2-D or 3-D path generated by program code or a CAM system and followed by tool when machining a part.

Cylindrical sleeve, typically made from high-grade tool steel, inserted into a jig fixture to guide cutting tools. There are three main types: renewable, used in liners that in turn are installed in the jig; press-fit, installed directly in the jig for short production runs; and liner (or master), installed permanently in a jig to receive renewable bushing.

Available in two major types: tungsten high-speed steels (designated by letter T having tungsten as the principal alloying element) and molybdenum high-speed steels (designated by letter M having molybdenum as the principal alloying element). The type T high-speed steels containing cobalt have higher wear resistance and greater red (hot) hardness, withstanding cutting temperature up to 1,100º F (590º C). The type T steels are used to fabricate metalcutting tools (milling cutters, drills, reamers and taps), woodworking tools, various types of punches and dies, ball and roller bearings. The type M steels are used for cutting tools and various types of dies.

Someone who can speak to this is Bill Jones, president of Enderle Fuel Injection Inc., Simi Valley, Calif. He recently broke a tool he’d been using for the past 10 years. “I was hoping to get an 11th year out of it,” he laughed.

“With indexable cutters, you need a couple of spare inserts and screws,” he said. “And there’s no need to spot-drill, drill and rough the port form as there is with traditional port tools. You just come in and drill, and the port’s ready to go. Because you’re not worried as much about tool life, you can be a bit more aggressive on feeds and speeds. The end result is a lower cost per part.”

Condition of vibration involving the machine, workpiece and cutting tool. Once this condition arises, it is often self-sustaining until the problem is corrected. Chatter can be identified when lines or grooves appear at regular intervals in the workpiece. These lines or grooves are caused by the teeth of the cutter as they vibrate in and out of the workpiece and their spacing depends on the frequency of vibration.

Port tools can be resharpened many times and, according to Wetmore Tool, may last decades. Photo courtesy of Wetmore Tool and Engineering.

Cone-shaped pins that support a workpiece by one or two ends during machining. The centers fit into holes drilled in the workpiece ends. Centers that turn with the workpiece are called “live” centers; those that do not are called “dead” centers.

Cooling and lubricating coolants can reduce the temperature of the material being cut and improve chip removal.

So what about cam machines that are 20 or 30 years old or older? Truth is, many companies still run older cam-style machines, and these machines aren’t being ignored. There are new options for them too.

Turning application technology has come a long way from the time when you simply clamped a piece of tool steel in place for a turning application. Today the flexibility, simplicity, increased stability or rigidity, and improved accuracy are making modular grooving systems popular.

Essentially a cantilever beam that holds one or more cutting tools in position during a boring operation. Can be held stationary and moved axially while the workpiece revolves around it, or revolved and moved axially while the workpiece is held stationary, or a combination of these actions. Installed on milling, drilling and boring machines, as well as lathes and machining centers.

Machining and measuring to exacting standards. Four basic considerations are: dimensions, or geometrical characteristics such as lengths, angles and diameters of which the sizes are numerically specified; limits, or the maximum and minimum sizes permissible for a specified dimension; tolerances, or the total permissible variations in size; and allowances, or the prescribed differences in dimensions between mating parts.

Workholding device that affixes to a mill, lathe or drill-press spindle. It holds a tool or workpiece by one end, allowing it to be rotated. May also be fitted to the machine table to hold a workpiece. Two or more adjustable jaws actually hold the tool or part. May be actuated manually, pneumatically, hydraulically or electrically. See collet.

Whether you’re a truck driver, a commercial airline pilot or a snowmobiler, a leaky hydraulic system or fuel line can spell big trouble. A little fluid in the wrong place on these and a host of other vehicles and machinery might create a life-or-death situation for operators and passengers alike.

Enderle applies SCT tools to port barrel valves, fuel shutoffs, fittings and other racing equipment components. Most of these are made of 6061-T6 aluminum, although Jones said Enderle machines some cast aluminum, which is somewhat abrasive. Still, he and his team have “zero problems” with tool life or chatter—success that Jones attributed to a rigid setup and high-quality cutting tools.

A mock-up of a ported agricultural valve body for a trade show presentation. Image courtesy of New Dimensions Precision Machining.

Coolant applied through the toolholder is precisely directed to the cutting edge, where it will have the most impact on the cutting process.

One of the biggest challenges with any porting operation is chatter. SCT’s Christopher said a 3-flute port tool is often effective in combating chatter. However, the feed rate is sacrificed because there’s one less edge in the cut compared to the more-common 4-flute port tool. “That’s why we take a diamond brush hone to all our tools,” he said. “This puts a microscopic edge break on the sharp edges. [It is] a little like rubbing a penny or a Scotch-Brite pad on the tool’s spot face, a trick that many veteran machinists are familiar with.”

The negative chip angle that works so well in free-machining brass does not work nearly the same in the lead-free version. Machining trials have shown that lead-free brass is best machined with geometries more suited for steel. For the best process capability it is important to apply the correct geometries and grades for the material you are machining. Not all brass is the same.

Grooving and parting-off applications present unique challenges. Unlike a longitudinal turning application that allows chips to move in three directions without restrictions, during grooving and parting-off processes you are machining between flanks, which confine chip movement to just two directions.

Automated manufacturing system designed to machine a variety of similar parts. System is designed to minimize production changeover time. Computers link machine tools with the workhandling system and peripherals. Also associated with machine tools grouped in cells for efficient production. See cell manufacturing.

Hartland Cutting Tools Inc., Cary, Ill., is near New Dimensions. Owner Mike Polizzi said he provides solid and carbide-tipped port tools, although HSS and indexable versions are available from other suppliers. Customers must also decide on the style of tool to apply:

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It is important to consider the economics of parting off. Since parting off is often the final operation in manufacturing a component, reliability is crucial.

The P-style blades have many options with indexable blades that are designed to fit in existing tool blocks. Solid-carbide options allow for direct replacement of these blades for groove and cutoff applications.

What about port tools with indexable carbide inserts? Solid-carbide and brazed tool aficionados might disagree, but for many applications, indexable tools are suitable. “Aside from the threads, our tool cuts the entire port in one operation,” said Rob Brown, product manager at Allied Machine and Engineering Corp., Dover, Ohio. “When it gets dull, you just change out the insert and go back to work. You don’t have to worry about regrinding or knocking out the old carbide and brazing in new pieces.”

“We still see a fair amount of activity with standard brazed porting tools, but it’s not like it once was,” Kurtz said. He added that cartridge cavity tools remain fairly strong. “These are quite similar to port tools but larger, to accommodate a two-, three- or four-way hydraulic valve body that might be used to control a backhoe, for example.”

“Port tools have become quite specialized and high-performance over the years,” Polizzi said. His company still offers the same standard tools that were in use 30 years ago. However, according to Polizzi, companies like Eaton, Vickers, Hydac and Sun Hydraulics have all developed their own application-specific geometries. “Most of these are straight-flute tools, but some have a slight helix to improve finish and size control. Sometimes we’ll grind the flutes off-center a small amount for customers machining a lot of aluminum.”

Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.

Cooling lubricants and cutting fluids can dramatically affect the reliability of grooving and parting-off processes. When applied correctly, cooling lubricants can reduce the temperature of the material being machined and improve chip removal. Keep in mind that no matter how much coolant is poured on an application, or how effective the coolant is, it will have little to no effect if it is not applied to the cutting edge.

Polizzi said most of his clients want through-coolant tools, something he heartily endorses. He recommends 1,000 psi, whenever possible, and the use of a high-quality toolholder, preferably a hydraulic chuck rather than an endmill holder. “Drill the port, dwell for a second or two at the bottom of the hole and you’ll be in good shape.”

Grooves and spaces in the body of a tool that permit chip removal from, and cutting-fluid application to, the point of cut.

Brown said indexable cutters are also more cost effective. Each insert costs around $35 to $70, and a dual-insert cutter body runs roughly $600, depending on the size. This is about twice the cost of a comparable brazed tool, but Brown said users of traditional port tools need to have multiple cutters: one in the machine, a spare in the toolcrib and one out for regrinding.

ISCAR's QUICK-D-MILL NEW Combined Functions for Drilling and Milling In One Single Cutter for Maximum Machining Efficiency.

Let’s use a lead-free brass alloy as an example of a challenging material. Brass is known for its good machinability properties. A leaded, free-machining brass is particularly popular in the production of turned parts. Tools used to machine free-machining brass have a negative chipping angle that produces small, short chips. With new laws that regulate the use of hazardous materials such as lead, new grades of lead-free brass have emerged that require a change in machining processes.

Machine designed to rotate end-cutting tools. Can also be used for reaming, tapping, countersinking, counterboring, spotfacing and boring.

This is good advice. Anyone who’s used port tools knows that they generally work best after a short wear-in period. They also last a surprisingly long time.

Coolant can be supplied by an external or internal means. When external coolant is supplied via nozzles spraying on the toolholders, only a small amount of the coolant actually gets to the cutting edge so it has less of an effect on the cutting application than coolant delivered using a through-coolant toolholder delivery system. This is especially true when machining deep grooves and working with materials that are easily work-hardened, such as superalloys and stainless steels.

Coolant supplied below the cutting edge will reduce the cutting zone temperature while minimizing flank wear. This also aids in chip removal. Reducing the temperature makes it possible to use tougher varieties of inserts while maintaining tool life and cutting parameters or, in some cases, increasing tool life and improving process reliability. This process also delivers the best results when engagement times are long and temperature is a limiting factor.

The pre-plumbed systems simply bolt on to accommodate many coolant delivery options that offer quick changeover without the need to hook up coolant lines. Many of the modular systems also allow for center height adjustability that can be especially helpful when cutting difficult materials. A large number of combinations are possible with a relatively small number of components, which enables standard tool systems to be used throughout an entire production process regardless of the machine interface.

Other port tools have also seen a decline in popularity. Kurtz said the company has a long history of manufacturing port tools, but much of the work has dried up as aircraft designers move away from specifying hydraulic control systems in favor of electronic ones. As a result, Wetmore has redirected most of its development efforts into aircraft assembly tools, such as extension and core drills.

Materials are changing, and they are generally not getting easier to machine. Challenging materials such as heat-resistant superalloys, stainless steels, and lead-free alloys such as brass pose new challenges that demand modern machining strategies.

As with any indexable cutting tool, these port tools increase uptime. Just change the insert and go back to work. Image courtesy of Allied Machine and Engineering.

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Coolant from above can greatly improve chip control, which is a key to longer tool life. It can also reduce built-up edges (BUE).

Consider two key points to avoid problems. One is chip forming and the other is chip control. Good chip forming ensures that the material is plastically deformed by the tooling so the chips are narrower than the width of the cutting insert to avoid damage to the groove flanks. An example is a 5-mm-wide groove insert that creates a chip that is 4.85 mm wide.

When internal coolant is supplied directly through the toolholder, it is directed precisely to the cutting edge, enabling a much more reliable process. Internal coolant, or through-coolant, holders are available in many variations. Some direct the coolant to immediately above the insert, some to immediately below.

The 19-machine FMS at New Dimensions produces a variety of aluminum and cast iron hydraulic manifolds for the agriculture and construction industries. Image courtesy of New Dimensions Precision Machining.

New modular tools make it possible to produce assemblies that are tailored for specific applications while being made up of completely standard components. This can reduce the need for special tools. These systems provide a stable structure, while their modular design gives you flexibility and a large variety of tool configuration options.

Turning machine capable of sawing, milling, grinding, gear-cutting, drilling, reaming, boring, threading, facing, chamfering, grooving, knurling, spinning, parting, necking, taper-cutting, and cam- and eccentric-cutting, as well as step- and straight-turning. Comes in a variety of forms, ranging from manual to semiautomatic to fully automatic, with major types being engine lathes, turning and contouring lathes, turret lathes and numerical-control lathes. The engine lathe consists of a headstock and spindle, tailstock, bed, carriage (complete with apron) and cross slides. Features include gear- (speed) and feed-selector levers, toolpost, compound rest, lead screw and reversing lead screw, threading dial and rapid-traverse lever. Special lathe types include through-the-spindle, camshaft and crankshaft, brake drum and rotor, spinning and gun-barrel machines. Toolroom and bench lathes are used for precision work; the former for tool-and-die work and similar tasks, the latter for small workpieces (instruments, watches), normally without a power feed. Models are typically designated according to their “swing,” or the largest-diameter workpiece that can be rotated; bed length, or the distance between centers; and horsepower generated. See turning machine.

“Porting is pretty straightforward otherwise,” he said. “But when the tool breaks through into a neighboring hole, it tends to lose stability, causing problems with straightness and position.” Halwix added that roundness is also a concern, especially when maintaining a 0.33 Cpk allowance of ± 0.0013" (0.03mm). “The hole can easily end up egg-shaped if you don’t control the cutting forces.”

We can’t talk about coolant delivery without talking about coolant pressure. With the right coolant pressure it is possible to influence chip formation in grooving and parting off. Coolant pressure as low as 5 bar (72 PSI) can start to reduce crater wear. As the pressure increases to 20 bar (290 PSI), it can reduce BUE. Coolant pressure of 40 bar (580 PSI) can influence chip control and direction. High pressure application of 80 bar (1,160 PSI) or more can aide in chipbreaking.

Substance used for grinding, honing, lapping, superfinishing and polishing. Examples include garnet, emery, corundum, silicon carbide, cubic boron nitride and diamond in various grit sizes.

Keep up to date with the latest news, events, and technology for all things metal from our pair of monthly magazines written specifically for Canadian manufacturers!

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The narrowest indexable inserts should be used in the parting-off process as this can factor into significant material cost savings. These savings multiply exponentially when you are machining alloys that have a substantially higher material cost, such as high-temp superalloys.

Kip Hanson is a contributing editor for Cutting Tool Engineering magazine. Contact him by phone at (520) 548-7328 or via e-mail at kip@kahmco.net.

Another porting success story comes from Union, Ill. Brian Halwix Sr., director of manufacturing engineering at New Dimensions Precision Machining Inc., said the company produces a variety of aluminum and cast iron hydraulic manifolds for the agriculture and construction industries on its three Makino flexible-manufacturing systems, which utilize 19 horizontal machining centers. For Halwix, the biggest challenge with port machining is breaking into cross-holes.

Some fluid connectors come with O-rings, others with metal-on-metal seals, but all rely on a complex shape that is usually machined with a port tool.

Chip control ensures that chips will not cause problems during the machining process. The goal is to produce short helical, spiral, comma, or tear chips (shaped like 6s and 9s). These types of chips are more likely to provide stability in the grooving and parting-off process.

That’s why organizations like SAE (Society of Automotive Engineers) and ISO (International Standards Organization) have developed a series of standards that make even the highest-pressure, most-demanding fluid connection leak-free. These include SAE J1926, SAE J514, MS 33649/SAE AS5202, ISO 6149 and other technical documents that describe threaded connections.

Secures a cutting tool during a machining operation. Basic types include block, cartridge, chuck, collet, fixed, modular, quick-change and rotating.

Enlarging a hole that already has been drilled or cored. Generally, it is an operation of truing the previously drilled hole with a single-point, lathe-type tool. Boring is essentially internal turning, in that usually a single-point cutting tool forms the internal shape. Some tools are available with two cutting edges to balance cutting forces.

Milling cutter held by its shank that cuts on its periphery and, if so configured, on its free end. Takes a variety of shapes (single- and double-end, roughing, ballnose and cup-end) and sizes (stub, medium, long and extra-long). Also comes with differing numbers of flutes.

Editor’s Note: This article was developed from information presented during the Horn Technology Days 2017 event held at Paul Horn GmbH in Tübingen, Germany, May 10-12.

Nor are ports as complex as they initially appear. “It’s really just a series of diameters and angles,” he said. “Sometimes you’ll have radii callouts and sealing surfaces with tight finish requirements. Because ports are used with a connector, there’s a thread somewhere, usually at the bottom, that can be tapped, thread-milled or single-pointed if you’re turning the part on a lathe.”

“Porting on a drill press or transfer line requires a tool with a ground body so it can slide into a bushing mounted in a drill plate to guide the tool into the workpiece,” said Phil Kurtz, vice chairman of the board at Wetmore Tool and Engineering Co., Chino, Calif. “But those tools are rarely used anymore because hardly anyone uses drill presses. Virtually everything is made on CNC machines today.”

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Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.

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Through-coolant holders eliminate the need to adjust coolant lines and always direct the coolant to the tool’s cutting edge. External coolant lines can be bumped out of alignment while operators are changing tools or loading parts, which can cause process variation or premature tool failure.

For those scratching their heads over the bewildering array of port specifications, the situation’s not as complicated as it first seems. “The military came up with a standard hydraulic connector many years ago for connecting hose lines to hydraulic fittings,” Christopher said. “That was the start of the MS (mil-spec) standards. Some are still the original Army or Navy design, but quite a few have been replaced by SAE numbers.”

Machining vertical edges of workpieces having irregular contours; normally performed with an endmill in a vertical spindle on a milling machine or with a profiler, following a pattern. See mill, milling machine.

Halwix said there are two ways to avoid this problem. The first is proper part processing, particularly machining ports in the right order to avoid cross-holes in the first place. The next course of action is tweaking the tool design by adjusting flute margins and using other tricks of the porting trade. “It’s all about cutter technology,” he said. “That’s why probably 30 percent of our tools are custom, which we designed in-house based on our own education and experience.”

Porting is not rocket science. However, the configurations are sufficiently complex that they would be extremely challenging to make on most machines without what is essentially a big form tool. CNC lathes make it possible to shelve port tools in favor of a boring bar and CAM-generated toolpath. Still, port tools remain commonplace on machining centers, mechanical screw machines and even drill presses, where profiling the port shape is impossible.

Dale Christopher, president of Scientific Cutting Tools Inc. (SCT), Simi Valley, Calif., said his father built the business on port tools. Even though that source of revenue has fallen relative to the other types of cutting tools the company now offers, there’s still plenty of demand from hydraulic-manifold manufacturers, automotive and aerospace customers, and electromechanical equipment suppliers.