#1 2 13 tap drill size how to#

We recommend 75% tapping drills unless deep holes in steel are being made.Ĭlearance holes: A clearance hole is large enough for the screw to slide through without being turned.

The downside with drilling a hole that a 100% thread could be tapped into is that it is much more difficult to tap (deeper cuts into the metal), and therefore much more likely to break a tap. More commonly, holes that will create a 75% thread when tapped are used as a margin of safety, and this is what we sell. Most taps drill are sized to drill a slightly larger hole than what a 100% thread could be cut into, typically 75% or 50%. For thread engagements more than 1.5 diameters deep, 50% is usually sufficient. According to the machinery’s handbook, tests have shown that more than 60% thread engagement provides no significant increase in strength. 50% means that only half of the thread height is engaged, and is what you’d have if you ground off the top half of a fully formed thread. Metric fine threads are finer than English fine threads and are rarely used.ĥ0% vs 75% tap drill sizes: 100% engagement of a male and female thread means that both threads are fully formed and fully engaged. Metric coarse threads are in between English coarse and fine threads. If you’re trying to make a hole for an unidentified screw, chances are it’s a coarse thread. So, if you’re deciding between coarse and fine threads for a custom hole, use a coarse thread unless you’re going into sheet metal. This will ensure a tight fit and prevent the tap from stripping the thread.What kind of tap do I need? As explained in the screw guide, coarse threads are much more common, stronger, less likely to jam during installation (cross thread), and faster to install. The correct drill bit will create a hole that is the same size as the tap drill size. It is also used to create threads in metal and other materials. This size tap drill is used for tapping screws and other fasteners. If you are using a 1/4-28 tap drill size, it is important to use the correct size drill bit. Once you know the thread pitch, you can use a chart to find the correct tap drill size. The thread pitch is the distance between threads on the tap. To calculate tap drill size, you need to know the thread pitch of the tap. It is important to use the correct size tap drill so that the threads will be the correct size and will be able to properly engage with the threads on the bolt or screw. This is the size that should be used to create the threads in the hole. The tap drill for a 1/4-28 thread is 0.213. You have successfully drilled and tapped a hole using a 1/4-28 tap!įAQ What Is the Correct Size Tap Drill for a 1/4-28 Thread? Once the tap has gone all the way through the hole, reverse the direction of the drill and back the tap out of the hole. As you tap, the tap will create threads in the hole. Again, start on a low setting and slowly tap 1/4 hole. Next, insert the 1/4-28 tap into the chuck of the drill. Once the drill bit has penetrated the material, increase the speed of the drill and continue drilling until the hole is the correct depth for the tap. Then, slowly drill into the material you are tapping with the drill on a low setting. Start by chucking the drill bit into the drill. To drill the bit with a 1/4-28 tap, you will need: Faster speeds will require smaller bits while slower speeds will require larger bits. Speed: The speed at which you drill will also affect the size of the bit.Softer materials will require smaller bits while harder materials will require larger bits. Material: The type of material you are drilling into will also affect the size of the drill bit.If the drill bit is too large, it will cause the tap to break. If the drill bit is too small, it will not be able to create the threads needed for the tap. Size: The size of the drill bit is important because it needs to be the same size as the tap.

And finally, the speed at which you will be drilling. The next is the type of material you will be drilling into. There are a few things to consider when choosing a drill bit size for a 1/4 tap.

#1 2 13 tap drill size how to#

How to Choose Drill Bit For a 1/4-28 Tap?