When you need to bore a precise, flat-bottomed hole with no tear out or defects, you’re gonna need to break out the Forstner bit. While hole saw, spade bits and auger bits can all be used to punch holes through wood and other materials, none of them can create the precise, clean holes that Forstner bits can.
Some people are under the impression that Forstner bits can only be used with a drill press, and using one in a handheld drill will lead to inaccurate holes. This is because Forstner bits have a tendency to slip or ‘walk’ on the surface of the wood – leaving unsightly marks and causing inaccurate hole drilling.
While it’s true that boring holes using a Forstner bit in a handheld drill is more challenging, it is by no means impossible. I’ll show you how to drill accurate holes both with and without a drill press, so you can bore perfect holes for whatever project you’re working on.
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How to Use a Forstner Bit with a Handheld Drill
Using a Forstner bit with a handheld power drill means you’ll need to be extra careful to align your drill perpendicular to the drilling material. Unlike other drill bits, the outer edge of a Forstner bit is what guides it through the cut, so you’ll need to make sure this edge is even with the wood during the first few rotations of the drill.
Step 1: Clamp Material onto Backing
One way to ensure you get a perfectly clean hole without tear out on the opposite side is to clamp your workpiece to a piece of wood backing. This will transfer any tear out from your workpiece onto the scrap piece of backing.
This is only necessary if you’re planning to drill a hole all the way through the material. If not you can skip this step.
Step 2: Mark Centre Point & Align Drill
Next, use a carpenters pencil to mark the center point of your hole.
Then, line up the centering spur of your Forstner bit with the center point you just marked. Make sure to hold your drill perpendicular to your workpiece as you start drilling into the material.
It’s important to make sure the bit’s outer edge is evenly in contact with the work surface as you begin the cut. If it’s not, the bit will bore the hole unevenly, and you’ll be left with a hole that’s not completely plumb.
Step 3: Start Drilling
Once you’ve got your drill positioned properly, it’s time to start boring your hole. Holding the drill steady, start drilling at a slow speed until you’ve got the bit’s outer edge etched into the material.
Step 4: Complete Hole
Once the hole is started, you can increase the drill’s speed as you bore through the material. This can take some time, so be patient and stick with it.
As Forstner bit doesn’t have any ‘flutes’, wood chips can build up inside the hole as you drill. You can remove these by retracting the drill occasionally as you go.
Once you reach your desired depth, simply release the trigger and pull the drill out of the hole.
Using a Simple Jig
As mentioned previously, Forstner bits have a tendency to walk or slip on the surface of your material. An easy way to prevent this from happening is by making a simple jig out of scrap wood.
The idea here is to use your bit to drill all the way through a piece of scrap wood. Then clamp this jig in place on top of your desired drilling location and use it to guide the bit into your workpiece. The jig will prevent the bit from wandering – resulting in a perfectly clean and plumb hole.
How to Make a Simple Jig:
- First up, you’ll want to find a suitable piece of scrap lumber. Look for something at least 3/4” thick and with enough room to fit clamps onto.
- Next, clamp your piece of scrap lumber in place with another piece of scrap beneath it. You’ll be drilling all the way through the jig, so you’ll want something to prevent tear out on the opposite side.
- Now position your drill perpendicular to the work surface and carefully drill all the way through. Once you’re all the way through the piece of scrap lumber, loosen the clamps and you’ve got yourself a simple Forstner bit jig.
- To use the jig, simply clamp it on top of your desired work surface, and use it to guide the bit through your desired cut.
How to Use a Forstner bit in a Drill Press
Using a drill press with a Forstner bit results will give you a clean and plumb hole with minimal effort. It’s a lot easier to drill a clean hole using a drill press than a portable drill, as you can apply the necessary pressure without using your body weight.
Step 1: Position and Mark the Workpiece
First up, mark the location of your hole on the workpiece with a pencil or marker. Then position the workpiece at the exact center of your Forstner bit.
Next, clamp the workpiece in place so it can’t move as you drill. If you’re planning on drilling all the way through your material, place a flat piece of scrap wood below your workpiece to prevent tear out.
You can test to make sure the workpiece is properly positioned by lowering the drill’s arm and touching it to the material without powering up the motor.
Step 2: Begin Drilling
Turn on your drill press and slowly lower the bit into the material.
As you cut through the material, be sure to retract the bit often as you bore through the material. This will help keep the temperature down.
Pay attention to the recommended RPMs for your particular bit and be careful not to exceed them. If you do, you can easily overheat the bit and burn the wood.
Step 3: Finish Hole
As you approach your desired cutting depth, slow down the drill press speed. Then keep the bit spinning slowly as you extract the bit from the hole. This will leave a hole with a nice clean edge.
Forstner Bit Uses
Forstner bits have a remarkable number of woodworking uses and can be used in creative ways to accomplish all sorts of boring and cutting tasks.
Because they’re rim-guided rather than center-point guided, you can use them to drill partial, overlapped, and even angled holes that would be impossible with other bits.
- Overlapping holes. Overlapping holes are useful for removing the majority of material in a mortise and tenon joint. They’re also useful for drilling over a portion of an existing hole or drilling a hole overhanging the end of a workpiece.
- Angled holes. Forstner bits can be used to drill a hole at an angle, which is useful for creating pocket screw holes without a jig.
- Partial holes. Partial holes can be used for figure-eight fasteners for tabletops. They’re the only drill bit that can create this type of hole.
- Counterbored holes. A Forstner bit is the only choice for drilling a large countersink hole on top of an existing hole.
- Dowels and cup hinges. A common use for Forstner bits is doweling as well as for concealed cup-hinges in cabinets.
