Many are not aware, but you can calculate how much clearance to leave at the bottom and it’s probably more than you’d think.

These are special types of bits that can drill through plastic, tiles, glass, marble, and brick. They can also withstand high temperatures.

First, form taps can’t be used on hard materials. You can only form tap up to 36 HRC hardness materials. That’s a lot more materials than you’d think, but there’s definitely materials that can’t be form tapped. Second, some industries don’t allow form taps because the process can create voids that trap contaminants on the threads. Form Tapping can also create stress risers on the threads.

Be sure to check the requirements on the job—your customer may require a particular thread percentage. But if they don’t, or if it’s within the ranges in this chart, dial back the thread percentage and your taps will thank you.

Used to drill larger thru-holes in metal (7/16″ and up), these bits require a special machine. Similar to a hole saw, annular cutter bits cut the outer diameter of the hole and leave a solid center slug.

Note that spiral fluted taps are not as strong as the more common spiral point taps, which is why they’re not used all the time. Just use them on blind holes.

I just finished the 11th episode of CNC Chef for Cutting Tool Engineering. This video gives you 7 ways to avoid breaking taps:

The best drill bits for metal drilling in ascending order in terms of cost are High-Speed Steel (HSS) bits, Black Oxide bits, Cobalt steel bits, and Titanium bits. For drilling large holes in thin or soft metals, you can use a hole saw which can also be used with a cordless drill.

Here’s what’s key—a 100% thread is only 5% stronger than a 75% thread, but it requires 3 times the torque. So, for just a tiny bit stronger thread you wind up with a much greater chance of breaking your tap.  The chart on this slide shows the relationship:

Drill bits are cutting tools. If you do a lot of home projects or heavy-duty construction work, periodically sharpening your drill bits will be necessary.

Bob is responsible for the development and implementation of the popular G-Wizard CNC Software.  Bob is also the founder of CNCCookbook, the largest CNC-related blog on the Internet.

Also known as high-speed bits, they resemble corkscrews and are some of the most popular bits. They are typically used to drill small holes into wood and walls. Their unique design allows them to channel dust from the hole as they work.

Like auger bits, self-feed bits also feature a screw tip for positioning the bit. They create clean, precise holes, as well. However, since they do not channel the dust away from the hole as they work, you must halt the operation periodically to clear the dust away.

These bits come with carbide tips to allow you to bore holes into tiles without creating chips or cracks in the tile. Different tile bits are designed for different types of tiles. Therefore, ensure that you check its package to confirm that it can drill into your tiles.

Auger bits have a screw tip that creates the initial hole for the rest of the bit to fall. As a result, holes by auger bits are incredibly clean and precise.

This creates a much more efficient drilling process with burr-free holes in tubing, sheet metal, and iron bar stock. Annular cutter bits on our site are made from Cobalt High-Speed Steel.

These are what you use when looking to create holes in bricks, stones, or concrete. Due to the tough nature of those materials, masonry bits wear out quickly, meaning that you will need to replace them frequently.

The tip of the bit has a tiny hole where you insert the wire you are looking to pass through the material. Installer bits are incredibly long, reaching lengths of up to 18 inches to facilitate their work.

These bits have a special design that allows them to drill a hole into a material with the purpose of extracting its core.

Tin also provides the same benefits as black and bronze oxide. Tin-coated bits are suitable for drilling iron and steel as well as aluminum, magnesium, etc.

Drill bits made for steel, aluminum, copper, cast iron, sheet metal, fiberglass, brick, vinyl flooring, and more are also available.

Zachary Tong

As mentioned earlier, drilling through tile requires a specialist drill bit – regular or even masonry bits simply won’t do the job as they’re not strong enough to penetrate tiles’ hard surfaces. Instead, you should opt for either carbide-tipped or diamond-tipped drill bits.

Sized for their diameter, drill bits are constructed in a range of styles to help with specific tasks. Not sure which drill bit you need or what you need in your toolbox? Keep reading for a rundown of the different types of drill bits you’re likely to come across.

Drill bits are designed to drill holes in a variety of different common materials. These include different types of wood, metal, plastic, ceramic tile, porcelain, and concrete.

Named after their tip that resembles a series of pyramid-shaped steps, these bits are what professionals use to drill into sheet metal. Their stepped design allows you to create holes with varying diameters. Step bits are renowned for their versatility.

Breaking tapsyoutube

To start, use a holder that locks the square shank on a tap so it can’t twist in the holder. Tapping uses a lot of torque, so having a positive lock on that shank is helpful.

Each spot is marked for the bit’s size and type, making it easy to quickly find the right bit for the project you are completing.

The red-orange dots are tapping torque. Look how fast it climbs when thread percentage gets above 60%.  The blue dots are thread strength—it flattens out just when the torque starts climbing. The recommended drill size is almost always a 75% thread. Great strength, but well into that too much torque zone.

Every machinist hates breaking taps. It’s a real pain to extract a broken tap without damaging the part. Plus, tapping always seems to be one of the last operations done on a part, which just ensures the highest cost if you need to scrap the part.  But, there are 7 things I’m going to show you in this video that will great reduce the number of broken taps you have to deal with.

Brad-point bits come in handy when you need to make clean and precise holes. They come with rubber stoppers to allow you to set a particular depth. Their precision makes them a popular bit among woodworkers.

If your set didn’t come with a case or you’ve been buying individual drill bits, add a storage box with dividers to your toolset. Don’t store more than two bits together and use a permanent marker to mark each space with the size and type of drill bit stored there.

Crashing a CNC machine in a way that does costly damage is worse, certainly. But breaking a tap off in an expensive part that’s nearly finished has got to come in a close 2nd place.

Breaking Tapszach

Join 100,000+ CNC'ers!  Get our latest blog posts delivered straight to your email inbox once a week for free. Plus, we’ll give you access to some great CNC reference materials including:

Speaking of blind holes, my 7th and last tip is to mind the depth on blind holes. Crashing the tap into the bottom of the hole will almost certainly break it.

When it comes to drills, there are two easily identifiable parts you need to know about – the shank and the chuck. Here’s a little information to help you understand more about how drills and drill bits work:

The reason is the machine is limited by acceleration of spindle and axes on how closely it can synchronize the tap to the threads it’s making. There’s always some axial force pushing or pulling.  A floating holder will relieve stress from lack of perfect synchronization.

The chuck is the part of the drill that attaches the drill bit. Most power drills for home use have a 3/8-inch or 1/2-inch chuck. Larger chucks come in 5/8-inch and 3/4-inch sizes but are usually fitted on heavy-duty and industrial power drills and drill presses.

I walk you through the math below and you can see that for the example ¼-20 roll form tap we needed not quite a ¼ inch of clearance from where the tap stopped to the hole bottom.

Most drill bit sets are sold in a case with space to hold each bit in place. This keeps the drill bits from being nicked or scratched and also provides excellent organization.

Good video. I’m having problems tapping 4-40 blind holes in 6061-T6. Snapping the taps off so much I’ve switched to tapping by hand. Roll forms bulge the material out because it’s only .188 thick. Your tip about a Dip Cup is great, we would stop the machine and hand lube the taps. Never thought of a Dip Cup.

These are the bits to use when looking to drill into thick and dry wood. Thanks to their innovative design, you do not have to apply a lot of pressure when drilling into tough materials.

Drill bits make holes in a variety of different common materials. These include different types of wood, metal, plastic, ceramic tile, porcelain and concrete. Different types of drill bits made for steel, aluminum, copper, cast iron, sheet metal, fiberglass, brick, vinyl flooring and more are also available.

Most machine coolants, especially water soluble, are not as good for tapping. If you’re having problems, try using special tapping lubricant. Put it in a spill proof cut that sits on the machine table and program the g-code to dip the tap automatically in the cup.

Black Oxide: The most economical coating. Black oxide adds corrosion protection, increases tempering and stress relieving of the bit, reduces galling and chip welding, and aids in retaining drilling lubricants.

Bronze Oxide: Bronze oxide increases the tempering and stress relieving of the bit and is generally used alone to visually identify cobalt steel or with black oxide to identify better grades of high-speed steel.

The shank is the end of the drill bit that fits into the drill and is secured by the chuck. A round shank helps to center a bit in the chuck more accurately. The flat surfaces on a hex shank allow the chuck to grip the drill bit more securely.

Plug cutters are helpful in professional projects, as they drill holes into the wood while cutting the wood plugs you require to hide recessed fasteners.

Dull drill bits can increase time and effort needed to complete work and possibly damage the materials you’re working on, and may even cause injury.

As their name implies, these bits can be adjusted to create holes of varying sizes, thus eliminating the need for purchasing bits of different sizes.

These are what you use when looking to bore smooth and clean holes into the woods. This bit also comes with a pointed tip to allow for easy positioning of the bit.

Titanium Nitride (Tin): A more expensive coating that increases the hardness of the bit and provides a thermal barrier resulting in increased production rates and longer tool life in harder materials.

Black oxide is suitable for drilling iron and steel but is not recommended for drilling aluminum, magnesium, or similar materials.

Quarter-inch hex shank bits are intended to be used on 1/4-inch impact drivers and can be quickly changed. SDS (slotted drive system) shanks are used for concrete drills and demolition bits and work specifically with SDS-Plus and SDS-Max rotary hammer drills.

Breaking tapscnc

Spade bits have a spade-shaped tip that allows them to bore into softwoods. They are typically used to create holes for running cables.

It’s important to realize there is no one drill size for a tap. Different drill sizes result in different thread percentages.

Proper drill bit maintenance is not much different from maintenance for most tools, and it helps prolong the life of your drill bits and keeps them ready for the next job.

A sharpening tool can be a good investment to keep your drill bits in top shape. More experienced DIYers can accomplish the task with a good set of grinding tools.

Caring for your drill bits can also be a matter of safety; dull or damaged drill bits can create problems both in the work and for the worker.

You use a hammer bit to create precise holes into concrete slabs when looking to determine the amount of humidity in a concrete slab.