke. Surface style machines hold the broach stationary while the workpieces are clamped into fixtures that are mounted on a conveyor system. Continuous style machines are similar to the surface style machines except adapted for internal broaching. Horizontal machines used to be much more common than vertical machines; however, today they represent just 10% of all broaching machines purchased. Vertical machines are more popular because they take up less space. Broaching

4080-497: The spline form to ensure precise concentricity. The cut-and-recut broach is used to cut thin-walled workpieces. Thin-walled workpieces have a tendency to expand during cutting and then shrink afterward. This broach overcomes that problem by first broaching with the standard roughing teeth, followed by a "breathing" section, which serves as a pilot as the workpiece shrinks. The teeth after the "breathing" section then include roughing, semi-finishing, and finishing teeth. For defining

4148-400: The stresses down is with chip breakers . They are notches in the teeth designed to break the chip and decrease the overall amount of material being removed by any given tooth (see the drawing above). For broaching to be effective, the workpiece should have 0.020 to 0.025 in (0.51 to 0.64 mm) more material than the final dimension of the cut. The hook ( α ) angle is a parameter of

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4216-423: The tool. The profile of the machined surface is always the inverse of the profile of the broach. The rise per tooth (RPT), also known as the step or feed per tooth, determines the amount of material removed and the size of the chip. The broach can be moved relative to the workpiece or vice versa. Because all of the features are built into the broach, no complex motion or skilled labor is required to use it. A broach

4284-405: The tooth construction, strength, and number of teeth in contact with the workpiece. The pitch is usually calculated from workpiece length, so that the broach can be designed to have at least two teeth in contact with the workpiece at any time; the pitch remains constant for all teeth of the broach. One way to calculate the pitch is: Broaching machines are relatively simple as they only have to move

4352-711: The very high cutting speeds and feeds supported by these materials, the cutting tip can reach temperatures high enough to melt the brazing material holding it to the shank. Economics are also important; inserts are made symmetrically so that when the first cutting edge is dull they can be rotated, presenting a fresh cutting edge. Some inserts are even made so that they can be flipped over, giving as many as 16 cutting edges per insert. There are many types of inserts: some for roughing, some for finishing. Others are made for specialized jobs like cutting threads or grooves. The industry employs standardized nomenclature to describe inserts by shape, material, coating material, and size. A form tool

4420-401: The work by pulling the tool into the work. Side rake along with back rake controls the chip flow and partly counteracts the resistance of the work to the movement of the cutter and can be optimized to suit the particular material being cut. Brass for example requires a back and side rake of 0 degrees while aluminum uses a back rake of 35 degrees and a side rake of 15 degrees. Nose radius makes

4488-469: The work piece rotates, the broach is pressed against it, is driven by it, and rotates synchronously with it. If the tool holder rotates, the broach is pressed against the workpiece, but is driven by the tool holder. Ideally the tool advances at the same rate that it cuts. The ideal rate of cut is defined as: If it advances much faster, then the tool becomes choked; conversely, if it advances much slower, then an interrupted or zig-zag cut occurs. In practice

4556-427: Was no longer taken for granted that the black art of individual craftsmen represented the highest level of metalworking technology. This was part of a larger trend during the 19th and 20th centuries by which science was mixed with art in the material culture of everyday life ( applied science ). Stellite soon joined high-speed steels as a material for single-point cutters. Although diamond turning had been around for

4624-412: Was originally developed for machining internal keyways. However, it was soon discovered that broaching is very useful for machining other surfaces and shapes for high volume workpieces. Because each broach is specialized to cut just one shape, either the broach must be specially designed for the geometry of the workpiece or the workpiece must be designed around a standard broach geometry. A customized broach

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