What Size Drill Bit for a 8/32″ Tap? [Answered]

Are you planning on using an #8-32 tap? If so, then you’re in the right place. One of the questions you might be asking yourself is the size drill bit you need for a pilot hole. I’ll answer that question shortly.  

We’ll also cover the details as to what else you’ll want to consider prior to putting an #8-32 to good use. Let’s get started and determine which size drill bit for an #8-32 tap that you need.

One thing to note is the decimal measurements both in inches and millimeters. The #29 drill bits are measured out to 0.136 inches or approximately 3.454 millimeters. This drill bit can also be used for an #8-36 NF tap.  

Please note that #8-32 should not be confused for fractional tap sizes (i.e: 7/16, 3/16, 5/16, etc.) Also, you will notice that some of the drill bits will need to be determined by inches and millimeters as opposed to the closest fractional size.  

An 8#-32 tap may be the best option for when you want to thread any metal holes for screws and bolts. It’s the one thing you’ll want to do before forging any metal together for some other project. If you are doing a DIY project involving steel or aluminum, you’re on the right track.  

Make sure that you measure the drill bit before you install it on your drill. A proper fitting drill bit will always equal out to perfectly drilled holes. One other thing to note is that if you do not have a tap and drill set, you can always buy one that will fit your budget.

How to Use a #8-32 Tap?

Regardless of size, the concept of using a tap is pretty much the same.

• Prepare your drill: Install the #8-32 tap drill bit onto your drill, just like you would any other drill bit.
• Secure your workpiece: If you’re working with smaller pieces of metal, secure them with clamps to avoid slippage.
• Choose your drill: You can use either a cordless or a corded drill. Remember, cheaper cordless drills might not provide enough power for your task.
• Pre-drill: It’s advisable to create pre-drilled holes or divots using a center punch. This step aids in precision.
• Use oil: Apply drilling oil to the pre-drilled holes. This lubrication makes the drilling process smoother and more effective.
• Start drilling: You’re now ready to drill perfect holes, which will later accommodate screws and bolts.
• Optional manual tapping: If you’re working with thin metal, you could opt to tap by hand. This involves using a T-handle with the 8-32 tap to create threads manually.
• Power drilling: If you’re short on time or working with thicker metal, use a power drill with the #8-32 tap drill bit to drill the necessary holes quickly.

When to Use a #8-32 Tap?

You can use an #8-32 tap when you are working on pieces of metal. If you are drilling with smaller pieces of metal, you can use a handheld drill. For larger pieces, you may want to opt for a drill press designed for metal.  

If you are using a drill press, you want to make sure that the large pieces of metal are clamped down by a vise or C-clamp designed for such pieces. As mentioned before, if you have an #8-32 tap drill bit (#29), you can attach it to the drill and get right to work.  

Once you have finished drilling a hole in the metal, you can test it out by using a screw or a bolt. For best results for screws, a #8 screw will be the best option since its equivalent to holes drilled by #29 drill bits.

Other Considerations for a #8-32 tap?

One of the major considerations to note is the type of metal you intend to use. Understand what kind of metal you’re using. Common choices include steel and aluminum.

• For Steel: Choose drill bits made of cobalt or titanium. These materials have the required strength and durability to penetrate steel.
• Standard Drill Bits: Avoid these for metalworking, as they can easily get damaged.
• For Aluminum: Opt for cobalt drill bits due to aluminum’s low melting point.
• Heat Dissipation: Cobalt bits also dissipate heat quickly, allowing continuous work without frequent breaks.
• Pre-Drilling: Evaluate if pre-drilling holes will aid in your task.
• For Beginners: If you’re new to metalworking, a center punch can help create divots where you plan on drilling, ensuring greater accuracy.

Before Using a #8-32 Tap

It is important that you have the right tools aside from the drill and bit. This includes a center punch and safety gear. Make sure that all of the drilled holes are clean and free of any debris prior to fastening any screws or bolts.  

If you are a beginner, it’s better to create your divots for holes rather than guess where the holes should go. If you plan on using screws, you can find a set of #8 screws since they will fit through such holes and threads created by an #8-32 tap.

Final Thoughts

We hope that this guide is helpful in finding a drill bit for a #8-32 tap. You can be able to drill holes with ease while threading them for the right kind of screws and bolts. The tougher the drill bit is in quality, the more durable it can be in most metal working projects.