What Size Drill Bit for a 5/8-11 Tap?

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⅝- 11 taps are commonly used for re-threading and cleaning. Much like with every other tap you’re here checking what size drill bit for 5/8-11 tap is since there are a lot of sizing to look up. If you want to know more about the sizing, read further.

What Size Drill Bit for a 5/8-11 Tap?

A ⅝- 11 tap requires a size drill bit of 17/32 inches or 0.5312 inches in decimals. The ⅝- 11 tap is classified as NC or national course just like the 9/16- 12. This means it’s a coarse thread or also known as UNC (Unified National Coarse).

UNC is the term commonly used in the United States and Canada. They have lesser threads per inch and are usually applied deeper compared to fine threads. ⅝- 11 taps are generally used for re-threading or cleaning up threads like the 5/16- 18 taps with a drill bit of 17/64″.

⅝- 11 taps can also be used for general purposes if needed. It can cut into most metal and plastic so it’s ideal for small-scale tapping jobs. They’re not like the ⅝ taps with a drill bit of 17/32” which can either be NC or NF.

Tips for Using Large Drill Bits

Make Use of the Hammer Action

Some drills have the hammer action feature. This allows you to “punch” on a hard surface repeatedly. For example, if you’re drilling through concrete, you might want to turn on the hammer action to make the drilling efficient.

Hammer action is a great feature, especially when using large drill bits for concrete. Concrete is hard to drill without the right equipment.

The hammer action makes a vibration that transfers to the drill bit that, gives it better penetration. This will lessen the time for you to drill on concrete and be less taxing on the drill bit since it’s supported by the hammering motion to penetrate the surface.

Avoid Wearing Loose Clothing

One thing that you must absolutely avoid is wearing baggy or loose clothing when drilling. Remember, you are using large drill bits, so the chance of your clothing getting tangled with the drill is higher than using a small drill bit.

You want to avoid wearing anything loose or anything that can potentially entangle with the drill that will cause an accident. This also applies to your hair if you have a long one. Make sure it’s tied up and kept neatly, or use a hair net.

Wear tight clothing or better protective clothing for drilling. Also, avoid wearing jewelry while drilling.

Don’t Use Excessive Force

Large drill bits naturally make people think that you have to use more power. However, that is not the case. It’s better to focus on precision instead of power. When drilling, you must hold the drill vertically at all times for consistency.

You want to hold a 90-degree angle while you let the bit drill for you. A slight bend could cause the hole to be unaligned, and the exit hole will not be where you want it to be.

It’s wise to not use excessive force that can affect your accuracy and stability when holding the drill.


⅝- 11 taps use 17/32 inches or 0.5312 in decimals for drill bit sizes. It’s mainly used for re-threading and cleaning up threads. Make sure you use the right sizing for it to work effectively.