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Jobber sized drill bits like these can be purchased individually or in an index like this to keep track of them all.
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This set of “Silver and Deming” bits has a reduced shank for use in a ½-in drill chuck.
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Although not as common, left hand drill bits can be handy for extracting broken bolts and screws.
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These carbide tipped bits make quick work of holes in projects and create very clean edges when kept in good condition.
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The Milwaukee ICE hole saws are a go to cutter for larger holes. Keep the cutting speed down and the teeth well lubed for years of service.
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Available in a multitude of sizes, the stepped drill bit really shines when having to drill round holes in uneven surfaces, light gauges of steel, or just for enlarging a hole already made.
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This example is just as simple as it looks. Whack the back of it with a hammer to create a small dimple in whatever you plan on drilling into. Your future projects and painted surfaces will thank you later.
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Perfect for cleaning up rough edges of freshly cut holes, or simply used to countersink a bolt or screw for protection, these bits always come in handy. Available in multiple sizes, styles and angles, match them to the hardware or project you are working on.
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Not just any old lubricant will do, you need a product that will keep the cutting edges cool, and carry the cut material away, our new hero is SprayOn’s LU208.
Words and photos by Bryan Irons
Carbide tipped? Step? Bi-metal? What should you use to put holes in your projects (on purpose of course)? With this installment of Garage Gear, we hope to make the decision of how to complete your next ‘holey’ project a little easier by covering not only what is available to you for making peep holes in metal, but also which ones will garner the best results.
For starters, wipe the words “Forstner,” “Auger” and “Spade” out of your memory banks. For the most part, those are for wood, and wood is for burning in a campfire after the job is done and a day on the trail is complete. Another one we are going to skip over is punching holes. Although very effective, most machines for punching holes are a little out of the realm of the average garage. Let’s make some metal chips, on with the good stuff!
The garden variety of drill bits are commonly known as a “Jobber” bit and fall under ANSI standards regarding diameter and length as well as the number of flutes and spiral angle. Sizes range from 1/64-in to 1-1/2-in, typically in 1/64-in increments, and you commonly see them hanging on the walls of your local hardware store or DIY centre up to the ½-in size. Larger and less common sizing such as numbered and lettered bits as well as metric are available, but a little harder to locate at times. Conversion charts are easily found if you just need to be “close enough.” For the larger bits, a reduced or “Silver and Deming” shank allows the use of smaller drill chucks to run a larger drill bit. Plenty of different coatings are available as manufacturers claim longer tool life and faster cutting. We have found that proper tool pressure and lubrication make a greater difference to us, more so then the coating used. Different tip angles are available in these bits as well and a basic rule of thumb, the narrower the angle, the better the bit will work on softer materials. The opposite is true for a wider angle. We find that a happy medium of 118-degrees and work for drilling anything from stainless steel to aluminum.
For drilling sheet metal or softer materials such as aluminum, we go straight for a stepped bit, commonly known as the “Unitbit.” Able to make different sized holes in light gauge metals with a single tool isn’t the only advantage; they can be used to de-bur sharp edges, don’t have a tendency to “grab” the material like a normal bit does and are easy to control. Like the Jobber bits mentioned above, we typically see different coatings from cobalt to baby seal bone marrow claiming indestructability, yet we have broken and dulled them all. The sizes you will find them in are geared towards “tradesmen” meaning obscure diameters like 7/8-in and 1-3/32-in. Don’t let this throw you off, the multiple step design means there will be one for your project. We like grabbing ones that have the hole size diameters engraved on the flute(s) for easy reference.
For drilling larger holes or slightly thicker material, a carbide tipped hole saw is our weapon of choice if we can find one. Carbide, being a very hard material, ensures a long life provided they are not shock loaded and a cutting fluid is used. They come in many sizes and work very quickly, but are costly. Different depth examples are available, and like stepped bits, most come in trade sizes, so finding one for a 1-3/4-in hole for your roll bar may be a bit tricky. Greenlee tools seem to be the ones that last the longest in our abusive hands.
Think of a standard bi-metal hole saw as a band saw going in a circle. A centreing bit is used in a mandrel to keep the entire unit going around a steady axis. They are cheap, easy to use, and can be used on a variety of material thicknesses. Normally you will find ½-in up to 5-in diameters at most hardware stores. Long lives can be had with a proper cutting speed, a cutting lubricant, and steady pressure to let the tool work efficiently. Should you break a mandrel bit, they are easily replace and are normally ¼-in diameter. Our Milwaukee set as been with us through thick and thin and work well for notching tubing projects.
Cutting fluids come in all different formulas and snake oil concoctions. Its primary job is to keep the cutting edge(s) of the tool cool and to carry away the material cut. We prefer a petroleum-based fluid like our new favorite SprayOn LU208. It comes in a pressurized spray can making it easy to apply. Water based fluids we find burn off too fast and don’t stick when drilling upside down. General purpose lubricants like WD-40 do nothing but smoke and cloud your shop with fog; leave that to TV personalities with spiked hair, trucks with stacks, and manicured nails. You know who you are.
One of the biggest mistakes we see when drilling materials is the absence of a centre punch. A centre punch allows you to make a small divot for your drill bit to start in and keep from walking across the material and missing the target completely. Whether it is a fancy adjustable pressure style or an old school type you hit with a hammer, pick one up and stop ruining projects. Another no-no is moving the drill around while cutting. Keep the drill in a steady location and use constant pressure to get the job done, using a drill press whenever possible. Keep an eye out for more Garage Gear where we’ll cover drills themselves, what to look for, and other shop equipment to make your next project a breeze.