What Size Drill Bit for a #10 Screw? [Answered]

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In most situations, a #10 screw calls for a 1/8” straight drill bit. However, the ideal size of the drill bit can vary depending on the material you’re using, and you’ll need a narrower pilot hole when working with soft materials.

Screw SizeDrill Hole Size (Softwood)Drill Hole Size (Hardwood)
#65/64″3/32″
#83/32″1/8″
#107/64″1/8″
#121/8″9/64″

For a #10 screw, the closest match you can get to the diameter without the threads is a 5/32” straight drill bit. This translates to 0.156” or 3.97 mm.

If you need to create a tapered pilot hole, a slightly larger diameter tapered bit would be suitable. An 3/16″ or 0.1875” (which is approximately 4.76 mm) bit is your best choice.

How to Use a #10 Screw

Once you’ve determined the proper drill bit to use with your #10 screw, its time to get to work!

Step 1: Select a Drill Bit

To select the proper drill bit, you need to know the appropriate size and depth of the hole to be drilled. In addition, pilot holes are essential to ensure the wood doesn’t split, especially while working with screws.

Learn the correct pilot hole size to drill for hardwood and softwood for every screw size there is, ranging from a #2 screw to a #24 screw
  1. The pilot hole must be drilled with a drill bit whose diameter is the same as the screw to be used, minus the dimension of the screw’s threads.
  2. If you intend to thread the hole drilled for screwing the bolts in, that is, you plan on tapping the drilled hole; you need to know the proper pilot hole size for the bolt you plan to thread. Screws can be driven easily using a screwdriver when using hand drills.
  3. The most frequently used bits are twist drill bits used for drilling on standard materials like wood and metal. They are used to make smaller cuts.
  4. To make large holes, you must begin with smaller drill bits and then slowly widen the holes. Starting with a large drill bit directly can lead to the formation of sloppy holes. 
  5. The danger of getting sloppy holes increases when the hole is drilled larger than a quarter of an inch in diameter.
  6. To drill large holes, one can use Forstner bits which can go wholly or partially into the material being drilled, depending on the strength of the material. They can also be used to drill angled holes.
  7. Spade bits can be used for the same operation as Forstner bits, but the former is specially designed for usage on wood. Hole saw bits can also make holes into wood. However, hole saw bits cannot be used to make partial cuts.
A focus close up shot of thin drill bits

Thus depending on the need, one must choose the proper drill bit. For example, the size of drill bit needed for a #10 size screw is one-eighth of an inch, and the size of the pilot hole is 7/64″ inch.

This article has more details on the size of drill bits needed.

Step 2: Put the Bit You Chose Into the Drill

Loosen the black circular section in front of the drill, which is known as the chuck. Twist it in an anticlockwise direction to loosen the jaws used to clamp the chuck onto the drill bit.

  1. Take the shank of the drill and put it inside the loosened jaws of the drill bit. Now tighten the chuck so that the shank is tightly held firmly at its place.
  2. The bit should be perfectly centered, and the jaw should tightly clamp the flat sides of the shank. Don’t tighten the jaws near the flute of the bit to prevent them from breaking. The flute is more prone to breaking if the size of the drill bit used is small.
  3. A quicker way to tighten the chuck is by holding the chuck alone and not holding the drill bit. Then run the drill in a clockwise direction. Then hold the chuck and rotate it in the counterclockwise direction when you need to loosen it.
Inserting a drill bit to the drill

Step 3: Check Other Settings

After the drill bit is set, you need to check if the battery inside the drill is completely charged. A drill with insufficient charge can lead to slow and imperfect drilling.

  1. Set the speed of the drill at the right setting. The first switch to the left is for high torque and low speed, which can be used to drive screws into any material. For drilling holes, use the second switch ensures a high speed and low torque.
  2. A faster setting is needed for most of the common tasks done using a drill, while for making deeper holes, you will need a larger torque.

It is essential to check that you are drilling in the right direction. When the drill bit is faced towards you, counterclockwise movement is for cutting, and clockwise movement is for removing the bit.

Step 4: Set Up the Material

The material to be drilled must be held tightly by a sturdy vice or clamps. You can consider placing a piece of wood under the material to be used for getting better results.

You must ensure there is enough space to prevent the drill bit from drilling into the table. Proper marking of the holes before drilling is essential for getting the best results.

Step 5: Drill the Hole and Check It

Before you start drilling, you must ensure the drill bit is in contact with the material to be drilled. Hold the drill bit at the perfect angle before you begin to drill.

Pull the trigger of the drill and make the perfect drill. After the hole is made, you need to check if the hole has the desired diameter. Then, pass a screw into it, and see if it just fits.

If it completely passes through, it means the hole is too big, and if it refuses to go in at all, it means the hole is too small. After the drilling process is over, clean up all wood shavings and drilling items, as it may cause accidents if someone is unaware of their presence.

This video will help you understand how to determine the drill size. I also have articles on finding the best drill bit for a #6 screw, a #7 screw, a #8 screw, and a #12 screw.

Frequently Asked Questions

A close up shot of a drill bit

How Big Should The Pilot Hole Be?

Always remember the size of the pilot hole should be the same as the diameter of the root of the screw. The reason for this is, the exact diameter helps hold the wood grain without splitting it during screw insertion. Despite this, you can still connect two boards using the threads.

Should The Drill Bit Be Smaller Than The Screw?

Without the threads, the size of the drill bit should always be equal to the shaft of the screw. You can easily measure it by placing the drill bit and screw beside each other. If they are of the same size, then you can proceed.

How to Choose and Use Drill Bits | Ask This Old House

Conclusion

Choice of the drill bit size is a simple but essential step to be taken before the drilling operation. If you carefully find the model of your drill or make sample holes, you will find the perfect drill bit size and have an easy time drilling.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.