Forstner bit vs Spade bit

May 01, 2021

Forstner bit vs Spade bit

Hole drilling is common in woodworking, but different drilling bits are used for the work. Forstner bits, spade bits, and hole saws are the tools designed to drill holes in wood or metal pieces. But, it's a struggle to decide which one is the right tool for the application. Forstner and spade bits are brilliant tools, but they offer different cutting methods.

Forstner bits are circular and are split-ring design with a cutting blade forming the ring, a flat blade across the diameter. On the opposite hand, a spade bit is flat in shape with two sharp tips for cutting and a pointy middle tip for guidance. All the differences include:

What is a Spade Bit?

Spade bits are also called paddle bits due to their shape and are used to drill holes in wood. They're used for rough work where speed is more important than the cleanliness of the opening produced.

When drilling through a bit of wood, they tend to splinter it once they reach the opposite side.

What is a Forstner Bit?

Forstner bits allows woodworkers to form holes without an extended "lead screw" essentially damaging the workpiece. In other words, it will enable them to drill clean, flat-bottom holes.

While the Forstner bits today are slightly different in design as they adopted a split-ring design and a "pointy tip" rather than the "lead screw." Their purpose remains largely an equivalent, though.

In applications where the drilled holes' absolute accuracy and cleanliness are essential, Forstner bits are used with drill presses. That said, they will even be used with hand drills.

Forstner Bit VS Spade Bit

Going through the differences listed within the last half of this text should help you determine the winner of the "Forstner bit vs bit vs hole saw" battle when it involves your use case.

Before taking a glance at how the two are different and how that affects their use:

  1. Application

Forstner bits are recommended for drilling holes in hardwood because they're more rigid and have a right cutting area as compared to the bit. They're also ideal for decorative drilling work.

On the opposite hand, spade bits are recommended for utility installation projects like drilling holes through walls for electrical wires or plumbing. If you would like to drill multiple holes during a short time, this is often the simplest one to use.

  1. Clean Cutting: Forstner Bits Produce the Cleanest Cuts

The reason why Forstner bits are ideal for decorative drilling work is that they produce clean cuts. It will be attributed to the blades around the ring, making sure the fringe of the drilled hole is kept neat, with only a few chippings and no blowouts.

These ring blades also add tandem with the inner flat blade that runs across the diameter to supply flat bottomed holes that are very neat.

However, with spade bits, they only have a flat blade with two cutting lips on the edges. It produces rougher edges and is ideal for drilling in hidden surfaces like inside walls for installations where the drilling quality isn't an enormous issue. 

  1. Cutting Speed: Spade Bits Are Faster

While the Forstner bit's planning gives a cleaner cut, it drags the spinning and cutting speed down because there's a more significant area contacting the wood.

Additionally, this extended contact surface creates more heat, and thus, attempting quick cuts by spinning the drill faster might dull the bit or cause permanent damage.

On the flip side, with a reduced cutting area, spade bits cut off the wood with less friction and generate less heat within the process. As such, they cut at a faster rate as compared to Forstner bits.

  1. Angled Drilling: Forstner Bits Do a far better Job

Even though the pointy middle tip is that the one meant to guide the bit into the wood, the outer rim of a Forstner bit plays an enormous role during this guidance, especially when drilling at an angle.

The blade at the rim bites into the wood at the beginning of the cut and this prevents shifting or skipping, which could affect the standard of the sting of the opening.

With a bit, you get a pointy middle tip as a guide, and thus, you would like to use some strength to carry it in position, be it when drilling straight or at an angle.

  1. Precision Vs. Modifiable Drilling

With its circular design, a Forstner bit is right for precision drilling. Its outer rim blade allows for precision cutting at the precise point you would like the opening and creates a clean flat-bottom. It also prevents shifting as you start the cut.

With a bit, however, you'll modify the form of the opening by tilting its sides. It provides you with some customization options because it's possible to carve out a tapered hole or drill a smaller hole than the dimensions of the bit.

Each of the bits is uniquely different, and thus, selection should be supported the form and sort of cut you would like to form.

  1. Size: Forstner Bits offer you More Size Options

Spade bits are usually available in small sizes and with fewer options to settle on from. This bit ranges from 6mm to 36mm, which is the length of the flat blade (diameter of the hole).

Forstner bits are available a right sort of sizes, and these are usually large diameter bits. They will range anywhere from 10mm to 90mm, making them suitable for drilling large holes.

  1. Cost

Lastly, if you're on a decent budget, a bit is that the better choice to buy because it's cheaper. It will be attributed to the very fact that less material is employed to create it (no outer rim).

However, if you'll afford it, a Forstner bit is the most suitable option because it cuts better, as long as it matches your usage requirements.




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