Archive for August, 2012

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How to Drill Metal

Drilling metal typically is not too difficult if you set up properly to do so.

Some would call it a very tricky operation. With a few precautions, you too can be an expert at drilling metal items.

The first thing to consider is, “What is it that I actually want to accomplish?” Drilling metal requires the right tooling – often simply called a “drill bit”, proper hole and location measurements and a good amount of patience during the set-up process. Do it right the first time because there’s always time to do it right the second time, eh?

Things we suggest you always have handy (and use!) might be:

  • Safety Glasses
  • A Hand Drill, Drill Press, Bridgeport or Similar Mill, etc.
  • Tooling or “Drill Bits”
  • Cutting or Drilling Coolant / Fluid
  • Information – See the following CHART for some idea of the speed you should be running (RPM) when using HSS (High Speed Steel) tooling

Basic Drilling Guidelines or Instructions

    1. Always secure the piece that you want to drill. Use a proper vise or a clamp so it can not slip, spin, lift up, etc. If you are using a simple hand drill, you will need both of your hands to keep the drill steady.
    2. Measure exactly where you need to drill and mark it so you can see it. Bonus Tip: Our favorite method for marking a hole is to use a punch or something similar. This allows the “drill bit” to find the location more easily.
    3. If you need to find the center point on a part, measure your length and mark the half way point on all four sides of the piece. Draw a straight line across the center from top to bottom and then do the same from side to side. Your center point is where the two lines intersect. See our tip in step #2 for marking the center point.
    4. If drilling by hand, hold the drill steady and drill slowly. It is very important that the drill not slip. If the drill slips, you can cause damage, drill in the wrong location or even injure yourself or others.
    5. With a hard to drill metal like stainless steel, you need to make sure there is plenty of coolant. Drilling at the proper RPM rate or even slower is a necessity. Bonus Tip: Pushing relatively hard once the drill has started into the work piece can sometimes be helpful. It causes the “drill bit” to cut a larger and deeper chip which keeps the cutting surface of the tool in cool material rather than right at the surface where heat was generated on the previous rotation. Typically, this is useful on automated machinery and not as important when hand drilling.
    6. Generally, slower RPM rates mean better results when time is not an issue. If your cycle time is critical, then work with a tooling supplier to determine the optimal speed and feed rate for your actual material and tooling. We often suggest test drilling on a drill press or milling machine to help determine this prior to purchasing a self feed production drilling machine.
    7. Choose the right drill bit for the job. If there is any question about whether it is the correct tooling, you should contact a professional tool dealer or machinist who can help you.
    8. A cone “drill bit”, step “drill bit” or graduated style tool is sometimes useful for soft metal projects. It is designed to cut various sized holes in thin sheet metals typically but can be used on some other products with success. Typically, these tools are not professional grade though so special order tooling may be necessary if this is part of your plan.The transition or cone can be smooth or it can have graduated steps on it. Sometimes you can use one of these to cut a whole range of sizes of holes. Simply drill to the diameter you wish and save the time and cost of switching out tooling. AutoDrill Production drills can be adjusted to repeat the same depth of drilling to an accuracy of 0.001″ to 0.003″ on average and are easily adjusted by the end user to lock in this depth for maximum efficiency and repeatability.Bonus Tip: If you lack horsepower on your machine and you can’t use a cone or step drill to manage the drilling load, start with a smaller size tool. Gradually increase the size until you get the dimension you are looking for.Bonus Tip:When using a multiple drill spindle head, you can often stagger the tooling lengths to minimize the horsepower requirements. AutoDrill even manufactures custom gang drill / multi-drill heads with different length spindles if necessary.
    9. Get better tooling for more difficult jobs and harder materials. High-speed steel (HSS) drill bits are often coated with a special aluminum nitride layer and are good for most metals. Avoid using them without coolant and proper speed and feed rates on aluminum as the metal debris or chips tend to become stuck or “welded” to the tooling. This can often make clean hole drilling impossible. It can increase the burr on the top or bottom of a part, create an over sized hole, create poor hole quality, etc.There are cheap imitations out there. If you need a real tool, we suggest going to a tooling distributor rather than a local hardware store, etc. Here are two massive online sources for tooling: McMaster-Carr and MSC Direct (…There are others, but this will get you started in the right direction.)
    10. There are higher quality tools made such as Cobalt, TiN, Carbide or even Diamond. Keep in mind that some tooling simply is not made for smaller drilling machines. Micro vibrations caused by a lighter weight machine (i.e. not 10,000 lbs for example!) can cause the most expensive and durable tooling in the world to prematurely dull because the vibrations destroy the cutting edge.
    11. Take your time to do the job safely and cleanly. If you do not use caution when drilling metals, you may end up with holes that are out of round, and there is no fixing that problem. As we have said before, there may not be time to do it right the first time according to the pressures and deadlines… But there always seems to be time to do it right the second time. Just do it right the first time, every time!
    12. Bonus Tip: When working in the shop, chaos is your enemy. Act like a surgeon. When you take a tool out and use it, replace it immediately after finishing the job. Many people have been injured and many jobs have been ruined because someone thought they could clean up at the end of the day or at the end of the job.
    13. Beware of metal bits, chips and curls flying or spinning around. Always wear safety glasses and any other safety equipment when drilling metals.
    14. If you are the one setting up a manually triggered production drill, consider ordering a Two Hand Anti-TieDown (THAD) start button assembly. This forces the end user to press two buttons at the same exact time in order to start the drill. This can help eliminate injuries in your shop or in your customer’s shop! Do you really want your customer filing a lawsuit against you for not properly protecting their employee? It may not be right, but the legal system unfortunately allows them to do it so prepare now.

Please CONTACT US to discuss your application and receive prompt product cost, literature and technical help.

How to Select the Proper Drill Bit Tool

Important Note: This write up covers only the very basic details concerning the subject. Please contact us for more detailed information, especially if it concerns your production, or other high volume drilling needs.

Metal drill tooling, often called “drill bits” are the most common you will encounter when searching for drilling tools – we will just call them drill bits from here forward since that seems to be the acceptable term for most.

The design of a drill bit for metal drilling depends on various factors such as:

  • The material you need to drill a hole in
  • The volume of drilled holes
  • The speed in which you must drill the hole
  • How deep the hole is or how thick the material is
  • What direction you will be drilling in (horizontal, vertical, some combination of both, etc.)
  • The finish you want to create, such as a screw head either exposed or hidden beneath the surface

Choosing the right drill bit becomes easy once you are experienced at drilling a wide range of materials. We hope that this basic write-up will help you to set up a very efficient and profitable scenario for your business.


Check that the drill bit is the proper type for the job. AutoDrill suggests talking to your tooling supplier to choose the right drill bit type. Here are some very basic guidelines…

  1. Standard steel drill bits are good for most simple drilling jobs such as most plastics, most woods, aluminum, brass, bronze, cast iron, etc.
    HSS or High Speed Steel drill bits are good for some of the more difficult applications where you are drilling structural steel, slightly hardened steel, stainless steel, etc.
  2. Cobalt, TiN coated or even carbide or diamond drill bits are sometimes needed for materials such as tool steel, stainless steel, stone or ceramics, or even woods such as ipe that have silica nodules within the material, etc.
  3. High helix drills can be useful when drilling deep holes where removal of the chips or debris can be difficult.
  4. Reduced tip or pilot drills are useful when drilling into surfaces that are rounded or when you need the drill to stay “on target” better. This also helps when you have less than adequate horse power on your drilling machine.
  5. Split point drill bits are useful for rounded surfaces, drilling at a slight angle, etc. They start much more easily than a standard web tip drill and lower the thrust required to start and maintain a drilling process.
  6. End mill-type drills are used when you can not use a drill bit with a tapered tip.
  7. A spur-point bit is useful for most jobs around the home, its design ensuring a straight hole.
  8. A tile bit, as the name suggests, is best for drilling ceramics.
  9. A flat wood bit creates a large hole, but requires a powerful drill.
  10. Masonry bits are suitable for drilling through stone.

Pick a size of drill bit. This obviously depends on your job and desired hole size when you are done. Drill bits are still measured in fractions of an inch for most of the USA although metric sized tooling has become much more common. Typically, they come in 1/32″ increments although tooling can be acquired in 0.001″ increments or smaller when necessary. The four most common drill size options are:

  1. Fractional (Generally starting at 1/64″)
  2. Metric (Generally starting at 1mm)
  3. Number drills (1 to 60 typically but others do exist)
  4. Letter drills (A to Z)

Select the design of drill bit that will work best for your specific application. We strongly suggest speaking to a tooling expert if this choice is difficult to make or the application is critical.

If drilling into wood or any material where a common fastener will be used, decide if you want the fastener head exposed above the surface of the material. If you want it recessed or hidden (on a wooden cabinet, for example) select a step drill bit or one with a countersink or counter bore attachment / provision. The drill bit widens the hole at the end so the fastener’s head is hidden below the surface a bit.

BONUS SUGGESTION #1: If you are looking to drill a very large number of holes in a manufacturing or production drilling environment, we suggest you experiment with different drill bits from different suppliers during your initial set-up process. Determine which create the highest quality hole, last the longest, throw the chips or curl best for your fixture, provide optimal drilling stability, etc. Using the right drill bit for the right material is always important.

BONUS SUGGESTION #2: If you are about to purchase a production drilling machine for an application, keep in mind that they are often highly efficient versions of manual drilling machines. You can often test your process on a drill press or a Bridgeport type milling machine before spending your hard earned cash on a selffeeder unit.

Please CONTACT US to discuss your application and receive prompt product cost, literature and technical help.

How to Drill a Hole in a Metal Plate

Important Note: Whenever you are drilling into any metallic surface, a cutting fluid or similar product will most likely be of great benefit to you.  It decreases friction between the tool and the material which lowers heat build-up. Because there is less friction and heat, tooling life is extended and your profit increases with the more efficient drilling set-up.

Drilling into significantly thick metal plate is not the same as drilling into thin material or soft material such as wood or plastics. When drilling through thin materials, the “drill bit” goes through the material very quickly. This means there is less heat build-up at the tip of the tool. Drilling into a thick metal plate takes longer and as the tooling rotates over and over again through the material, heat builds up. If you do not properly manage the heat build up, you wind up dulling the “drill bit” prematurely. The key is to reduce that heat build up as much as possible.

Basic Manual Drilling Instructions

  1. Place your metal plate flat on your work table surface. Make sure that the area where you will be drilling has clearance below it by either placing the area over a preexisting hole in the table top or by placing the area over the edge of the table a bit.
  2. Secure the metal plate to the work table. Do this by placing C-Clamps or some other similar clamping device on the edge of the plate. NOTE: If the plate is not securely tied to the stable table top, it could spin wildly causing damage or injury! This is a critical step.
  3. If you are drilling a hole 3/8″ or larger, we suggest that you select a “drill bit” that is 40% to 50% smaller than the size of the final hole to be drilled. For example, a 1/2″ diameter hole would likely be drilled 3/16″ or 1/4″ first. This is called a pilot hole.
  4. Put on your safety glasses. Apply cutting fluid to the “drill bit” as well as on the plate at the location where you will be drilling. Place the tip of the “drill bit” on to the surface of the plate.
  5. Apply pressure on the hand drill and pump the trigger of the drill so that the rotational speed of the “drill bit” varies from stopped to running speed. Begin to run the “drill bit” into the metal plate. Keep pumping the trigger of the drill as it will keep the tooling spinning at a slower speed. Slower speeds mean less heat build up. remember that heat is your tool’s enemy! Pause drilling and apply cutting fluid to the drill bit often to keep the drill bit cool. As long as the tip is wet with fluid, you are doing fine.
  6. Take care as you break through the final thin piece of metal when drilling. As the tool starts to break through, let up on the downward pressure. Failure to do this can sometimes make the drill bit “screw” through the material and pulls the drill down rapidly to the surface. It can also greatly increase the size of the “burr” on the back side of the plate.
  7. When you have finished the first hole, exchange the smaller “drill bit” for the properly sized “drill bit” required for the final hole. Again, coat the drill bit liberally with cutting fluid as well as the area around the smaller hole you just drilled. Get some fluid into the smaller hole if possible.
  8. Repeat step 5 above, this time with the larger “drill bit” until the hole is complete. When finished, wipe the excess cutting fluid from the surface of the metal plate using a dry rag and clean up any metal chips, etc. Be careful that you do not cut yourself on the sharp edges or chips that were created during the process.

Please CONTACT US to discuss your application and receive prompt product cost, literature and technical help.