Forstner bits and spade drill bits are very similar in the way that they are usually used for the same tasks. As a result, many people find themselves in a situation where they would have to pick between the two.
If you are one of those people, then you’ve come to the right place as I’m going to thoroughly explain to you the difference between the two and which type you should use.
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What is a Spade Bit?
A spade drill bit is a wide, flat blade that’s used for drilling holes into wood. It’s also commonly known as a paddle bit since its shape resembles that of a paddle. There is a pointy tip in the center of the paddle, which is used for guidance when cutting through wood.
Besides being an excellent choice for woodwork, spade bits are also useful for drilling holes in walls for utility installation hence why you would find Electricians and plumbers using them regularly.
Spade bits are a very inexpensive choice that will do an incredible job at making large holes, perhaps larger than the twist drill bits. Another benefit of spade bits is their operating speed. They get the job done quicker than most of the bits in the market. However, you’ll be sacrificing cleanliness for speed, but we all know that doesn’t really matter sometimes.
These bits are available in HSS bright finish as well as titanium coated bits.
What is a Forstner Bit?
Forstner bits are designed to drill into softer materials, mainly wood. They have a sharp point at their center that looks like a brad point bit and two flat cutting edges, similar to those of a spade bit. Additionally, a Forstner bit comes with two radial blades with sharp edges.
They can be used to drill through materials partially or fully. Their special feature, however, is the fact that you can create overlapping holes with them as well as angled and pocket holes.
When it comes to creating neat holes in softer materials and wood, Forstner bits are superior in every way to regular drill bits. The latter tend to leave rough edges, something that is very undesirable in fine woodworking projects.
Additionally, Forstner bits can easily create angles holes, a feature that I’m certain many of you out there would appreciate very much.
Difference Between Spade Bits and Forstner Bits
The following comparison table highlights the key differences between a Forstner bit and spade or paddle bit.
|Spade (Paddle) Bits||Forstner Bits|
|Flat blade with pointy tip at the center.||Flat blades and peripheral cutting edges|
|Fast cutting operation. Designed for speed.||Comparitively slower material removal rate.|
|Drilled holes have rough surface.||Smooth finish and precision holes|
|Ability to do flat bottom blind holes.||Ability to drill overlapped holes, angled holes and flat bottom holes.|
|Can be re-sharpened||Re-sharpening is more complex.|
|Inexpensive bits||Expensive drill bits|
Spade bits are mainly used for rough drilling in wood. They make for excellent drill bits in situations where speed matters more than potential tear-outs. In other words, they are great for construction work, drilling holes in studs, floor joints, and more.
Spade bits usually come in sizes ranging from ¼ of an inch to 1 ½ inch in hole diameter.
As I have mentioned before, Forstner bits come with a cylindrical cutter around the perimeter in order to help you guide the bit into the target material. More often than not, Forstner bits will have teeth and cutting edges in the cylinder, which helps to cut faster.
They come in diameters that range from 0.3 inches to 2 inches, but you can get your hands on some bits that go up to 4 inches.
If you plan to drill into end grain, neither spade bits nor Forstner ones work well, so I’d advise against this completely.
Spades are like the rough guy who gets the job done but leaves quite a mess every time. This is due to the fact that they tend to start wobbly more often than not.
They also cause splintering when emerging from the workpiece. One way to avoid this is by finishing the hole from the other side. So, if you’re looking for wood bits that will make quick, rough work of some stock wood, then spade bits are the way to go.
Forstner bits, on the other hand, leave holes with much cleaner sides and bottom. The latter will also be flat. In other words, you can easily make specific depth holes.
Think of a Forstner bit as a rotating plane. It literally “shaves” the hole as it drills it. A rotating plane that is not fond of quicker-than-average speeds and high pressure, so be careful!
So, if you want to quickly make a hole, then the spade bit is the obvious choice. But, if you are looking for a well-polished hole, then use a Forstner bit.
Spade bits are constructed with high-speed use in mind, so it should come as no surprise that they are often used with electric hand drills. In addition to wood, you can use them on thin copper and aluminum as well as plastic.
You can also tune up and sharpen a spade to ensure a cleaner cut, something that is extremely difficult with Forstners.
Forstner bits, however, are not high-speed friendly at all and can’t stand that much pressure. They are designed for precision and not speed.
Can I use a Forstner bit with a hand drill? They work fine in a hand-driven drill, but they are more effective and efficient in a drill press due to the extra control.
Personally, I use my Forstner bits in both drill press and handheld drill. You just need a bit of practice to use it with the cordless drill as well as needing to clean out the hole (ironic, I know).
Drill Bit for Flat Bottom Hole
What type of drill bits make a flat bottom hole? Both Forstner bit and spade bit can create holes with flat bottom in wood, plastic, plywood, MDF etc. A Forstner bit is preferred since they create holes with clean edges and better dimensional accuracy.
Which Bit is Better?
Both spade bit and Forstner bit are primarily used for drilling large diameter holes in soft materials such as wood. The only other tool that can produce large-sized holes easily is the hole saw but it has its limitations.
So, if you are working in rough with softwoods, spade bits are quicker, thus superior. But if your project includes fine woodworking, then I highly recommend that you spend the extra money on some good Forstner bits. Trust me. You won’t regret it.