*
Drill bits come in a wide range of size to ensure each project can gain completed with precision. Every one provides a various naming convention to encourage accuracy, consisting of letters, numbers, and also fractions.

You are watching: What size drill bit for #8 screw

When you measure drill bits infractions, every one of them space a ingredient of 64ths. That way the smallest one is 1/64, while the largest size is 63/64. You would then alleviate them to the shortest fractional equivalent: a 2/64 little bit would actually be a 1/32.

You’ll likewise see numbers that go from 1-80, v the biggest number being the the smallest drill bit.

When you pick the drill little size for #8 or #10 screws, several different features need to be component of that choice. You need to account for the screw type, the products used, and also the thread design.

Pilot feet Drill little Size Chart

What dimension drill little bit should you use for pilot holes for wood screw? This comfortable pilot hole size chart should assist you.
Screw SizePilot hole dimension for softwoodPilot hole dimension for hardwood
#21/16″1/16″
#31/16″5/64″
#41/16″5/64″
#55/64″3/32″
#63/32″7/64″
#73/32″7/64″
#87/64″1/8″
#91/8″9/64″
#101/8″9/64″
#129/64″5/32″
#145/32″11/64″
#1611/64″3/16″
#1813/64″7/32″
#207/32″15/64″
#241/4″17/64″

Why Pre-Drill a Pilot Hole?

Since screws have a sharp finish to them, why is it crucial to pre-drill holes to accommodate the fastener?

It is true that the self-tapping screws can quickly penetrate into softwood v the help of a drill driver or an influence driver. However, as soon as it concerns larger diameter holes and also tough products such together hardwood and metal you will have to drill pilot holes. These pilot holes make it much much easier to place the screw in the correct location. Once you have multiple boards come fasten, this work-related guarantees the the products won’t crack or the screw breaks off while working.

When threading thick steel plates, you should drill the hole to the dimension of core diameter and use a threading tap.

When you occupational with hardwoods, the pilot hole need to be the size of the screw’s “minor diameter.” It deserve to be slightly smaller sized for softer woods.

If friend skip the pilot feet (or drill one the isn’t big enough), inserting the screw can cause hairline crack to type in the material. This trouble is especially prevalent in MDF, plywood, and also engineered products, but it can additionally occur in solid wood.

Although you could not view the cracks at first, castle can eventually widen together the environment ages. If given enough time, your lumber joint or fastening work will eventually fail.

Enlarge the Pilot feet in a top Board

If you fasten two timber products, shot to do the pilot hole much more extensive in the top board than the bottom one. This style makes it simpler for the screw to traction the item together.

For this step, the clearance hole should be at the very least the dimension of the major diameter because that the screw.

When this step gets skipped, you’ll regularly see a small gap between the 2 boards or surface jointed together. Relying on what you’re making, glue might seal the bond through this result, yet it isn’t efficient if her spacing is larger than the thickness the a traditional sheet of printer paper.

What size Drill bit for a #8 Screw?

If friend have type A, AB, or B self-tapping screws or form 25 thread-cutting screws, you’d need a #29 drill bit for her pilot hole.

When you have actually high-low thread-forming screws, the suggested drill little for a #8 screw is the #30 for products with a flexural modulus of more than 200,000 PSI. If you have materials that price under that figure, a #31 drill little is a better choice.

If you are using #8 hammer drive or U-drive screws, her pilot hole’s encourage drill little size is #27.

When you should use standard wood screws for your project, the straight size is 1/8-inch for the #8 screw. If you require a tapered result, an 11/64-inch little works much better for hardwood, if a 5/32-inch little bit is perfect because that softwood. You’d usage a C8 countersink.

What size Drill little bit for a #10 Screw?

If you have type A, self-tapping screws, type AB self-tapping screws, kind B self-tapping screws, or form 25 thread-cutting screws, you’d require a #21 drill bit for her pilot hole.

When you have high short thread forming screws, the suggested drill bit for a #10 screw is the #27 for products with a flexural modulus of an ext than 200,000 PSI. If you have actually materials that price under the figure, a #29 drill little is a far better choice.

If you space using #10 hammer drive or U-drive screws, the recommended drill bit size for her pilot hole is #20.

When her project provides hardwood or softwood, a typical #10 wood screw is suitable for the fastening work. You’d usage a 9/64-inch little for a right pilot hole, although part softwoods might benefit from having a 1/8-inch bit.

If you require a tapered pilot feet for your project, hardwoods would need a 13/64-inch bit, when softwoods would use a 3/16-inch little for the #10 screw. You’d desire to use a C102 countersink.

See more: What Does Tyler Mean In Greek ? Meaning Of The Name Tyler

Once you have actually the tools ready, it help to clamp her boards gently to ensure they don’t move. Drill native a completely vertical or horizontal position to create an accurate pilot hole. ~ that work-related is finished, you deserve to place the #8 or #10 screw through precision to make a for sure bond.