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Drilling Perfect Holes
Woodworking Class
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Lesson 5: Drilling Perfect Holes
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Drilling holes in things isn't difficult, but knowing a few tricks can improve your projects dramatically. In this lesson the basics of power drills will be covered, as well as techniques for drilling small and large holes.

It seems simple, but there's lots that can go wrong when drilling from wandering drill bits, holes that don't line up, and tearout. Understanding the tool limitations and how the bits work is the best place to start, at the end of this lesson you'll be a pro in drilling.

Putting the knowledge to use in a practical application we'll make this upcycled bottle vase that highlights a few different drilled openings

This fundamental skill in woodworking will be used in almost every project you make, and with a little practice will become second nature. Most of this lesson can apply to both corded and cordless power drills, but for this lesson I'll be exclusively using a cordless drill.


Torque and Speed

Most of today's power drills do double duty and can be used to drill openings and drive screws. You may not have noticed but most drills actually have settings on them which you can dial in for different applications - some fancier models even have a speed control which you can change from low to high, giving your drill an ever wider range of settings.

Torque Selection (Clutch)

The business end of the drill is called the chuck, this is where you insert drill bits. Most drills have a ring of numbers around the chuck, this is the clutch that lets you select the torque for driving screws. You can rotate the ring to choose the torque value of your drill, which will stop the drill from spinning when it reaches a certain amount of resistance: higher the torque value the higher the resistance threshold. This is great when you don't want to over tighten a screw and risk it snapping or boring too far into the wood.

At the end of the torque selector is a drill icon, this tells the drill that you are drilling and have no need to limit the torque (maximum torque).

Torque Selector

Speed Selection

With most drills the rotational speed can be controlled by how much pressure is applied to the trigger, but many drills will also have a speed selector. This allows you to switch from high speed to low, perfect for driving screws (low speed) to drilling (high speed)

Speed Selection


Drilling Vs. Driving Bits

Most drills can handle the double duty of drilling holes and driving screws. There's a few different types of drill bits used to make openings and choosing the right bit is important since different drill bits excel at different things.

Drill Bits:


Helical - Great all around drill, comes in a variety of sizes and lengths.


Spade- Used to drill large diameter holes, point helps keep bit centered.


Forstner - Creates flat bottom holes, perfect for receiving dowels, comes in variety of sizes.


Hole Saw - Drilling large diameter holes, creates a plug of waste material that is pried out after cutting.

Countersink - Used to create a conical hole in your work so when a screw is placed inside the hole to sit flush with the surface of the surrounding wood.


Driving bits are used to drive screws into wood. There's many shapes that correspond to the head shape of the screw you are using. For clarity, "cam out" is when you are driving a screw and the head slips out of the screw head, this can cause the head of the screw to "strip", meaning deform the shape of the head making the screw unusable.

Driving Bits:


Slot - Common style of driver. Advantage is less rotational force needed due to the leverage of the head width, disadvantage is cam out and the driver does not automatically center to the screw.


Robertson - Also called square drive. Advantages are ease of use since screws stay on drive and virtually no cam out, disadvantage is they are not common in some areas (mostly America).


Phillips - Widely used and versatile screw. Advantages are that even incorrect size drive can fit into screws, disadvantage is moderate cam out (though some screws are designed to induce cam out to prevent over tightening).


Torx - Advantages include high torquing and very low cam out, disadvantages are availability to consumer and the accessibility to the right bit when disassembling your work.

Allen - A relative to Torx and can sometimes be used interchangeably. Advantages are low cam out and high torquing ability, disadvantages are that it's uncommon for wood screws (mostly used for machine screws). You probably have a bunch of Allen drivers from IKEA furniture.

This is just a sampling for the many types of screws you're likely to run into. For most projects you'll probably use the most common screw which is the Phillips screw, possibly the Robertson. Start with getting a small selection of each and you'll have most of your options covered for almost all your projects.


Tear Out

While drilling openings into wood you may notice a ragged exit hole, this is called tear out and it can ruin an otherwise nice piece of wood.

The easiest way to prevent tear out is to support your work at the exit point of the tool. Tear out happens because the wood fibers get caught on the drill bit and pushed out the wood, with a sacrificial board supporting the wood fibers at the exit point of the tool you can prevent tear out - this is called zero clearance. To make a zero clearance drill support all you need to do is sandwich another wood board underneath your work, then clamp them together. Zero clearance was explored in previously in Lesson 1 - Tear-out.

If you don't want to use a zero clearance board another trick is if you have a concealed side to your work you can make that side the "exit" side of your drilled opening, leaving the starting point of your drilled opening the "show" side.


Pilot Holes

To make drilling easier and more precise, especially in dense hardwoods, drill a pilot hole. A pilot hole is a hole with a smaller drill bit than your final size.

This smaller hole will help guide the larger bit for the final size of the opening, and also has the benefit of allowing you to see and correct any minor drilling mistakes before committing to the larger bit.


Drilling Straight

Drilling an opening into wood isn't difficult, but you may notice that even the slightest tilt can make your exit hole somewhere you didn't mean to. Some of this can be corrected by using a pilot hole, but you can get consistently straight holes by using a scrap piece of wood that has a squared end.

Honing our skills from Lesson 1 - Making Perfectly Straight Cuts, we can easily make a straight square cut on a scrap piece of wood and then use this as our reference piece to drill straight holes.

Mark where you want to drill a hole, then place your drill bit on the point. Next bring up your squared scrap against your drill bit until the drill bit sits flush against the squared end. You can move the scrap piece around to the perpendicular side of the dill to check both directions for squareness.

A drill press is a fixed tool that is set up just for drilling straight holes perpendicular to the work piece. The next step if you find yourself doing lots of drilling would be to invest in a drill press, it can save a lot of setup time.


Simple Depth Guide

There's going to be some occasions where you'll only want to drill into wood a certain distance and not all the way though. A very easy way to manage drilling depth is to measure from the tip of the drill bit the depth you wish to go, then mark that length with a small piece of tape. Drill down into wood until you reach the tape touches the surface of the wood.


Project Time - Upcycled Bottle Vase With Perfectly Drilled Holes

Applying the drilling techniques we learned, let's try building an upcycled bottle vase.

Tools + Supplies:

I sketched out a rough idea of what I wanted my bottle vase to look like, but left the design loose enough so I could make changes as needed while I was building.

I started by measuring the bottles I wanted to use in the vase, I used glass soda bottles but anything similar would work. Once I knew the dimensions of the bottle I could plan out the dimensions for the holder.

Placing the bottles next to each other I planned out the spacing. These dimensions were transferred over to a scrap board I salvaged from an old desk.

Using the techniques in Lesson 1, a section of the scrap board was ripped with a circular saw to make a long plank of wood the width of my bottle holder. Using the measurements taken this plank was cut into 2 pieces that would be the top and bottom of the bottle holder, and 2 pieces which would be the sides of the bottle holder.

Top piece divided into sections, center points of each section marked.

The top piece was measured and divided into 3 sections which were marked in pencil. To find the center of each of these sections I drew a diagonal line from the corners, where they intersect is the center of the section - this is where we'll be drilling through.


Drilling Bottle Opening

To drill an opening large enough for the bottle neck to pass through we'll use a hole saw. Most hole saws have a common drill core that is shared among all the hole saw sizes. The core has a drill bit that acts as the pilot hole and can easily be screwed into a new hole saw if you want to change sizes. Your hole saw might be a little different, but most are assembled the same way.

To determine what size hole saw we'll need first measure the diameter of the bottle where it will pass through the top piece of our bottle holder and then choose the corresponding size hole saw, rounding up since our hole should be larger than the bottle diameter.


Measure bottle diameter


Select hole saw that's slightly larger than bottle diameter

Once you have the right size hole saw assembled set up your work for drilling. Since the hole saw has a long drill bit we'll need to be aware that we'll be drilling through our work and into whatever is below, I chose to work on top of a sacrificial scrap piece of wood.

Once everything is clamped down to your work surface line up the drill bit of the hole saw on your center mark you made on the top piece of your bottle holder and begin drilling into the wood. Even though hole saws are removing the perimeter of your hole and will create a plug when finished drilling all the way through, they are covering a lot of surface area and can get bogged down easily. Go slow with the hole saw and push gently, allowing the hole saw teeth to do the work.

After drilling you should have a plug inside your hole saw from the wood you just cut, this plug can be easily removed by inserting a screwdriver through one of the openings in the side of the hole saw and working it out.

If your work was clamped properly, and you used a sacrificial board underneath, you should have clean holes in your wood.


Dry Fit

With the openings made, now is a good time to place the pieces together to see how they fit together. If your measurements were correct your pieces should fit together nicely.

You can make the bottles removable if your vertical pieces of wood are long enough, or you can entrap the bottles inside the wood structure. There's no wrong way to do this, it's just personal preference. I sanded my pieces down so the tolerance was very tight, allowing the option to remove the bottles if enough pressure was applied, but would stay snugly inside the piece on their own.


Layout Drilled Openings

To attach the pieces together we'll need to pre-drill the holes, this not only makes screwing the pieces together much easier but also prevents the wood from splitting near the end.

Using a speed square to keep things straight, start by making a line parallel to the end of the top board that is half the thickness of the wood you are working with. I divided this line into 3 segments to give me the location of where the screws will go. To this on the other side and then repeat for the bottom board.

Choose screws that are long enough to penetrate through the thickness of the wood and into the next piece, then select a drill bit that is the same size or slightly smaller than the screws you're using. Keeping your drill perpendicular to the work piece drill your pilot holes all the way though at the marks, remember to use a sacrificial board underneath your work or risk drilling holes into your workbench.

To make sure the screw heads sit flush with the top of the wood we'll use a countersink. The countersink will flare out the top of the drill hole and allow the head to be seated inside the wood. Holding the drill perpendicular to the wood start drilling the countersink into the drill hole slowly, careful not to remove too much material. Check to see if your countersink flare is wide enough by putting the head of your screw into the countersink.


Corresponding Holes + Attachment

Because the screws are so close to the end of the wood, and we're drilling into the end grain of the next piece, it's always a good idea to drill pilot holes to prevent the wood from splitting. With the top piece placed on top of the upright section of wood the drill was inserted through the holes we drilled first and into the end grain of the upright, just enough to make an impression.

Once you know where the drill will land on the end grain we can remove the top piece and drill into the end grain to prevent splitting. It's important not to drill too deep into the second piece of wood, otherwise the screw will have nothing to bite into and the screw won't hold.

Align the top piece of wood with the upright section and slowly screw the pieces together, tighten until the screw heads are seated fully in the countersink. Repeat the same for the bottom section of wood. The structure of your bottle vase is now complete!


Sanding

To clean up any ragged edges and even up the surface the entire piece was sanded with 100 grit sandpaper and then finished with 180 grit sandpaper to give a nice smooth surface.

Don't worry too much about sanding, we'll cover some techniques in Lesson 7 - Sanding. Since this bottle holder is upcycled there's a rustic element which doesn't require a perfect sanding job, the important thing is to have a mostly uniform surface.


Add Finish

The wood I used was scrap from an old desk, and a little light for my tastes. To help give this bottle vase a little personality I used a little wood stain. This darker stain will cover any inconsistencies in the wood color (since it's scrap), and highlight any dents and marks which gives a nice effect.

I used a rag to liberally wipe the stain all over the wood, allowing it to soak into the wood. After a few minutes I used a clean rag to remove any left over stain. If you want a darker color you can apply more coats of stain in the same fashion, allowing about 20 minutes of drying time between applications.

When I was satisfied with the color I left the wood stain to dry overnight.


Display

Once the stain is dry you can put felt pads on the underside of the bottle vase to stop it scratching any surfaces. Insert the bottles and fill partway with water, then add some flowers.


Quiz - Drilling Holes and Openings

{
    "id": "quiz-1",
    "question": "Torque selection for drills allows the drill to stop spinning when a set amount of resistance from the screw is reached.",
    "answers": [
        {
            "title": "True",
            "correct": true
        },
        {
            "title": "False",
            "correct": false
        }
    ],
    "correctNotice": "Correct!",
    "incorrectNotice": "That's incorrect"
}
{
    "id": "quiz-2",
    "question": "It doesn't matter what speed your drill goes, one speed for both drilling and screwing.",
    "answers": [
        {
            "title": "True",
            "correct": false
        },
        {
            "title": "False",
            "correct": true
        }
    ],
    "correctNotice": "Correct! Speeds are different for drilling holes than for driving screws.",
    "incorrectNotice": "That's incorrect"
}
{
    "id": "quiz-3",
    "question": "Pilot holes make drilling larger holes easier",
    "answers": [
        {
            "title": "Yes",
            "correct": true
        },
      {
            "title": "Sometimes",
            "correct": false
        },
        {
            "title": "No",
            "correct": false
        }
    ],
    "correctNotice": "Correct!",
    "incorrectNotice": "That's incorrect"
}
{
    "id": "quiz-4",
    "question": "Which prevents tearout when drilling?",
    "answers": [
        {
            "title": "Zero clearance",
            "correct": true
        },
      {
            "title": "Final clearance",
            "correct": false
        },
        {
            "title": "Drilling in reverse",
            "correct": false
        }
    ],
    "correctNotice": "Correct",
    "incorrectNotice": "That's incorrect"
}

Class Project!

Share your version of the Upcycled Bottle Vase using the skills in this class with the Class Pjoject box below.

Next up we'll tackle all there is to know about sanding.

CLASS PROJECT

Share a photo of your finished project with the class!

Nice work! You've completed the class project