Turning small parts is nothing new for many machine shops. Industries like automotive, aerospace, electronics, firearms, and medical are pushing the envelope when it comes to small-part production. Typically, any application requiring a workpiece smaller than 1 in. dia. is considered small-part turning.

Looking for tooling that is purposely designed for small-part turning or microturning is a good place to start. These tools tend to have tighter tolerances and are more finely ground.

Image

Image

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.

Because of the low cutting speed required, built-up edge can be a problem. On larger parts burrs can be removed easily with the secondary processes, but it’s more difficult with small parts.

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!

For shops looking to take on small-part turning operations, there are a number of things that can be done to ensure success.

Articles may contain affiliate links which enable us to share in the revenue of any purchases made. Registration on or use of this site constitutes acceptance of our Terms of Service.

"Automation for small parts has historically been a challenge, but we are really starting to see some new and exciting advancements in automation," said Mara.

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 No. 1 thing to consider is chip control," said Easterday. "Having the correct chipbreaker is key. The chip needs to be directed away from the workpiece."

We may earn revenue from the products available on this page and participate in affiliate programs. Learn More ›

"Because of this, the process needs to be planned to minimize tool pressure using sharp, positive tools," said Edwin Tonne, training and technical specialist, Horn USA Inc., Franklin, Tenn. "It’s important to look for well-defined cutting edges and a positive top rake. Fully sintered cutting tools can be problematic because they’re just not sharp enough to minimize the pressure. Look for finely ground cutting edges with plenty of clearance. A sharp wedge angle will help prevent deformation in the part. Form tools are a good choice because they can simplify the process."

"One big mistake is not checking the alignment of the machine," said Tonne. "Alignment is everything."

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.

"Everyone wants to automate their process," said Mara. "We can’t get skilled people, so the logical step is to automate. End-of-arm tooling is not typically as dextrous as it needs to be for small parts, and robot accuracy may not be sufficient. It’s difficult to hold very small parts with a robot, especially for loading and unloading."

Depending on the size of the parts and specifications needed, small-part turning can be done on a conventional CNC.

Luminoso has a bachelor of arts from Carleton University, a bachelor of education from Ottawa University, and a graduate certificate in book, magazine, and digital publishing from Centennial College.

Another area of importance is measurement and inspection. Small components require different inspection methods than their larger counterparts, especially because of the microtolerances and tiny features.

A conventional CNC lathe is good for general-purpose turning but usually has spindle speeds of only about 3,000 to 5,000 RPM, whereas a Swiss-style lathe can be in the 10,000- to 15,000-RPM spindle range. That higher RPM enables the machine to generate the surface speed needed to cut small-diameter parts efficiently.

"Sharp molded and ground cutting tool inserts provide less tool pressure and freer cutting," said Steve Easterday, Swiss applications engineer, Kyocera Precision Tools, Hendersonville, N.C. "Physical vapour deposition (PVD)-coated inserts provide excellent tool life and a sharper edge."

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.

"Common mistakes can include incorrect cutting conditions like incorrect surface footage, too high feed rate, and too heavy depth of cut, which can result in incorrect tolerances that include part bending and poor finish," said Easterday.

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.

With small tools, a high-quality modular system, like Horn’s W&F Micro precision modular tooling, will allow operators to keep a close eye on the tool wear. Horn

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.

"The screw could be an M2.5 or smaller, and in some cases, they can be easily lost to the bottom of the machine or conveyor system," said Tonne. "The other thing I would recommend is using torque-limiting drivers at all times. If you overtorque an M2.5 screw, you’re going to strip it, and that will add a lot of extra time getting that screw out and changing the insert."

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.

Another concern with small parts is they get washed away with chips. For example, part ejectors that put small parts into the conveyor may have issues separating them from chips. A vacuum that removes the part when the chuck opens and puts it in a separator is a good option.

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.

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.

On a conventional lathe you may be able to turn a length-to-diameter (L:D) ratio of about 10:1, and that is only if the machine has a steady rest or similar supporting device. On a Swiss-style machine, the L:D can be as much as 20:1, making it possible to produce very difficult parts.

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.

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.

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.

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.

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.

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.

Another thing to consider is keeping plenty of extra hardware for the holder around because typically the screws holding the insert tend to be very tiny.

Lindsay Luminoso, sr. editor/digital editor, contributes to both Canadian Metalworking and Canadian Fabricating & Welding. She worked as an associate editor/web editor, at Canadian Metalworking from 2014-2016 and was most recently an associate editor at Design Engineering.

Automation is slowly making its way into all aspects of the shop floor. However, when working with small parts, automation may not be the obvious next step.

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.

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.

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.

With very tight tolerances, it can be challenging to get the tool back to size after indexing. Monitoring and controlling the size after indexing the cutting tool is a must for small-part turning.

"You may want to think about using a vision inspection system, offline gauges, and those sorts of devices," said Tonne. "These take more time than using a caliper or bench-type measurement tool. Getting the part to the right size and back up and running after tool indexing is also critical."

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.

The enemy of precision machining is vibration and heat. Rather than heavy, deep cuts, small, higher-speed cuts can keep the workpiece as cool as possible, reducing heat deformation in the part. Any sort of deformation can make it difficult to maintain proper tolerances. According to Mara, Swiss machines usually use high pressure up to 2,000 PSI with water-based coolant to help keep the heat out of the part.

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.

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.

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.

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.

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.

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.

"With small tools, a high-quality modular system will allow you to keep a close eye on the tool wear," said Tonne. "If you have a feature that’s only 0.001 in. deep, and you lose the radius of your tool, you can have a problem on your dimensional tolerance, so keeping a close eye on the tool is very important."

"For shops looking at turning long and thin parts, a conventional CNC lathe has its limitations and probably wouldn’t perform as needed," said Mara. "A Swiss-style machine offers the rigidity in the setup required to turn very small or long parts by doing the cutting as close as possible to the spindle nose and by feeding the material through a stationary tool as opposed to the tool moving across the part as on a conventional lathe. Choosing a Swiss-style machine is definitely the best option, if possible, for turning long, thin parts."

Image

Tonne agreed that when working with long parts, pinch turning is a great option. Pinch turning helps keep everything aligned. The external features are completed first to maintain that stability and then internal operations are performed.

A machine needs to have a rigid setup, regardless of whether it’s a conventional or Swiss machine, and it is vitally important that the correct tooling be used for small-part turning. EMEC

"Many of today’s new machines come equipped to handle smaller parts," said Bill Mara, president, EMEC Machine Tools Inc., Mississauga, Ont. "One of the biggest challenges machine shops face when dealing with small-part turning is the machine’s capability to hold the parts effectively without damaging or distorting them, but that’s not really a problem anymore. For shops looking to get into parts that are smaller than 0.250 in. dia., a Swiss-style lathe is the way to go."

We’re committed to testing and reviewing products so you can make an informed decision. Advertising does not influence our product reviews and it never will. We always focus our coverage on standout products and never hesitate to mention their flaws and quirks. By using our affiliate links, you’re supporting our work and helping us continue to provide expert analysis. Find out more about our product evaluation process.

Chip control and evacuation can be cumbersome in small-part turning. For the most part, the biggest tool possible is the better option, but it’s important to remember that there must be enough room, especially in boring operations, for chip evacuation. High-pressure coolant can be a huge help with this.

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.

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.

Easily access valuable industry resources now with full access to the digital edition of Canadian Metalworking.

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.

"Shops have been cutting small parts forever and have found innovative ways to do it effectively," said Mara. "It’s important to remember that a machine needs to have a rigid setup, regardless of whether it’s a conventional or Swiss machine, and it is vitally important that the correct tooling is used."

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.

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.

"If their machine is equipped with HP coolant pumps, internal coolant through tooling is a must," added Easterday. "Make sure that the workpiece can be done on the machine you have. In many cases when you are dealing with long workpieces, adjustments need to be made. Extended guide nose bushings or the capability to pinch-turn can be helpful."

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.

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.

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).

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.

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.

With a long part it’s always a good idea, especially with a small diameter, to try to grab it with the secondary spindle. While this may add a little bit of time, gripping and not letting the part hang out adds the stability needed to ensure tolerances are met.

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.

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.

Micromachining, on the other hand, is classified by part diameters that are too small to be fixtured using a standard collet. In some instances, this could mean parts that are 0.1 in. to 0.02 in. dia. all the way down to the size of a human hair, depending on the equipment.

Easily access valuable industry resources now with full access to the digital edition of Canadian Fabricating & Welding.

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.

Chip control is essential for effective small-part turning where the chip needs to be directed away from the workpiece. Kyocera Precision Tools

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.

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.

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.

Swiss-style CNC machines even can perform other operations like this tapping of a small-diameter brass shaft. Phuchit/iStock/Getty Images Plus

With small components, tool pressure is a primary concern. Very small parts can easily deform during turning operations.

"When working with anything less than 0.250 in. dia., it becomes difficult to reach the correct speed for normal steel material," said Tonne. "And with RPM limitations on the machine, sharp cutting edges and very lubricious coatings are helpful. When it comes to depth to cut, typically the machine will perform a single finish pass. This needs to be balanced with tool pressure. First and foremost, keep your feeds very modest. Form tools and special tooling can help claw back some of the time."

Operators need to be mindful of the cutting edge at all times. It needs to be sharp, and damage can occur very easily from general wear, handling, or even indexing.