Then we moved to some heavier-duty 7-gauge flat stock, again testing how each bit made it through the test. We did our best to maintain similar speeds and pressure throughout each portion of every test. Afterward, we did our best to hand sharpen each of the larger bits with a file. The bits that passed these tests were given awards based on their strengths.

Those looking for an all-around capable set of drill bits may want to check out the Bosch black oxide metal drill bit set. Manufactured from high-speed steel and coated in black oxide, Bosch drill bits can withstand friction and heat so you can drill continuously without the bits heating up.

Added George Bursac, general manager of Star CNC Machine Tool Corp. (Roslyn Heights, NY), “Automation has been part of medical manufacturing for some time and is expanding based on new requirements.” While medical components like bone screws, dental implants, surgical instruments and other components associated with those products “are staying the same without many changes,” he said, “our team is responding to any new challenges manufacturing companies may require.”

Constant refinement of medical machining from tooling design to finished product requires not only the ability to handle a broad range of plastic and metal materials but also to achieve predictable results—particularly in the face of strict regulations.

These drill bits are made from durable cobalt-alloy high-speed steel, helping retain a sharp edge while drilling. They all fit inside the sturdy hinged case with a spring-loaded latch to keep the kit closed when not in use. The case also has a tap guide inside to help you identify which bit to use for a particular bolt or fastener.

Bits that drill through metal are further classified by the types of metal they puncture. For example, some bits are capable of drilling through ferrous metals, such as cast iron, and others through nonferrous metals, such as copper and tin.

For instance, Tsugami/Rem Sales’ LaserSwiss machine tool line was created for the medical industry. LaserSwiss combines traditional CNC Swiss turning and laser cutting in one machine, explained Tina Carnelli, marketing manager for Tsugami LaserSwiss. “This means medical manufacturers can produce complex medical parts, such as stents, with one setup and one part program,” she said. “We recently added a second laser head, for welding, to the LaserSwiss machine to effectively combine three operations on one machine.”

We tested these Top Picks products to ensure that they had what it takes for drilling metal. To qualify as one of the best drill bits for metal, the bit needed to perform well in the metal that it’s designed to drill. Bits also need to be durable and able to withstand the friction and heat produced when drilling through metal. The following recommendations are all at the top of their class for metal drilling, and one (or more) may be an asset to your tool collection.

“You might have 20,000 rpm on a milling machine, but if you’ve got a 0.01″ [0.254-mm] diameter drill, you will not get the speeds you need to run that properly,” he noted. “You may break the tool very easily.”

Most Swiss-style lathes use a gear train that runs three or four spindles simultaneously when the motor is turned on, Briggs said. With just one modular spindle with reduced gearing going faster than the rest, “you’re not taxing the other spindles. It’s nice to get higher spindle speeds for that fine surfacing and small five-axis work that the medical market is looking for more and more today.”

While we don’t have an immediate use for a dozen ¼-inch drill bits, we do like that a full-time shop can order enough bits from Drill Hulk to replace their most commonly used sizes without purchasing a whole kit that contains unneeded sizes. However, we did notice that these bits can walk slightly, despite the 135-degree split point.

Another innovation, low-frequency vibration (LFV) servo system technology “is one of biggest advances in the machining of tough materials used in medical component production,” said Jim Cepican, show manager for accessories sales with Marubeni Citizen-Cincom Inc. (Allendale, NJ). LFV improves tool life, chip control and processing of difficult-to-machine materials.

“Yes, it is about producing parts faster and holding tolerances,” said Patrick Loughney, product manager for small part machining, “but it’s also about the predictability of the process and tooling.”For instance, with turning inserts, “we changed our technology tremendously with our Inveio coating innovation,” he noted, which allows for stronger substrates, more precise edge treatment and a new way of applying coating.

Tsugami/Rem Sales is also developing quick-change turret holders for its turreted machines, in addition to its modular tool setups for face milling, angular milling and thread whirling attachments. “These holders are designed to help reduce operator error that could potentially lead to a machine crash or broken tools. This can also be done outside the machine on a Zoller or other presetting fixture.”

Add a drop or two of lubricating oil to the bit and then grab the broken end of its shank with a pair of pliers. Twist counterclockwise to remove the bit.

Whether outfitted on new machines or retrofitted on older machines, “our spindles do all the work,” Gabris said. Operators “have to lock the main spindle and run electric and air to our spindle, or just air if it is pneumatic,” Shea added. “The main spindle does not rotate, so there is no wear and tear on the machine spindle. Our spindles have no gears in them. By applying a small amount of air to them for cooling and purging, it is possible to run 24/7, with no thermal growth or harmonic issues. This is ideal in a constant high-production situation.”

At Marubeni Citizen-Cincom, “the introduction of laser cutting and welding on our machines is one of the most significant modifications we have made,” said Regional Sales Manager Rich Kuhn. “The ability to do machining work and laser cutting in the same machine has a major effect on reducing the number of operations required to produce a component. Adding automation and doing laser welding has allowed our medical customers additional choices for solving some of the ever-increasing high-tolerance requirements.”

To machine medical parts and features as small as the hexalobes in bone screws while preserving tool life, Tsugami/Rem Sales LLC (Windsor, CT) has equipped several machines in its portfolio with custom speed-quadrupling units.

It depends on what kind of metal you’re drilling through. Titanium bits are suitable for drilling through soft metals such as aluminum, while cobalt bits are better suited for drilling through hard metals like cast iron.

“We figured out that the crystals in the coating in the old process were random, to where they just protected the insert,” he explained. “Now we are able to align those crystals in one direction to where we can provide better tool life and insert wear.” This allows fewer adjustments to the machine and offers the predictable tool life critical to a stable machining process. After the insert is molded, edge preparation is executed to micron tolerances, he said.

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The Bosch bits’ tapered tips can quickly penetrate the metal, balance the bit, and produce a clean, even hole. The set includes 21 bits ranging in size from 1/16 inch to ½ inch and is packaged in a plastic storage case.

These bits are made for hard use. Their construction is durable, retaining an edge while drilling through thick ¼-inch steel. The no-spin shank prevented the chuck from slipping, boring right through the metal without stopping. They also stayed cool while drilling.

Most drill bits are made from HHS, cobalt, or carbide. A bit’s material can influence how effective it is at drilling through different kinds of metals.

When an NSK spindle leaves the factory, it is guaranteed to have less than 1 μm of runout, Gabris said. NSK also manufactures its own precision collets, accurate to three to five microns, and offers costly-to-manufacture ceramic bearings on all high-speed spindles.

Glenda Taylor is a BobVila.com staff writer with a background in the residential remodeling, home building, and home improvement industries. She started writing for BobVila.com in 2016 and covers a range of topics, including construction methods, code compliance, tool use, and the latest news in the housing and real estate industries.

On request, Rem Sales will integrate Tsugami Swiss machines with FANUC robotics for loading and unloading parts, Keyence vision systems for in-process gaging and auto compensation for automating offset adjustments on the fly, Briggs said. “We’re pulling a part off the conveyor from the machine with a robot, orienting it and placing it into a fixture on the measuring device. If any measured dimensions are out of tolerance, the Caron Engineering AutoComp system will automatically compensate in the machine as it is running, and the robot will place the bad part in a separate bin to ensure no bad parts are mixed with good.”

Folks who need to drill a few holes in some metal surfaces but don’t want to break the bank on a set of expensive drill bits may prefer the DeWalt DWA1184 black and gold drill bit set. This set of all-purpose bits can drill wood, plastic, or metal and features 135-degree split-point tips to help prevent walking.

These bits are made from high-speed steel for strength, and they feature a titanium coating for reducing friction and increasing durability. The kit comes with a carrying case with a foam insert with recesses for each bit and a spring-loaded center punch for marking the holes’ locations.

To be 100 percent upfront, we have never liked DeWalt drill bits. We have found that they’re usually relatively low quality and pretty much “throwaways.” But this particular kit was incredible when it came to drilling metal. They didn’t walk at all, and they cut long, continuous, spiraled shavings—the sign of a sharp bit. The rounded shanks on the smaller bits did spin a little, but the no-spin shanks on the larger bits were great. Each bit stayed cool with a spritz of lubricant and remained sharp throughout the test. And, surprisingly, this budget kit drills through wood faster than some of the much more expensive drill bits in the test.

While a standard thread whirling attachment will certainly do the job, if a machine is dedicated solely to producing bone screws all day, manufacturers should consider requesting ceramic bearings instead of more standard steel roller bearings. With ceramic bearings, operators can tighten the preload more than on steel, stiffening the system and maintaining maximum spindle speeds. Ceramic bearings dampen very fine harmonics and vibration when cutting bone screws and can also take the heat of higher rpms, dispersing heat much better.

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In fact, 0.005″ (0.127 mm) is becoming a standard diameter for solid-carbide end mills and drills, added NSK Product Manager Mike Shea. “If you want to run 200 sfm, that’s about 76,000 rpm if you’re running it correctly,” he explained. “Even if the [tool] manufacturer recommends running 100 sfm, you’re still just under 40,000 rpm. Our spindles fit the need for machining the micro and nano applications that are becoming much more common.”

These are great bits, but we found they were better for enlarging holes than actually drilling them (at least when it comes to metal). If we started with another bit to drill the initial hole, we could quickly work up to the desired size with the Comoware (the tips of the bits themselves just didn’t seem sharp enough for metal). We liked that there are so many sizes in one kit, and the spring-loaded center punch worked well for locating the bit.

With medical components usually produced in batches with frequent changeovers, accountability and traceability are paramount, he continued. “It’s a little bit harder to automate something like that. But it is changing; the systems and software are improving to where it can be tracked better.”Regarding another trend, the continued push toward Industry 4.0, machine builders are responding with numerous innovations.

Sandvik Coromant’s biggest hurdle, however, is thread-whirling inserts. “The majority of the time, a bone screw has a special thread form,” Loughney noted. “It seems that every doctor who has come out with a bone screw has his own signature thread form. So we can’t sell just standard inserts for that; they all have to be specially engineered. We have to be really flexible in grinding these inserts on a case-by-case basis.”

It’s not a bad idea to clean drill bits after using them. After drilling, wipe away any residue on the bit with a soft cloth and then rub a bit of cutting fluid on it before storing it.

For today’s customers, “we cannot simply provide a single machine to process parts,” explained MCC’s Cepican. “We have to provide complete processing systems. This includes highly technical automation systems.” MCC has designed several automatic loading and unloading systems—for instance, systems that load blank parts into machines to be laser welded to a component that has been machined.

Whether you’re just getting into metalwork or you want to expand that drill bit set, adding metal drilling bits to an arsenal of tools is a good investment. If drilling through metal is a new endeavor, there may be some questions that need answering.

Look for the words “metal drilling bit” on the package, followed by a list of metals the bit is designed to puncture. Here are a few additional tips that will help drill smoother holes and keep bits in tip-top shape.

Conversely, if using just a geared speeder head, the speeder should rest after 20 or 30 minutes of use to dissipate the heat in the gears, he advised.

MCC’s L series machines “are used by the majority of medical manufacturers we work with” for their faster processing speeds and enhanced programming capabilities, Cepican noted. “The number of axes has increased, including a B axis that is necessary for manufacturing more complex medical components.”

Drill bit coatings affect how a drill bit operates. Most metal drill bits are usually coated with titanium or black oxide. This coating is designed to reduce friction, which keeps the drill bit from heating up and eventually breaking. Because the coating reduces friction, it can also help increase drill speed.

Sandvik Coromant has also created special turning inserts for medical plastics like polyether ether ketone. “Most of the inserts are blasted on top so the plastic doesn’t stick,” Loughney explained.In October, a new drill made especially for heat-resistant materials in medical and aerospace applications will be part of the company’s biannual new product releases.

The L12 is a particularly good seller for the medical market, added Regional Sales Manager Glen Crews. “The machine’s small size and high spindle speeds make it ideal for machining miniature medical device components. Options are also available on all our machines to reduce the spindle size, making material handling easier.”

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When Tsugami/Rem Sales needed to create a high-frequency eye tumor removal device, the specs were challenging: the unit had to be 5″ (127 mm) long with a 0.06″ (1.52 mm) hole drilled all the way through. It employed the high-frequency pulsating TriboMAM system from M4 Sciences to do the job.

Tsugami’s solution is an attachment using gear reduction that multiplies spindle speed by up to four times without taxing the spindle motor to reach an optimal speed, such as 20,000 rpm. Tsugami/Rem Sales can even integrate the high-speed spindles made by NSK America and run them up to 80,000 rpm.

Ultimately, using the proper standalone electric or pneumatically driven spindles is vital to optimizing feeds and speeds for today’s medical applications, said Michael Gabris, industrial sales manager at NSK America Corp. (Hoffman Estates, IL).

First, we drilled into some relatively light-duty 11-gauge steel angle iron, testing a few bits from each pack. We wanted to see how well they’d retain their edge, how hot they’d get, and how long it would take them to bore a hole in the metal.

Additive manufacturing, or 3D printing, has afforded numerous opportunities for Trumpf, she added. “The building of various dental crowns, bridges and RPDs using our TruPrint 1000 enables manufacturers’ generative production of the smallest single-batch parts and series on the plate. With a multilaser option, production can increase up to 80% while still maintaining flexibility to process customer orders. Even complex shapes can be quickly and easily converted from the CAD design to a 3D metallic component with top quality.”

One of the best features of the Irwin 29-piece set is the range of sizes available. Each bit increases by 1/64-inch increments between 1/16 and ½ inch, meaning there is a bit for almost any size hole.

Avid metalworkers looking for a quality drill bit set for their metal projects may want to upgrade to the Irwin 29-Piece cobalt-alloy steel drill bits set. This set includes 29 drill bits from a 1/16-inch bit to a ½-inch bit, with bits larger than ⅜-inch wide having reduced-size shanks so they can fit smaller chucks.

Whether it’s just turning and milling or hybrid processes with lasers being teamed with Swiss systems to perform cutting and welding operations all in one machine, medical manufacturing requires machine builders and toolmakers to stay on their toes.

Meanwhile, the CoroMill 316 exchangeable-head milling system has been modified with extended cutting depth, especially for producing the knee trays that support implants.

Most drill bits fit both standard corded and cordless drills. While these small pieces of metal all look pretty similar, each type of drill bit is designed to make holes in specific materials—including wood, plastic, and metal—but won’t work as well on other materials.

Standard spindles on Swiss-style machines typically spin live tools at 6000 to 8000 rpm, said Derek Briggs, Swiss product manager for Tsugami/Rem Sales. “When you are performing fine surfacing and five-axis contouring, engraving or etching, you need extremely high rpms because the tools are very small; you typically have an 0.125″ [3.175 mm] or smaller ball end mill that you are doing fine contouring with, and you’re cutting on center during these types of operations. You need very high spindle speeds to keep the surface footage at an acceptable level for tool life and meet surface finish requirements.”

Strict regulations governing every aspect of medical component production and the need to ensure a stable, predictable process would seem to make it ideal for automation. However, that rigid oversight presents a conundrum, according to Sandvik Coromant’s Loughney. Once a process is settled upon, it can be extremely difficult and too time- or cost-ineffective to change—even with a material or process innovation waiting in the wings.

Many DIYers don’t bother sharpening their bits when the cutting edges become dull and they have trouble drilling a hole, but it’s tool maintenance worth doing. You’ll get a longer life out of your drill bits if you sharpen their cutting edges with a bench grinder.

While we’re not huge fans of general-purpose bits typically, especially when it comes to drilling metal, these Bosch bits were excellent. They didn’t walk when starting a hole, and they removed long shavings of metal, proving they remained sharp while drilling. We were so shocked that these bits were this good that we kept drilling with them to see if it was a fluke. They drilled holes faster than the other bits in the test, which really surprised us.

It is that design flexibility that can set lasers apart from traditional machining when it comes to metal-based, layer-by-layer powder bed production.

DIYers and pros who go through a lot of ¼-inch drill bits for their heavy-duty metalworking projects may benefit from the Drill Hulk’s ¼-inch cobalt steel set. This 12-pack of bits features jobber-style lengths, which means their lengths are relatively long compared to their diameters. They’re made from durable cobalt high-speed steel, feature 135-degree split points for drilling through metal without walking, and have a no-spin shank to prevent them from spinning in the chuck.

Researching shank design, bit material, and bit coatings can be confusing, but fortunately, drill-bit manufacturers make shopping relatively easy for the customer. Drill bits are labeled not only by the size of the hole they’ll drill but also by the type of materials they’ll drill.

There’s only one good way to test drill bits for metal: We needed to put some holes in some metal! We grabbed some scraps of metal off our welding cart, chucked some bits into our drill, and started drilling.

The best way to drill through thick metals is to use a drill press rather than a handheld drill—a press best achieves a clean, smooth hole. Be sure to drill slowly and use cutting fluid to lubricate the bit, too. Let the bit cool down every few minutes to keep it from overheating and breaking.

This kit comes with 14 bits from 1/16 inch to ½ inch, all of which are made of high-speed steel. The smaller bits have rounded shanks while the larger bits have no-spin shanks. Each bit features the brand’s “black and gold” coating designed to keep them from rusting. Everything stores away in a see-through case, helping to keep the bits organized and easy to find.

Home improvement centers often dedicate an entire aisle to drill bits, which come in a plethora of types and sizes for drilling holes in a variety of materials. Many drill bits can pierce through more than one type of material, but not all drill bits can drill through metal without heating up and snapping in half. Labels on drill bits indicate the type of material for which they’re suited, so it’s easy enough to find ones that are designed to drill metal. Depending on the type of metal the user is drilling through, some bits suit the task better than others.

In addition to maximizing spindle speeds, Tsugami/Rem Sales is also working to introduce more quick-change functionality to Swiss machining. The company offers live-tool attachments and gang tool plates with removable heads that let an operator take out a screw, remove the entire ER collet assembly or tool cartridge, set tool height outside the machine and install a pre-prepared spare—all in 30 seconds, Briggs noted.

The device, made of a custom titanium, is akin to a vacuum and can suck out just the tumor, not other soft tissue, Briggs explained. Typically, a gun drill would only be able to be fed at less than one-tenth of an inch per revolution; integrating TriboMAM quadruples that speed “because the oscillation of that tool breaks chips into very small pieces, and high-pressure coolant is extracting them out of the hole.” In all, a process that would otherwise have taken several minutes was completed 75% faster.

When traditional machining alone will not fill the bill, adding one or more lasers to the process greatly enhances manufacturing capability.

The shank is the nondrilling end of the bit that fits into the drill’s mandrel or “chuck.” For hex shank bits, the shank size of the bit chosen (typically ¼ inch, ⅜ inch, or ½ inch wide) should match the chuck size of the drill.

“By harnessing the techniques for design with 3D printing, a manufacturer or lab can build a product to near net shape,” Quaranta said. “There is very little scrap as seen with traditional machining, and the metallurgy is sound. Manufacturers can leverage these platforms to build a variety of components from implants and dental crowns to scaffolds and constructs for many applications.”

“We have modified our tooling to execute different medical features,” he continued. “We have our medical boring bar especially made for producing the cuff for knees and hip joints.”

Tom Scalisi has been in the trades for over two decades. He loves to share his knowledge of construction, home improvement, tools, techniques, and products with the readers of Bob Vila, This Old House, Family Handyman, and even his pest control blog.

When looking for a set of high-quality drill bits for metal, you may want to consider the Irwin 63137 set of bits. Made from cobalt high-speed steel, they’re designed specifically for hardened steel. They have 135-degree split-point tips, helping them to resist walking when starting a hole. They also resist wear and heat, making them a solid choice for drilling through metal materials. Bit sizes range from 1/16 to ½ inch wide, and the bits larger than ⅜ inch wide have reduced shanks.

These bits did a fine job of drilling through our test materials. They didn’t walk when we started the holes, and they bored through the metal at a reasonable pace. The case itself has a cheap plastic tab to keep it shut, but otherwise, it does a good job of keeping these bits safe and organized. They stayed cool while drilling and retained their sharp edges even after several holes. Our biggest complaint is the rounded shank, as the small bits did spin a bit in the chuck.

Some shank designs are more conducive to drilling through metal than others. Most shanks for this type of drill bit are either no spin or hex.

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The bits didn’t cut quite as fast as some of the other drill bits in the test, but they did retain their edge nicely. They also didn’t walk at all when starting the bit, and the tap size chart inside the kit could definitely come in handy. What we didn’t like was the fact that every bit, despite its size, features a rounded shank. But the sturdy case with a spring-loaded latch ensures this kit stays shut, and the rubber molding on the case can prevent it from slipping off of a work surface.

“We are seeing more automation in medical manufacturing, but the majority is on the secondary operations that are not controlled as much, like grinding a gate off a forging,” he said. “We are seeing newer things like hip stems being produced with automation.”

Of course, lasers have been a standalone medical manufacturing solution for some time. For instance, Trumpf’s portfolio is widely used by medical device manufacturers, from laser welding and fine cutting applications to additive manufacturing and laser marking for traceability, according to Salay Quaranta, industry manager for Trumpf Inc. (Farmington, CT).

When it comes to machining today’s finely tuned medical components, speed—not to mention tool life and automation—is of the essence.

When it comes to enlarging hotels in metal materials, a step bit like the ones in this five-piece kit from Comoware is the tool for the job. This kit features five different sets of bits, each with a series of steps, totaling 50 sizes from one kit. Sizes range from ⅛-inch to 1 ⅜-inch wide.

We did dislike that the smaller bits have rounded shanks, as they can be a pain, particularly when the bit is about to drill all the way through the material. However, the large bits have no-spin shanks and do a great job of staying in place. The tips stayed sharp making hole after hole, and they remained cool to the touch during use (while using cutting oil).

With medical component materials ranging from plastics to cobalt chrome to titanium, Sandvik Coromant (Fair Lawn, NJ) has evolved its tooling considerably over the past few years.

Faster spindles have been developed for cross working and end drilling that are interchangeable with the machine’s standard spindles, Crews added. “Being gear driven, they are able to attain high spindle speeds with better torque than you would get with the electric or air-driven spindles many manufacturers use.”

Through hands-on testing, we found a number of drill bit sets that rise above the competition and help make holes in myriad metals. Some of the results were truly surprising. For those of you working on a project that requires drilling through metal, read on to learn about the factors to consider before shopping for the best drill bits for metal.