Please note, these are our test results from internal testing. We recorded a video of each hole being drilled. These videos are available on request for your test accuracy verification purposes.

To find out what are the best metal drill bits, we tested the best products from the biggest brands. In our tests, Adiseal Ultimate cobalt metal drill bit has been shown to be the best metal drill bit available. It has proven to be the most durable and fastest drill bit in our tests, beating the biggest brands.

We carried out the test by using a Scheppach DP60 drill press. The test was to drill as many 10mm holes as possible in 6mm thick stainless steel (SUS304) with each drill bit being tested. We set the drill press at a consistent 400 rpm speed for all of the holes drilled by all of the products tested.

What is a relief cutwoodworking

Examine the drilled hole for smoothness and accuracy. If needed, you can use a deburring tool to remove any rough edges.

Use a center punch or awl to create a small indentation at the desired drilling point to prevent the drill bit from wandering and ensure a precise start. However, with certain bits like Adiseal Ultimate, this step may be unnecessary.

Question On mouldings with a profile, base, cases, etc, what is the best way for the back side relief profile? Many half moon cuts, one big relief cut, two, or many small slots? Forum Responses (Solid Wood Machining Forum) From contributor D: The main reason for relieved backs on such moldings is to ensure that the visible edges of the moldings stay tight against the surface they're nailed to, even if the molding cups outward a bit. Any method that leaves parts of the molding towards the middle untouched (i.e. slots, half moon cuts, etc.) won't achieve this. You're looking for a wide, shallow recess. From contributor J: I have never used more than one relief on the back of a moulding. I usually go about 1/16" to 3/32" deep +/- for personal/customer preference, and about 2/3 the width of the moulding. It is usually centered unless the customer has specific nailing preferences. 45 degree angles on both sides of the cut to prevent tearing of the wood fiber. Many small cuts help to take up some of the swelling in wide pieces of flooring, but most mouldings don't experience this issue, they are simply not wide enough. Bottom line is to find a technique that works for you and keeps the customer happy. From contributor J: The most efficient way to make a relief head is to use a six inch head, four knife, most profiles are not over six inches. If it is, use the same technique below, but with a bigger head. Use the first two pockets for straight knives, leave them there all the time, just touch them up now and again. The second two pockets use to change out three sets of relief cutters. I say three sets because I have always used three sets, different widths, this technique works for just about everything. The straight knives produce the finish on the bottom face, the relief cutters should be set 1/16" to 3/32" higher than the straight knives to leave the proper relief. It would be nice to make individual sets for different profiles with just two knives, but no one I know does it, too costly.

Concreterelief cutsaw

Adiseal Ultimate has been shown to be the fastest and most durable metal drill bit in a test drilling into stainless steel. It drilled faster and drilled drilled more holes than any other cobalt drill bit.

In reality, additional savings come from prolonged tool lifespan, reduced energy consumption per hole, and fewer trips to buy replacement bits.

To compare costs, let’s consider drilling 10 holes in 6mm stainless steel with the Adiseal Ultimate and Bosch cobalt drill bits.

Relief cutmachining

As you continue drilling, maintain a steady, even pressure on the drill. Avoid pushing too hard, as the drill bit’s cutting edges should do the work.

HSS (high-speed steel) and Cobalt drill bits can be sharpened using a drill bit sharpener or bench grinder. Carbide and diamond-coated drill bits are more difficult to sharpen and may necessitate professional service.

Adding these labour costs to the drilling costs above, total cost to drill 10 holes is:Adiseal Ultimate: £2.53Bosch cobalt: £12.90

It’s important to note that some non-cobalt drill bits like HSS bits (high speed steel), including Milwaukee Thunderweb and Bosch PointTeq, were also tested but not included in the chart to maintain fairness (Bosch PointTeq was unable to drill any holes at all in the 6mm thick stainless steel SUS304).

Whenisit too late tocutconcrete

Faster drilling extends tool lifespan by reducing usage. Slow-drilling bits increase runtime, potentially causing quicker wear. Longer-lasting tools can offer additional cost savings.

Also be careful when touching the removed chips as they can be very sharp and can cut easily. It is advisable to wear gloves if you need to handle them.

Adiseal Ultimate drilled 9 times the number of holes than the best cobalt bit from Bosch & over 3 times the number of holes than the best cobalt bit from DeWalt.

In their attempt to make available the best drill bits, also added to the Adiseal Ultimate drill bits range is the fastest no hammer masonry drill bit & multi material drill bit. It can drill faster than any other drill bit when drilling without hammer function on the drill. This gives it numerous advantages over hammer drills. It will drill into brick, drill concrete, wood and many other building materials. This carbide bit has been shown to be the best masonry drill bit with a hex shank.

In the UK to buy drill bit for metal, please contact us for details of your local stockist. For other countries, please visit www.guglue.com

As well as drilling more holes than any other metal drill bit, Adiseal Ultimate also drills faster than any other bit. In the same test as above, we also measured the time it took to drill each hole. We did this for the first 10 holes and recorded the average.

What is a relief cutwood

Forum Responses (Solid Wood Machining Forum) From contributor D: The main reason for relieved backs on such moldings is to ensure that the visible edges of the moldings stay tight against the surface they're nailed to, even if the molding cups outward a bit. Any method that leaves parts of the molding towards the middle untouched (i.e. slots, half moon cuts, etc.) won't achieve this. You're looking for a wide, shallow recess. From contributor J: I have never used more than one relief on the back of a moulding. I usually go about 1/16" to 3/32" deep +/- for personal/customer preference, and about 2/3 the width of the moulding. It is usually centered unless the customer has specific nailing preferences. 45 degree angles on both sides of the cut to prevent tearing of the wood fiber. Many small cuts help to take up some of the swelling in wide pieces of flooring, but most mouldings don't experience this issue, they are simply not wide enough. Bottom line is to find a technique that works for you and keeps the customer happy. From contributor J: The most efficient way to make a relief head is to use a six inch head, four knife, most profiles are not over six inches. If it is, use the same technique below, but with a bigger head. Use the first two pockets for straight knives, leave them there all the time, just touch them up now and again. The second two pockets use to change out three sets of relief cutters. I say three sets because I have always used three sets, different widths, this technique works for just about everything. The straight knives produce the finish on the bottom face, the relief cutters should be set 1/16" to 3/32" higher than the straight knives to leave the proper relief. It would be nice to make individual sets for different profiles with just two knives, but no one I know does it, too costly.

Point angles impact drilling efficiency and suitability for specific metals. Common angles include 118 degrees for general-purpose drilling and 135 degrees for harder materials. Smaller angles like 90 degrees are ideal for countersinking.

Select drill bits based on metal hardness. HSS bits (high-speed steel) are suitable for softer metals like aluminum, brass, and copper. For harder metals such as stainless steel and high-carbon steel, Cobalt or Carbide bits are recommended.

Exercise caution when handling the drilled material or the drill bit immediately afterward, as they can still be very hot. Hot metal can cause burns, so either allow them to cool before touching with bare hands or use appropriate heat-proof gloves.

Continue drilling until you’ve reached the desired depth. Slow down as you approach the end to prevent breakthrough damage.

To highlight potential labour cost savings, consider the time and effort required to drill 10 holes in 6mm stainless steel using the Adiseal Ultimate and Bosch cobalt bits.

We used the best 10mm metal cobalt drill bits from reputable brands like Milwaukee Cobalt Red, DeWalt Extreme, Bosch Cobalt, and Makita. To ensure consistency, a 5kg weight was suspended on the drill press arm during each hole’s drilling, maintaining uniform force and RPM. to test the wear resistance and durability, we tested without using lubricants, coolants, or cutting oils, although these can help reduce the drill bit’s temperature and extend its lifespan.

Adiseal Ultimate 10mm metal drill bit price: £10.14Cost per hole (£10.14 / 135 holes): £0.076666Cost to drill 10 holes: £0.77

The drilling of each hole were video recorded and timed via video timestamps. Following the tests, the Adiseal Ultimate metal drill bit proved to be the best metal drill bit available, excelling in both being the most durable and fastest drill bit for metal to drill each hole.

Reliefcuts in concrete

Adjust your drill speed to match the metal you’re drilling; slower speeds work well for harder metals to prevent overheating and extend the bit’s life. Ensure the drill rotates in the correct direction, usually clockwise for most drill bits.

Suhail Matadar has extensive experience in the construction industry as an electrician, involved in installing, inspecting, and testing electrical systems in various projects. He excelled in sales, working for a major UK wholesaler, selling construction products to professionals and the DIY market. Suhail's background includes working at a leading home emergency repair company dealing with trades people. With a BEng (Hons) degree in Electronic Engineering, Suhail has worked with PLCs in the nuclear fuel manufacturing industry. During his studies, he gained practical experience at a chemical manufacturing company known for producing award-winning cleaning, hygiene, and livestock protection products for over a century. Currently, Suhail runs a global business specialising in supplying, researching, testing, and distributing chemical construction products like adhesives and sealants.

The main types of drill bits for metal are High-Speed Steel (HSS) drill bits, Cobalt drill bits, Carbide drill bits, and Diamond-Coated drill bits.

If you notice the drill bit heating up, pause occasionally to apply more cutting fluid or lubricant. This helps keep the drill bit cool and prevents it from dulling prematurely.

While some general-purpose drill bits may suffice for various types of metal, selecting a drill bit tailored to the specific hardness of the metal being drilled ensures optimal results.

The second two pockets use to change out three sets of relief cutters. I say three sets because I have always used three sets, different widths, this technique works for just about everything. The straight knives produce the finish on the bottom face, the relief cutters should be set 1/16" to 3/32" higher than the straight knives to leave the proper relief. It would be nice to make individual sets for different profiles with just two knives, but no one I know does it, too costly.

Adiseal Ultimate cobalt drill bits don’t require pilot holes thanks to their sharp cutting edge, preventing sliding and wandering. They also produce larger removed metal pieces, reducing the need to clear numerous small chips after drilling. It can also drill cleaner cut holes compared to other bits.

Relief cutmetal

What is a relief cutonabandsaw

For deeper holes, use the peck drilling technique. Drill a short distance, then pull the bit back to clear the chips. This prevents clogging and heat buildup.

To find out what is the best metal drill bit, we carried out endurance and drilling speed tests using a drill press with a weight hung on an arm of the drill press. Impressively, Adiseal Ultimate drilled more holes than the best bits from the top 3 worlds biggest brands combined. (Milwaukee cobalt red) 75 + (DeWalt Extreme cobalt) 39 + (Bosch cobalt) 15 = 129 holes, whereas Adiseal Ultimate drilled 135 holes on its own.

Hold the drill perpendicular to the metal surface. Place the drill bit’s tip into the center punch indentation and apply gentle pressure. Start drilling slowly to create a pilot hole.

Wear safety goggles to shield your eyes from metal shavings and consider using ear protection if noise levels are high. Work gloves can offer additional protection.

We tested the drill bits by drilling into hardened stainless steel. Adiseal Ultimate drill bits, drilled more holes than all the other products tested as well as drilling holes the fastest. In terms of durability and drilling speed, Adiseal Ultimate drill bits have proved in tests to be better than the best drill bits from big brands like Dewalt, Bosch, Milwaukee and Bosch.

Apply a suitable cutting fluid, coolant or lubricant to the drilling area. This helps reduce friction, heat, and prolongs the life of the drill bit.

As can be seen in the calculation above, it is over 7 times more expensive to drill each hole with the best metal cobalt drill bit from Bosch compared to Adiseal Ultimate metal cobalt drill bit. Based on cost per hole, Adiseal has more value for money.

Faster drilling reduces tool runtime, saving energy and additional money on top of other mentioned savings. Lower energy use to drill each hole also makes Adiseal Ultimate the most environmentally friendly metal drill bit.

A faster-drilling drill bit not only saves on the cost per hole but also reduces labour costs. This is because less time is required to drill each hole, resulting in additional cost savings.

Cheap drill bits may cost more over time if they wear out quickly and drill fewer holes than durable ones. Calculate the cost per hole by dividing the bit’s price by the total holes drilled. Cheaper bits might have a higher cost per hole than more durable ones. In our test, Bosch PointTeQ’s non-cobalt bit failed to drill any holes, while the Adiseal Ultimate metal drill bit successfully drilled 135 holes in total.

Yes, cordless drills are suitable for metal drilling. Opt for a drill with adjustable speed settings and ample power to handle the metal you’re drilling. Ensure the battery is fully charged to maintain consistent performance.