What Size Drill Bit For A 5/16 Tap

Every bit an Amazon Associate we earn from qualifying purchases.

And so you lot've got yourself a 5/16″ tap, now what? You need the matching drill fleck. More than that, since five/16″ taps come in 2 sizes, either an xviii or 24 inch, yous need a drill bit that corresponds to the specific size.

How do you know what size yous need and why the different size drill bits matter? Let'south get into it. Below, nosotros've completed a guide covering everything yous need to know most the 5/16″ tap for both sizes. Nosotros've covered how to figure out what size you need for your 5/xvi″, how to calculate information technology on your ain, and ultimately, what drill bits to get.

Keep reading for an in-depth explanation of what size drill flake yous need for a 5/16 inch tap.

Contents

What Size Drill Flake for 5/16″ Tap?
- How Tap Sizing Works for 5/sixteen″ Tap
- How Do Y'all Calculate Tap Drill Size for v/xvi″?
- Why Do 18″ and 24″ Taps Need Unlike Sizes?
What Size Drill Flake Exercise I Apply for 5/xvi″ Tap?
Get Drilling with a 5/sixteen″ Tap

What Size Drill Bit for five/16″ Tap?

The best overall size drill scrap for the 5/16″-eighteen tap is 17/64″ drill flake, which corresponds to an F drill bit.

Screw Size	Drill Bit	Drill Bit Size
v/16″ 18	F	17/64″
five/16″ 24	I	17/64″

Figuring out what size drill bit y'all need for a 5/sixteen″ tap starts with understanding a bit about sizing differences. When we talk about the v/16″ tap, go along in mind that there are ii measurement variations; an eighteen tap and a 24 tap.

While the two are five/sixteen″ taps, they accept unlike measurements relating to their length and thread pitch. These varying measurements lead the taps to crave other-sized drill bits.

To figure out what size drill bit yous need for your 5/16 tap, look at the tap'due south specific length or thread pitch. From there, you tin can determine the appropriate drill fleck you'll need.

How Tap Sizing Works for v/16″ Tap

Tap sizing depends on several variables, including the tap'south diameter, desired full thread pct, the thread pitch, and the drilled hole size. For a 5/xvi″ tap, either an 18 or 24 inch, the diameter remains the aforementioned, but the thread pitch differs.

The full thread percentage doesn't affair whether you lot have a 5/xvi″ tap or an 8-32 inch tap because it depends on your desired consequence. Typically the whole thread percent ranges between 70 and 85 percent, but most users and professionals recommend lxxx%.

When you accept the specific measurements for the one you plan to apply or own, you can calculate the needed drill flake size.

How Do You Summate Tap Drill Size for 5/sixteen″?

To calculate your tap drill size, you need only a basic agreement of math and what size tap you're using, which is the 5/sixteen″ tap. Showtime, yous need to become the diameter of the tap. Y'all can physically measure the bore or look to the first number in the tap's specifications instead.

Cordless drill placed on top of a wooden pallet

For instance, the diameter for both the 18 and 24 five/16″ taps is 5/16″ or .3125. One time you have the bore, yous can insert it into the formula DH=DMB -.0130(% of full thread desired/Ni). This formula looks a bit complicated, but don't worry.

The DMB is the bore measurement yous figured out to a higher place, .3125.
The full thread percent depends on what size thread you lot want, typically between seventy and 85, but we'll use 75 for this example.
The other variable, Ni, is the other office of the tap. Let'south use the 5/xvi″-18 tap, for example. The Ni for that tap is 18.

Insert the numbers for the five/xvi″-18 tap into the equation to look something like this:

DH=.3125 – .0130(75/18)

And so, solve for DH. You should get around .2583, which you then round up to the nearest drill chip size. In this case, the most relative drill bit size respective to the 5/xvi″-18 tap is 17/64, which corresponds to an F drill fleck.

Yous tin can detect the relative drill flake size with some simple math as well. For example, we establish 17/64 equally the closest bit in relation to the 5/16″-18 (DH=.2583) tap considering, when divided, 17/64 is only a couple of thousands away.

Why Exercise 18″ and 24″ Taps Need Dissimilar Sizes?

The fact is, you'll need a different size drill bit depending on whether you have an eighteen tap or a 24 tap. Then, what'due south the difference between the two? They both accept the same diameter, 5/sixteen″, but the 18 and 24 chronicle to the tap'due south thread pitch, the number of threads per inch.

The number of threads per inch influences the length of the tap. The xviii inch tap isn't capable of producing equally many threads as the 24 inch tap and is, therefore, shorter in comparison. Because of this length difference between the ii taps, they will need unlike drill fleck sizes fifty-fifty though they accept the same size bore.

Selecting what size drill bit for a 5/16 tap

Their lengths directly influence the calculations since thread pitch is a component of calculating the needed drill bit size. If yous ignore the thread pitch component for the 18 and 24 inch taps, you won't become a drill bit that fits, which volition not only forbid the device from working correctly but won't work at all.

What Size Drill Chip Do I Use for 5/sixteen″ Tap?

It depends on the type of 5/16″ tap you have, either an eighteen″ or 24″. Because the 2 take different thread pitches, they'll require various drill $.25 to fit and piece of work correctly.

To save you lot the trouble of going through the sizing formula, a v/xvi″-eighteen tap, you lot'll demand an F drill bit considering it most closely matches up to that tap's drilled hole size measured in inches–the DH we solved for in the previous calculations.

Based-off that formula, the 5/16″-24 tap will require an I drill scrap. Just similar for the v/16″ 18inch tap, the I drill fleck'south measurements most closely relate to the five/16″-24 tap'south DH.

Get Drilling with a 5/16″ Tap

Now that you know the fundamentals behind the 5/xvi″ tap measurements and drill bit sizing, yous can put your cognition to work and get to work using it. Just make sure you're aware of what specific size you lot have–either the v/xvi-xviii inch or the 5/16-24 inch–equally both have unlike compatible drill scrap sizes. Once y'all've got that squared away, become on and get to piece of work.