The similarity between auger bits, spade bits, and hole saws is pretty obvious; they are used for drilling holes. However, I do know for a fact that a lot of people tend to confuse the specific applications of each.
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I used to be one of those people, but as I gained some hands-on experience, I eventually learned the numerous differences between the three. So, this article is basically my attempt to help you understand the key ways in which these three types of drill bits differ.
What is an Auger Bit?
Auger bits are spiral-shaped drill bits used to drill deep holes in wood. The way they are designed makes them ideal for removing any dust and debris from the borehole. In other words, they rarely get stuck inside the target material.
Similar to other “wood” bits, the auger bit has a sharp, pointy tip right in the center to help you get a precise location before and during drilling. The difference here is that the auger bit usually has a screw thread which helps to easily pull the drill bit through the material.
Auger bits have seen a wide range of use for decades, both by DIYers and professionals, mainly in the domain of construction.
What Are Auger Bits Used For?
The first noticeable thing (or two things) about auger bits is the fact that they are both long and strong, making them ideal for drilling deep holes.
They also excel at removing most of the material from the holes, greatly reducing the risks of jamming or clogging as a result.
Additionally, the way they are designed, combined with their sturdiness, makes them viable both in power drills as well as hand-powered ones. The latter is very useful in tight spaces, where there may not be enough room for a power drill.
Auger bits are a favorite amongst locksmiths, who use them to create mortises in thick wooden doors. There is a much larger version of the auger bit called the earth auger, which is used to dig holes for posts and such.
What Is a Spade Bit?
Spade bits, also known as paddle bits, feature a wide, flat blade resembling a paddle. They see widespread use by plumbers, and electricians rely on them to drill holes in walls for pipes or wires. You’ll also find them in some woodshops since they can be used in certain woodworking projects.
The flat blade of a spade bit has a pilot point that can dig into the material you are drilling. This helps to get accurate positioning and it also keeps your bit from walking over the material.
Spade bits usually have a round shank with a ¼” hexagonal profile at the end. It can be chucked into both quick-chuck impact drivers or self-centering 3-jaw chuck of cordless drills.
Both edges of the flattened portion of the spade bit are sharpened and have two pointed tips at the outer edges of the sharpened area. As the bit turns, the two sharpened bottom edges start to dig into the lumbar, getting wood out of the hole much like a corkscrew in action.
Spade bits are meant for running at high speed. Do not use these bits on metal or any hard material. They are designed to drill through soft materials such as wood and plastic. With new bits, you can often get very long shavings when drilling through. As the edges get dull you will get broken shavings and dust.
What Are Spade Bits Used For?
Spade bits are the obvious choice if you want to quickly drill holes in wood, and having a smooth result isn’t a priority. In many situations, the roughness of the holes they produce is not an issue, mainly because they are partially or fully covered eventually. Take electricians or plumbers, for example; they drill holes through timber and insert wiring or pipes, so you wouldn’t be able to tell how rough or smooth the holes are.
Spade bits are best used on softwoods; however, they can also drill chipboard, fireboard, plasterboard, and hardwood just fine. And you can either equip them on regular drills for normal use or impact drivers for drilling holes in thick hardwood.
What Is a Hole Saw?
It is a ring-shaped blade with cutting teeth on the periphery. The cylindrical-shaped saw blade is mounted on an arbor, that holds the moving components together.
The hole saw has a drill bit attached at the center of the arbor in order to help you make a precise starter hole prior to the cutting process. This pilot bit also acts as a guide to prevent it from wandering when the peripheral teeth start cutting.
The hole saw is attached to the drill chuck via the arbor and is then rotated at high speeds to cut whole in a wide variety of materials, including wood, metal, plastic, and more.
It works more like a Forstner bit. However, unlike a Forstner bit the hole saw has a large number of cutting teeth and you cannot use it for blind holes.
What is a Hole Saw Used For?
Hole saws are used to cut smooth, round holes in a wide variety of materials, primarily wood. One key difference between them and other wood drill bits is their ability to produce much larger holes.
It is often used to create large, circular holes where drainage pipes and plumbing fitting belong. All you need is a hole saw and an arbor, and you’re good to go. Have your power drill rotate at high speed, and the rest is like a knife through butter.
However, if you’re still unsure about the specific uses of hole saw, here is a list that I compiled:
Door hardware installation
Hole saws are often used to drill holes in doors where hardware such as locksets and deadbolts is installed.
Installing drainage pipes
If you need a hole somewhere in the house for drainage or waste pipes, a hole saw can quickly and efficiently cut you one.
Making holes for pipework and plumbing
Hole saws come in a wide range of diameters, making them the perfect choice for cutting out holes for plumbing and pipework.
If you need to make some extra connections in pre-existing pipework, hole saws should be your choice.
Installing light fixtures
You can use a hole saw to cut out holes in the ceiling to install light fixtures and fittings.
Drilling holes for electrical cables and wiring
If an electrician ever came by your house, you have probably noticed them using a hole saw to create access points for wiring and such.
Cutting vents in masonry
A diamond hole saw can easily cut through masonry, producing holes for air vents or pipes.
Making a birdhouse
Hole saws will make quick work of an entrance hole in a little birdhouse or two that you can have hanging around in the garden.
Differences Between the Tools
The following comparison table shows the key difference between auger bits, spade bits and hole saw.
|Auger Bits||Spade Bits||Hole Saw|
|Designed with helical grooves like a twist drill.||Flat blade with two cutting tips at the edges.||Ring shaped cutting tool with peripheral cutting teeth.|
|Screw shaped pointed tip||Sharpt point in the center||Pilot twist bit in the center|
|Excellent chip removal||Average chip removal||Poor chip clearance|
Ability to drill deep holes in wood & plastic
|Ability to drill large diameter holes fast and for blind holes.||Excellent for large diameter holes with clean finish.|
Slow material removal rate
|Resulting hole has poor surface finish||Cannot drill blind holes. Removal of cut-off piece takes time.|
Spade Bit vs Hole Saw
Hole saws are small ring-shaped attachments that you can add to the end of a power drill to produce smooth, sizable holes. These holes are usually neater and wider than spade bits.
However, hole saws cannot create partial holes, whereas spade bits excel at it. For example, you could use the paddle bit to drill a counterbore. Additionally, they don’t get plugged with cut-out material as in the case of hole saws.
Auger Bit vs Spade Bit
The first noticeable difference between these two is the fact that auger bits don’t require as much effort to operate as spade bits.
Additionally, auger bits clear out chips or shavings from the hole more efficiently than spade bits due to their unique design.
However, all these advantages come at the cost of speed. In other words, if you want to make a quick work of a hole and having it done cleanly isn’t a priority, you should use a spade bit instead.
Auger Bit vs Hole Saw
Hole saws produce holes with larger diameters, yes. But they fail to produce holes as deep as those of auger bits.
Simple, auger bits for deep, small holes, hole saws for shallow holes with larger than usual diameters.
There you have them, the differences between auger bits, spade bits, and the hole saw. Hopefully, you now know which type to use for what.
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