What Is A Spade Bit Used For?

What is a spade bit used? Spade bits are mainly used for mainly rough drilling such as boring holes into 2X4’s, joists, sheet-rock plywood. It’s a handy all around tool to make holes of a larger diameter than regular drill bits. It’s more than capable of drilling not only through softwood but hardwoods as well. 

You’ll use this bit a lot if you’re running new electrical wire to go through joists or 2X4’s as long as the holes that need to be drilled aren’t too deep.

For deeper holes you’ll need an auger bit which you can learn more about here.

Why Are Wood Spade Bits So Long?

Wood spade bits are long so that you can bore deeper holes in thicker wood. The long length of the spade bit makes it easier to reach hard to get to places as well.

The standard length of spade bits are six inches long. They do come in longer lengths such as sixteen inches long. These longer spade bits are normally used when deeper holes need to be bored through timber frames. 

For tight to reach spaces where holes need to be drilled, shorter spade bits can be used. These bits are four inches inches in length. They work very well when drilling holes in rafters where there isn’t much room to move around.

Using A Spade Bit Over A Standard Drill Bit

The best time to use a spade bit over a regular drill bit is when a hole is at least ½” and larger. The reason is most of the time the shank on larger drill bits won’t fit into the chuck of a hand drill. The shanks of spade bits are much smaller in diameter than regular twist bits.

If the hole that you plan on drilling needs to be smooth all of the way through, what you can do is drill a pilot hole all the way through the work piece. Then use a spade bit and drill half way through then drill from the other side at that point. This gives a cleaner cut without all of the splintering.

If by chance the hole needs to be even smoother than that, I would suggest using a forstner bit. They provide smooth walls and bottoms if you don’t plan on drilling all of the way through the wood. Keep in mind that spade bits do cost less than forstner bits if you plan to go this route.

Can You Use A Spade Bit On A Drill Press?

Spade bits can be used in a drill press. This option is best for precise hole depth. The drill press has a depth gauge that you can set so all of the holes that you bore will be where you want them.

Before using spade bits in a drill press, be sure that your work piece is either clamped down or secured in a vice. The reason for this is spade bits tend to get jammed up which in turn can cause the work piece to spin. This could also cause injury.

When they jam up like this it also puts strain on the motor and belt. These types of wood bits will also get jammed when using even a hand drill which can really strain your wrists. So be sure to have a good sturdy grip on the drill when using them.

If you’re using a hand drill and need hole depths to be accurate there is a way to do this. You can measure from the cutting edge of the spade bit up the shank and mark it with a piece of tape of where you want the depth to be. 

Spade Bit Jamming

One thing that causes spade bits to jam is when they start to come out of the other side of the wood. They tend to want to lean over to either side and grab onto more wood as they try to bore through the other side. This in turn can really put a strain on your wrists when using a hand drill.

If you can, go from the other side once the point of the spade bit has gone through the wood to finish the hole. This will help to keep the bit from jamming. 

All spade bits have the possibility of jamming but it’s the larger ones that really can give you trouble. If drilling bigger than one inch, more care should be taken. Another option for larger holes is to use forstner bits since they require lower speeds.

Another thing that you can do if the holes that you’re drilling don’t have to be precise is rock the drill slightly back and forth as you drill. This will enlarge the holes slightly which helps the spade bit from binding up.

What Are The Parts Of A Spade Bit

The spade bit is made up of several parts. The long round part is called the shank. The shank comes in two different types. They are either completely round or hexagonal. 

The hexagonal type is the one that I would purchase. The flats allow the drill to grip so that the spade won’t stop turning when in use. 

In the center of the spade part of the bit you’ll notice a number stamped into it. Of course this tells you the size in diameter that this bit will drill.

Just below the diameter number is a single cable hole which is used for pulling wire. 

The next part of the bit is what actually starts the cutting. Some spade bits come with spurs and they look like small points on the edge of the cutting part of the bit. The spurs cut a cleaner hole than spade bits without them. Either one will do fine for what you want.

The next part is called the lips and this part is what does all of the work. It works by scraping away material as you drill through the wood.

Last but not least is the sharp point of bit. This part also can come in two different styles. The first one is just a point with its own cutting surface and is the most basic one.

This is the center of the spade or radius. You put the point of the spade on the mark that you made and drill away.

The other type of point has thread in it which allows for self feeding when boring holes. Since it’s self feeding it requires less effort which in turn can keep your hand drill from bogging down because you don’t have to apply so much pressure on the drill.

Can Spade Bits Be Sharpened?

Spade bits can be sharpened and there are various ways to do it. The easiest way to sharpen them is to buy a drill bit sharpening machine that’s capable of doing spade bits.

Sharpening machines can be expensive but the spade bit can be done quickly. It takes all of the guesswork out of how to do it.

Another option is to use a file to sharpen the edges. This is probably the least expensive option available. As long as the spade bit isn’t made from HSS or high speed steel this will work fine.

If the spade bit is made from high speed steel you’ll need a diamond file. This type of file is the only thing that can grind away high speed steel.

Spade bits can be sharpened with the help of a bench grinder if you have one. This could be a better option to invest your money since there are other tools that you can sharpen with a grinder.

Decent Wood Spade Bits

Most spade bits are made from what’s known as tool steel. The tool steel also has carbon mixed in with it which gives it strength. This spade bit is the most common and cheapest. Tool steel can be sharpened with a regular flat file. 

The other type of bit is made from high speed steel which costs a little more but they stay sharper longer.

Resources

some good tips for beginners on how to use spade bits correctly.