Volume 16 - Machining Part 12 pdf

Advantages and Limitations. The method of operating knee-and-column machines varies from manual control of all movements to power control of all movements. In addition, through the use of stops and other control devices, the machine can be adapted for automatic cycles. Because of their versatility in machining workpieces of different sizes and shapes, these machines are widely used for low-production milling. The main disadvantage of the knee-and-column machine is its inherent lack of rigidity. The machine has three or four joints with sliding fits, each requiring a minimum of 0.051 mm (0.002 in.) clearance. The joint between the knee and the column bears the combined weight of the knee, saddle, table, fixture, and workpiece. Deflection is therefore inevitable under milling stress. To add some rigidity and to reduce deflection, an outboard support can be placed between the overarm and the knee. To prevent chatter, limitations must be imposed on feed, speed, and depth of cut in milling. Chatter will cause a decrease in dimensional accuracy, unacceptable surface finish, and reduced cutter life. Bed-Type Machines Bed-type machines, also known as fixed-bed machines, are characterized by the extremely rigid construction afforded by a rectangular bed casting or weldment. These units are supported and leveled along their entire length, which can vary from 0.9 to 9 m (3 to 30 ft) or more. The principal components of a bed-type machine are shown in Fig. 7. These machines are almost as versatile as knee-and- column machines, and they have at least 50% greater rigidity. In a bed-type machine, the table and saddle are mounted on a bed of fixed vertical position, and vertical movement is obtained from the spindle carrier. Consequently, less weight is moved on guideways, which are about 50% longer for a given size of machine as compared to the movement of the knee. In addition, spindle overhang is reduced by as much as 75% because the cutter can be located closer to the vertical way. Bed-type machines are available in horizontal-, vertical-, and multiple-spindle versions. Fig. 7 Principal components of a horizontal-spindle bed-type milling machine Horizontal-Spindle Bed-Type Machines. The horizontal machine consists basically of a headstock or column bolted to, or integral with, a fixed bed. On this member, a spindle carrier, head, or block is mounted, carrying a spindle that is horizontally positioned. The axis of this spindle is parallel to the table surface and is at right angles to the axis of table movement. The carrier usually moves (manually or automatically) in a vertical direction on the headstock, and the spindle is adjustable axially (in and out) through a spindle quill or ram. Because of the more rugged construction of this type of machine, high-power cuts are made more easily. In addition, better surface finishes and closer machining tolerances can generally be obtained than are possible with knee-type machines. Horizontal-spindle machines are also available with tracer control to the vertical axis. This permits various shapes and contours to be generated by causing the spindle carrier or head to raise or lower at a specified time, as dictated by a cam or template mounted to the table of the machine. These units are commonly called rise-and-fall milling machines. Machining cycles can be manual or automatic and are actuated by preset dogs and electric switches or hydraulic plungers. Numerical control systems and similar systems are also frequently used, with all machine functions being programmed. Horizontal-spindle machines are designated by sizes 10, 14, 18, 22, and 30. Each size may have a range of dimensions. For each dimensional size, machines are usually made for light, medium, and heavy duty, with corresponding strength and power. Vertical-spindle bed-type machines incorporate a rigid headstock on which the entire spindle carrier can slide up and down as required. The vertical milling machine differs from the horizontal machine principally by the position of the carrier and spindle axis. A ram or spindle carrier is mounted on a rear base, which is normally fastened to the fixed bed. This carrier houses the vertical spindle, whose axis is perpendicular to the top of the table and is adjustable vertically along its own axis through a quill. The carrier assembly is sometimes fixed (with no movement) and in some cases is adjustable manually or by power to travel laterally, so that the spindle can be positioned crosswise to the table (forward or to the rear of the table centerline). The vertical machine is well suited to face milling operations and can handle heavy cuts with close tolerance and finish requirements. Although face milling and end milling are the most common operations performed on this type of machine, arbor-mounted cuts can also be made; however, these are the exception rather than the rule. As a result, the vertical machine is more limited and less versatile than the horizontal machine. For close tolerances, good finish requirements, and large-lot production with minimum time per part, the vertical milling machine, properly tooled, is a valuable asset. Tracer and numerical control can be adapted to vertical machines. These machines are available in a wide range of sizes and variations. Automatic cycles and numerous accessories are offered as options. Specific advantages of the bed-type machine in comparison with the knee-and-column machine are: • Greater rigidity, permitting heavier cuts and closer dimensional control • Constant reloading level of the table • Controls at a uniform level • Greater range of vertical movement • Versatility that can be increased by providing a longer saddle and outboard support The main disadvantage of the bed-type milling machine is its high initial cost. Simplex, Duplex, and Triplex Models. Milling machines of the bed type are designed for production and therefore are also termed manufacturing or production millers. They are available as standard models with up to 225 kW (300 hp) and can be modified or equipped as needed for mass production. On some units, the spindle carrier is a ram slide mounted on a vertical column. The machine illustrated in Fig. 8 is a simplex model (one spindle carrier). Duplex models have a headstock and spindle carrier on each side of the bed. This configuration allows the simultaneous operation of opposing cutters in a single pass, thus doubling productivity with a relatively low (about 30%) increase in investment (Fig. 9). All carrier features, speeds, feeds, and ranges are duplicated. Maintaining accurate parallelism by the two-spindle setup is one of the advantages of the duplex machine. A logical extension of the duplex model is the triplex model, which has three spindles to mill three surfaces (engine blocks, for example) simultaneously in one pass. Fig. 8 Principal components of a manufacturing-type milling machine with one spindle carrier Fig. 9 Principal components of a duplex horizontal milling machine with two horizontal spindles Planer-Type Machines Planer-type machines are so termed because of their structural resemblance to a planer. Known also as adjustable-rail or fixed-bridge milling machines, they can provide almost any combination of vertical, horizontal, or angular spindles for driving milling cutters and boring bars. Planer-type milling machine spindle drives generally range from 22 to 75 kW (30 to 100 hp). These machines can also perform several milling and boring operations simultaneously. The quill, carrying the spindle, is fed in and out for drilling and boring. Fixed-Bridge Milling Machines. The machine illustrated schematically in Fig. 10 is a triplex model (three spindle carriers). On a triplex machine, workpieces are secured to the table, which carries them back and forth between the two vertical columns and under the crossrail. Two horizontal spindle carriers move vertically on the columns, and a vertical spindle carrier moves horizontally on the crossrail. The crossrail can move vertically on the two columns. Fig. 10 Principal components of a triplex planer-type milling machine Figure 11 shows that the planer-type milling machine can utilize one to four milling spindle heads, with the spindles either parallel or perpendicular to the movement of the table. These machines overcome the inherent disadvantages of ordinary planers, which can use only single-point cutting tools and cannot be reciprocated rapidly (see the article "Planing" in this Volume). Planer-type milling machines utilize several milling heads to remove large amounts of metal while permitting the table and workpiece to move quite slowly, but they often require only a single pass of the cutters. This is a great advantage where heavy workpieces such as machine tool bases, aircraft wing spars, and missile bodies are being machined. Fig. 11 End views of planer-type milling machine configurations in addition to that shown in Fig. 10 . Top row: single-column machines with one milling spind le head (a); overhanging beam and two milling spindle heads (b); and cross slide, support stand, and one milling spindle head (c). Bottom row: double- column machines with cross beam and two milling heads (d); cross beam, cross slide, and two milling spindl e heads (e); cross beam, cross slide, and four milling spindle heads (f) Moving-Bridge or Gantry-Type Milling Machines. Some large milling machines, similar to planer-type mills, are built on the gantry principle. The workpiece is mounted on a stationary table, and the milling heads are mounted on a traveling column, also called a gantry, driven by a ball screw or a rack-and-pinion drive system (Fig. 12). The maximum working capacities of such a machine are as follows: length, 9000 mm (354 in.); width, 4900 mm (193 in.); and height, 4000 mm (157 in.). Fig. 12 Principal components of a moving-bridge or gantry-type milling machine The spindle carriers mount to a saddle that travels in the cross, or y-axis, direction on a way system. They can also be moved in the z-axis, or vertical, direction, either independently or by means of a saddle that rides on a set of vertical ways. As with planer or bridge-type machines, the number of spindle carriers is optional, and they can be mounted on either side of the crossrail. Additional axes of motions are available if required; one is usually a swivel motion in the yz- plane, and the other a swivel motion in the xz-plane. These motions can be either full contouring or positioning only, making possible the machining of complicated geometric shapes such as marine propeller blades. The crossrail is usually designed so that it can be raised for additional clearance over the work surface. Skin Mills. Gantry-type machines are a common style of structure for a variety of special machines used by the aerospace industry. These machines are used to manufacture large wing, missile, and rocket skins. The increased size of aircraft and missiles has dictated machine sizes with up to 6.1 m (20 ft) or more of work width and up to about 60 m (200 ft) of longitudinal travel. Most skins are aluminum, but in recent years skins of steel and titanium have also been manufactured by these machines. Template and honeycomb mills are another common gantry-type machine. These machines are usually smaller than a skin mill and are of much lighter construction because template and honeycomb work requires high-speed, low-torque spindle carriers. Honeycomb milling often requires a multiple-axis machine. In addition to the usual three axes (x, y, and z), one or two swivel axes are generally supplied. A spar mill is also a gantry-type machine, usually with a long longitudinal travel but a very narrow work surface (610 to 914 mm, or 24 to 36 in.). Spar mills usually have horizontal spindles with a swivel axis of motion and/or a vertical spindle, also with a swivel motion. This swivel motion is essential because of the warps inherent in aircraft spars. Recent spar mills have been designed to mill aluminum, steel, or titanium spars. Some seven-axis CNC spar mills are capable of milling workpieces that are 33 m (108 ft) long, and they can machine a pair of opposite-hand (mirror-image) workpieces simultaneously with two spindles. The gantry-type machine offers several advantages over the planer or fixed-bridge construction. The gantry-type machines maintain the inherent stiffness of the closed-type construction of a bridge machine, thus allowing for heavy cuts with minimum deflection. With x-axis travels exceeding the upright length, the gantry machine offers floor-space savings over a similar bridge type. The gantry machine also presents a stationary work surface that facilitates double loading and offers the option of extending the beds for additional x-axis travel. This adding of bed sections can take place later if desired. Many installations of gantry machines have several gantries with overlapping travels on one long continuous bed. The chip removal and coolant problems of gantry-type machines are similar to those of the fixed-bridge machines. However, because the gantry-type machines are usually longer and have a way system running along each side of the bed, the problems are somewhat magnified. Again, as with the fixed-bridge machines, the operator must be positioned on the work surface, or the spindles must be moved to an extreme y-axis position to replace or exchange cutters. Planer-type machines are large and represent a major capital investment. Therefore, their use is generally restricted to removing large amounts of metal from massive workpieces such as mill or power-plant components or to mass- production milling in which identical workpieces are arranged in a row to be milled together. Tables are often split to permit simultaneous setup and milling of the work. Special-Purpose Machines Innumerable special-purpose milling machines have been designed and built, sometimes for use on special workpiece configurations, but more often for high-volume production of a specific part. Most special-purpose machines are combinations of two or more of the basic machines described earlier in this article. The cost of special-purpose milling machines can be justified only for the continuous high production of identical workpieces or if several operations can be combined in one handling to reduce manufacturing costs. Specially designed machines are usually more readily adapted to automatic control than are standard machines, although standard machines can be automated to various degrees. Special-purpose machines include the following: • Profilers • Duplicators (die sinking machines) • Rotary millers • Planetary millers Profilers. Milling machines that can duplicate external or internal profiles in two dimensions are called profilers or tracer-controlled contouring machines. As shown in Fig. 13, a tracing probe follows a two-dimensional template and, through electronic or air-actuated mechanisms, controls the cutting spindles in two mutually perpendicular directions. The spindles (usually more than one) are set manually in the third dimension. Fig. 13 Principal components of a vertical-spindle profiler Duplicators produce forms in three dimensions. A tracing probe follows a three-dimensional master. Often the probe does not actually contact the master; a variation in the length of a spark between the probe and the master controls the drives to the quill and the table, thus avoiding wear on the master or possible deflection of the probe. On some machines, the ratio between the movements of the probe and cutter can be varied. Duplicators are widely used to machine molds and dies. They are extensively used in the aerospace industry to machine parts from wrought plate or bar stock as substitutes for forgings; in such cases, the small number of parts required would make the cost of forging dies uneconomical. To a great extent, profilers and duplicators have been replaced by NC machines, in which a punched tape or a computer input eliminates the need to make a template or a master mold. Die shops are also using double-column, table-type vertical/horizontal portal-type machines in place of profilers and duplicators. Rotary millers, usually of the vertical-spindle type, are used for such operations as contour and slab milling, channeling, milling tongues and jaws, trepanning, and end milling. These machines, however, are suited primarily to the production of large, heavy components in small or medium quantities. Where mass production is contemplated on parts with surfaces that can be face milled in a single pass, a single-purpose type of rotary miller is employed. Jigs or fixtures mounted on the table provide for virtually continuous cutting; parts are loaded, passed first beneath the roughing and then the finishing spindle, and automatically released for replacement with a rough part. Rotary-Table Milling Machines. Some types of face milling in mass-production manufacturing are often done on rotary-table milling machines. These machines are adaptations of the vertical milling machine to a specialized use. In this case, there are two vertical spindles, each equipped with a facing mill. Cylinder heads, for example, are roughed at the first station and then finish milled as they pass the second station, while the workpiece is held in fixtures on the rotating table. The operation is continuous, and there is ample time for the operator to load and unload the machine during the milling. This machine is fast but is limited to the milling of flat surfaces. The rotary-head milling machine is an unusual departure from conventional rotary machines. Suited primarily to tool, die, and small-quantity production, this miller adds to the versatility of the rotary-table machine but is designed for much smaller parts. Intricate radial cam work can be readily produced from drawings without the use of templates. Rotary-Drum Milling Machine. Having as many as five horizontal spindles, this machine is designed for the mass production of large parts such as motor blocks, gear cases, and clutch housings. On these machines, parts are carried in fixtures mounted on a drum, which rotates continuously, carrying the parts between adjustable face mills. The rotary vertical-offset milling machine also uses a rotating table with fixtures. Cutters are carried on a short vertical spindle, which rotates on an axis eccentric to the table axis. Suited primarily to the production of small machine parts, the offset miller can perform facing, slotting, sawing, straddle milling, and some simple form milling. Planetary milling machines, also known as eccentric-drum millers, employ eccentric drums that carry the milling spindle. These units are so named because of the automatic planetary action obtained (Fig. 14). Adapted to internal or external thread milling where high production is contemplated, the planetary machine simplifies the manufacture of parts that are difficult to hold on swing. It also simplifies the production of concentric bores or diameters, either plain or threaded. Both cutter rotation and feed are provided by the eccentric drums; the part being milled is held stationary during the processing. For thread milling with multiple-thread mills, the drums are provided with a lead screw feed, and they finish an entire thread in one and a small fraction of a revolution. The work possible ranges from about 7.9 to 508 mm ( to 20 in.) diameter and from about 16 to 508 mm ( to 20 in.) in inside diameters with thread leads up to 28.58 mm (1.125 in.). Length of milled surfaces in most cases should not exceed 1 to 1 times the diameter. For special operations, many single-purpose variations of the planetary principle in both horizontal and vertical models are employed. However, in most cases, these machines require special cutters and fixtures and are therefore suited primarily to mass-production output. Fig. 14 Planetary action and cutter path of an eccentric- drum miller. (a) Internal work. (b) External work. Cutter is shown in neutral position for loading (left), in radial feed to depth (center), and in planetary feed around work (right). Machining Centers. In terms of construction, many machining centers are similar to the basic types of manual milling machines discussed earlier (see the section "Machining Centers" in the article "Multiple-Operation Machining" in this Volume). Some small machining centers are patterned closely after the ram-type milling machine. Vertical-spindle machining centers in the medium size category are constructed similarly to fixed-bed vertical milling machines. Both fixed-bed and gantry-type planer milling machines are commonly fitted with numerical controls, although this type of machine does not meet the definition of a machining center. Medium-size horizontal-spindle machining centers, on the other hand, do not have a common manual twin; the bed is fixed, but the machine is capable of more motions than all but a few fixed-bed horizontal machines. A table and saddle combination provides feed motion in the longitudinal direction and to and from the column face. Vertical-spindle feed is provided by mounting the spindle carrier on column ways or by mounting the spindle in a quill. The machining center offers a number of basic advantages relative to manual milling machines. Productivity is generally much higher, even though metal removal rates may vary only slightly. The reason is that the machining center generally spends about 70 to 80% of its time cutting chips, compared to about 20 to 30% for a manual milling machine. The reasons for this include the following: • The machining center can perform many different operations in addition to milling; this often eliminates the need to move the part to another machine • It can work on several sides of the part without a new setup • It can often accurately hold close tolerances and relationships without special jigs or fixtures The machining center also provides for greater repeatability than a manual milling machine. Although a highly skilled machinist can hold very close tolerances on a manual machine, a machining center can hold close tolerances day after day, without depending on the skill and attentiveness of the machinist. Furthermore, a tape can be put away and reused several months later; it will still produce identical parts. The configuration of the part is extremely important in determining whether it would be most efficiently produced on a manual milling machine or on a machining center. The following types of parts are generally well suited to machining centers: • Parts machined on several faces • Parts requiring a large number of operations • Parts with close tolerances • Parts in which design changes are anticipated • Parts that are very expensive (because a machining center rarely produces a scrap part It should be noted that nearly all the advantages attributed to machining centers also apply to automated batch- manufacturing systems and transfer lines. Machining centers are most useful in small production runs in which each batch differs significantly from the others. Optimization of Milling Machine Setup Setup often accounts for most of the time required in milling one or a few pieces. When a variety of work is to be milled, time can be saved by planning and scheduling the jobs so that similar parts are milled in succession. A milling machine can be tooled in different ways to obtain the lowest cost with different quantities of pieces. Some common milling arrangements are illustrated in Fig. 15. Fig. 15 Common forms of production milling operations Plain, or simple, milling (Fig. 15a) involves the loading and milling of one piece at a time and is the usual arrangement for one or a few pieces. Cutting time is saved in string, or line, milling (Fig. 15b) by having two or more pieces arranged in a row because the cutter can enter one piece as it leaves another. Efficiency is achieved by arranging for the operator to [...]... 2-4 2-4 2-4 Radial relief angle, degrees 5-8 5-8 5-8 1 0-1 2 1 0-1 2 5-1 2 5-1 2 3-5 2-4 4-8 3-7 -5 to -1 0 -5 to -1 0 0 to -1 0 0 to -1 0 2-5 2-4 5-8 3-6 1 0-1 2 5-1 2 2-4 3-7 -5 to -1 0 0 to -1 0 2-4 5-8 1 0-1 2 0-5 1 0-1 2 5-1 2 0-5 5-1 2 2-4 2-4 3-5 3-7 3-7 4-8 -5 to -1 0 -5 to -1 0 0 to -5 0 to -1 0 -5 to -1 0 0 to -1 0 2-4 2-4 2-4 3-6 3-6 5-8 1 0-1 2 5-1 2 3-5 4-8 0-5 -5 to 5 2-4 5-8 1 0-1 2 5-1 2 3-5 4-8 0-5 -5 to 5 2-4 5-8 ... 135 HB-52 HRC 135 HB-52 HRC 15 0-4 50 1 0-1 2 5-1 2 2-4 3-7 -5 to -1 0 0 to -1 0 2-4 5-8 1 0-1 2 5-1 2 2-4 4-8 0 to -5 0 to -1 0 2-4 5-8 10 0-4 00 1 0-1 2 1 0-1 2 2-4 3-7 0 to -1 0 5 to -1 0 3-5 5-8 3 0-1 50 (500 kg) 4 0-9 0 (500 kg) 11 0-4 40 4 0-2 00 (500 kg) 8 0-3 60 14 0-3 00 30 0-4 75 17 0-2 90 1 2-2 5 1 0-2 0 5-7 5-1 1 1 0-2 0 5-1 5 5-7 7-1 0 1 2-2 5 1 0-2 0 5-7 5-1 1 1 0-2 0 5-1 5 5-7 7-1 0 1 0-1 5 1 2-2 5 5-1 0 1 0-2 0 5-7 5-7 5-1 1 5-1 1 0 to -1 0 1 0-2 0... 15 0-4 50 5-1 0 5-1 0 5-7 0-5 0 0 45 5 8-1 0 8-1 0 10 0-4 00 2 0-3 0 -5 to 10 5-1 1 -5 to 11 5-1 0 5 to -1 0 45 5-1 0 4-7 4-7 3 0-1 50 (500 kg) 2 0-3 5 2 0-3 5 5-7 0-5 1 0-2 0 1 0-2 0 45 7-1 2 3-5 1 0-1 2 4 0-9 0 (500 kg) 2 0-3 5 2 0-3 5 5-7 0-5 1 0-2 0 1 0-2 0 45 7-1 2 3-5 1 0-1 2 11 0-4 40 5 5 0 to -5 0 to -5 0 to -5 -1 0 45 6-1 2 1 0-1 2 1 0-1 2 4 0-2 00 (500 kg) 1 2-2 5 1 0-1 2 5-7 0-5 3-1 0 3-1 0 45 7-1 2 3-5 5-1 0 8 0-3 60 7 15 5-1 1 -5 to 14 5-1 0 0 to -5 ... 5-7 5-7 5-1 1 5-1 1 0 to -1 0 1 0-2 0 0 to -1 0 5-1 0 5-7 4-7 5-8 5-8 1 0-2 0 1 0-1 5 1 0-1 2 0 1 0-1 5 1 0-1 5 5-1 2 1 5-2 0 3-5 1-5 1-5 3-5 4-8 5-1 0 4-8 5-1 0 -5 to -1 0 -5 to -1 0 -5 to -1 0 0 0 to -1 0 0 to -1 0 0 to -1 0 5-1 5 3-5 3-5 3-5 7-1 0 5-8 5-8 5-8 7-1 0 20 0-2 50 0 1 5-2 0 3-5 5-1 0 0 5-1 5 7-1 0 7-1 0 18 0-3 20 5-1 5 1 0-1 5 1 0-1 5 8 0-1 00 1 0-2 0 1 0-2 0 5-7 8-1 1 -1 0 to 15 1 0-1 5 1 0-1 5 7-1 0 7-1 0 Source: Metcut Research Associates... Radial primary relief angle, degrees Primary land width mm in 1.6 2 0-2 1 3 0-3 5 2 0-2 2 3 1 2-1 3 2 2-2 8 1 4-1 8 4 1 2-1 3 2 0-2 5 1 4-1 8 6 1 0-1 1 2 0-2 5 1 2-1 5 7 1 0-1 1 2 0-2 5 1 2-1 4 8 1 0-1 1 1 7-2 0 1 2-1 4 10 9-1 0 1 7-2 0 1 1-1 3 12 9-1 0 1 7-2 0 1 1-1 3 14 9-1 0 1 7-2 0 1 1-1 3 16 8-9 1 5-1 8 1 0-1 2 20 8-9 1 5-1 8 1 0-1 2 1 5-1 8 1 0-1 2 1 3-1 8 9-1 1 1 1-1 7 9-1 1 10 -1 6 8-1 0 9-1 5 8-1 0 0.180.25 0.250.38 0.250.51 0.250.51 0.380.64 0.380.64 0.510.76 0.510.76... edge angle, degrees 5-1 0 5-7 3-7 0 to -7 30 5-1 0 5-7 3-7 0 to -1 0 0 to -1 0 30 5-1 0 5-7 3-7 -5 to 15 -5 to 15 -5 to 15 -5 to 15 0 to -1 0 45 4-7 5-7 3-7 45 4-7 8 8 45 4-7 5-7 3-7 45 4-7 8 8 45 5-1 0 5-7 3-5 45 4-7 5-7 3-5 0 -5 to 15 -5 to 15 -5 to 15 -5 to 15 -5 to 15 -5 to 15 0-5 45 5 8-1 0 8-1 0 0 0 to -5 45 5 8-1 0 8-1 0 0-5 0 to -5 45 5 8-1 0 8-1 0 0 0 to -5 45 5 8-1 0 8-1 0 0 to -1 0 Corner angle, degrees Wrought... 15 5-1 1 -5 to 14 5-1 0 0 to -5 45 5 7-9 7-9 21 0-3 40 (4 8-6 0 HRC) 20 0-4 75 5-7 0-5 0 0 45 10 12 12 5-1 0 5-1 0 0-5 0 to -5 0-5 0 to -5 45 5 7-1 0 7-1 0 17 0-2 25 0 20 5-7 0-5 0 10 45 5-1 0 10 10 22 0-2 90 0 20 5-7 0-5 0 0 45 5-1 0 10 10 20 0-2 50 0 20 5-7 0-5 0 0 45 5-1 0 10 10 18 0-3 20 -4 to -8 -3 to 11 -1 5 0 45 5-1 0 15 15 8 0-1 00 1 0-1 5 1 0-1 5 5-7 0-5 1 0-1 2 1 0-1 2 45 7-1 2 10 1 0-1 2 Source: Metcut Research Associates... Hardness, HB 8 5-3 25 32 5-4 25 4 5-5 2 HRC 12 5-4 25 4 5-5 2 HRC 100 HB-52 HRC 20 0-3 50 25 0-3 20 100 HB-50 HRC 13 5-4 25 High-speed steel Axial Radial rake rake angle, angle, degrees degrees 1 0-1 5 1 0-1 5 1 0-1 2 5-1 2 1 0-1 2 5-1 2 Axial relief angle, degrees 3-5 3-5 2-4 Radial relief angle, degrees 4-8 4-8 3-7 Carbide Axial rake angle, degrees 0 to -5 0 to -5 -5 to -1 0 Radial rake angle, degrees -5 to 5 -5 to 5 0 to -1 0 Axial... freemachining stainless steels Wrought and cast ferritic and austenitic stainless steels Wrought and cast martensitic stainless steels 4 5-5 8 HRC 20 0-3 50 -4 to -8 5-1 0 5-1 0 -4 to -8 25 0-3 20 0-5 0-5 -4 to -8 13 5-2 75 1 0-1 5 1 0-1 2 5-1 1 27 5-4 25 5-1 0 5-1 0 5-1 1 13 5-2 75 1 0-1 5 1 0-1 2 5-1 1 13 5-4 25 5-1 0 5-1 0 5-1 1 Axial relief angle, degrees Radial relief angle, degrees 30 End cutting edge angle, degrees 5-1 0 5-7 ... 27 0-3 25 1 0-1 5 1 0-1 5 -4 to -8 -3 to 11 0 to -7 32 5-4 25 1 0-1 2 1 0-1 2 -4 to -8 4 3-5 0 HRC 5 0-5 6 HRC 22 5-4 25 5-1 0 5-1 0 -4 to -8 -4 to -8 5-1 0 0-1 0 -4 to -8 -3 to 11 -3 to 11 -3 to 11 -3 to 11 -3 to 11 -3 to 11 -3 to 11 -5 to 11 -5 to 11 -5 to 11 -5 to 11 Material Hardness, HB Wrought and cast freemachining carbon steels and carbon steels Wrought and cast freemachining alloy steels and alloy steels Wrought . 4 5-5 2 HRC 1 0-1 2 5-1 2 2-4 3-7 -5 to -1 0 0 to -1 0 2-4 5-8 12 5-4 25 1 0-1 2 5-1 2 3-5 4-8 -5 to -1 0 0 to -1 0 2-5 5-8 Wrought and cast alloy steels 4 5-5 2 HRC 1 0-1 2 5-1 2 2-4 3-7 -5 to -1 0 0 to -1 0. 20 0-3 50 5-1 0 5-1 0 -4 to -8 -3 to - 11 0 to -1 0 -5 to - 15 45 5-1 0 5-7 3-5 Wrought armor plate 25 0-3 20 0-5 0-5 -4 to -8 -3 to - 11 0 to -1 0 -5 to - 15 45 4-7 5-7 3-5 13 5-2 75 1 0-1 5. 5-1 1 1 0-2 0 5-1 0 4-7 5-8 Wrought and cast nickel alloys 8 0-3 60 1 0-2 0 1 0-1 5 3-5 4-8 -5 to -1 0 0 to -1 0 3-5 5-8 14 0-3 00 1 0-1 5 1 0-1 5 1-5 5-1 0 -5 to -1 0 0 to -1 0 3-5 5-8 Wrought and cast high- temperature