What to Know About Forstner Drill Bits?

The Forstner drill bit is a wood drill bit. It is used to drill wide shallow holes in the woodworkpieces. There are types of Forstner drill bits according to the shape of the guide rim. Forstner drill bits are available in different sizes.

Drill bits are essential tools in woodworking. Drill bits are used to drill holes in the woodworkpieces with high accuracy and better finishing. For larger holes, we can’t use regular drill bits, but we can use Forstner drill bit with high accuracy and smooth finishing. So let’s see what the Forstner drill bits and their details in depth.

More than that, there are so many things related to the Forstner drill bits. Before you choose this, you should know these things properly.

What is Forstner Drill Bit?

The Forstner drill bit is a wood drill bit that is used to drill wide holes in woodworking. Forstner bits are a great solution for clean and accurate flat-bottom holes.

The forstner drill bit has a sharp point angle which helps to place the drill bit on the exact drilling point and circular cutting path. The cutting path is sharpened, and it helps to maintain the smooth cutting edge of the hole.

With the help of these bits, you can easily create perfect, smooth holes with no jagged edges or splintering with minimal effort. But you can have a center spur notch of the drill bit in the hole, which helps keep it from slipping while drilling.

Mostly, Forstner drill bits are used in woodworking projects that require precise and clean cuts.

What Are the Types of Forstner Drill Bits?

According to the shape of the guide rim, Forstner drill bits are mainly three types.

01. Saw tooth Forstner drill bit

There are 3-5 sharpened saw teeth in the guide rim. That helps to cut the workpiece easily. Due to this structure, it has aggressive cutting behavior. As well as it can shift the workpiece a little bit, when it start the drilling.

Due to the sawtooth, it can produce rougher cuts on the overlapping holes.

But it will produce lesser heat due to this structure. As well as you can drive this bit faster for drilling purposes.

02. Continuous Forstner Drill Bit

There is a sharp, continuous guide rim in this drill bit. It can save the surface fibers and cut them more cleanly. And they perform well in angle boring and overlapping holes with clean surfaces.

Due to the continuous rim, it generates more heat. We can especially see this on larger-sized bits. So it is important to control the speed of the drill bit. These bits can also dull quickly due to the continuous rim.

03. Wavy Forstner drill bit

Using this, you can have a clean and splintering-free hole. Due to the rim structure, it can remove the cutting chips easily. Overall wavy Forstner drill bit is a great solution for all.

types of Forstner drill bits
Types of Forstner drill bits

How Deep Can A Forstner Drill Bit Can Drill?

Normally Forstner drill bit can drill 3-5 inches or 75mm – 100mm depth holes. But it can increase using the adaptor. Most of the adaptors are 6″ in length, and only hex shank drill bits can be fit on the adaptors easily.

Forstner drill bits can be heated too much when it used for deep drilling. So it is important to feed slowly for the deep drilling tasks.

What are the Drilling Speeds for Forstner Drill Bits?

Forstner drill bits have different speeds of drilling due to their various diameters. When using larger diameters, a lower RPM is always better. So let’s see what are the drilling speed for Forstner drill bits.

Drill Bit Size Inches (mm)Speed in SoftwoodSpeed in Hardwood
1/4″- 3/8″ (6.4 – 9.5 mm)2260750
1/2″ – 5/8″ (12.7 – 15.9 mm)2260540
3/4″ – 1″ (19.1 – 25.4 mm)1460540
1 1/8″ – 1 1/4″ (28.6 – 31.8 mm)1150260
1 3/8″ – 2″ (34.9 – 50.8 mm)540260
Drilling Speeds for Forstner Drill Bits

What are the Sizes of Forstner Drill Bits?

Forstner drill bits are available in different diameter sizes and shank sizes.

Available shank sizes are – 3/8″

Forstner drill bit diameters size in inches and mm

Diameter Size In InchesDiameter Size In mm
1/4″6.35mm
3/8″9.52mm
1/2″12.7mm
5/8″16mm
3/4″19mm
7/8″22mm
1″25mm
1-1/8″29mm
1-1/432mm
1-3/8″35mm
1-3/4″45mm
2″50mm
2-1/8″54mm
Forstner drill bit diameters size in inches and mm

Where to Use Forstner Drill Bits?

Forstner drill bits can be used on power tools such as electric drills, impact drivers, lathes, press drills, etc. It is not possible to use on-hand tools. Because it needs more torque to cut and remove the material. So it is impossible to provide such power from the arm.

Forstner drill bits can be used on wood and plastic products, cutting wood, plywood, solid wood boards, MDF, plastics, furniture, door hinge, desk, etc.

It can use for drilling holes, overlapping holes, elongating holes, and enlarging holes easily.

What are the Differences Between Forstner Drill Bits and Spade Drill Bits?

Forstner drill bit and spade drill bits
Forstner drill bit and spade drill bit

When we consider the Forstner drill bit and the spade drill bit, there is an extraordinary difference. So before you use one of them as an option, It it better to check below comparison table.

Forstner Drill BitSpade Drill Bit
A bit expensiveCheap drill bit
It can be used on larger holesLightweight and easy to use
Slow cutting operationsThe fast chip removal rate
Drilled holes are smooth and cleanDrilled holes are rough
Resharpening is more complexEasy to resharpen
Need for for drillingSelf-driving bits are available
Difference between the spade drill bit and Forstner drill bits

What are the Differences Between the Forstner Drill Bit and Hole Saw?

Forstner drill bit and hole saw are both used to drill wider holes in woods. But there is a huge difference due to their structures.

Forstner Drill BitHole Saw
CheapExpensive
Less cutting capacityLarger diameter holes can be drilled easily
Fast-cutting operation and chip removingSlower cutting rate
Drilled holes are smooth and cleanDrilled holes are rough
Resharpening is more complexEasy to resharpen
Can be stuck while drilling
Differences Between Forstner Drill Bit and Hole Saw


Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.


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