Tips for Taps – How To Use a Tap and Die Set

For a lot of us, a tap and die set is one of those tools you often don’t thing about until it’s too late. Whether you’re using one for automotive restoration or custom, it’s the only way to accurately create, repair, or clean threaded hardware. It’s also one of the most misused tools in the box if you’ve never used one.

Here are several tips to help you get excellent results when you use a tap or die in the shop, as well as an intro to the tools if you’re still unfamiliar.

 

 

Components of a Tap and Die Set

Taps

Taps are used to cut internal threads inside a hole, allowing it to accept a bolt or screw. There are several types of tap designs depending on the hole being made. Taper taps, for instance, are used to start threads due to its tapered end. Plug taps, on the other hand, cut deeper threads in a pre-drilled hole. Bottoming taps have a flat end, creating full threads to the very bottom of a hole.

Dies

Dies are used to cut external threads on rods, bolts, or screws. Die types usually vary by. The type of handle used to turn the cutting tool. Round dies are commonly used in a specific die handle for creating precise threads. Hex dies, by comparison, are often intended for thread repair and can be turned with a wrench.

Tap and die handles

As noted above, different handles securely hold taps or dies to allow controlled turning. A basic T-handle is often used for taps and round dies. A ratcheting T-handle handle can be more balanced and allow for effective thread cutting with minimal wrist movement. For production work, drill-mounted tap and die chucks vastly improve the speed and accuracy of the work. For this article, however, we’re focusing on manual taps and dies.

Tips for Taps (and Dies)

Select the correct size

It sounds simple but it’s a common oversight: always double-check the size of the tap or die against your work. A mismatch can damage threads. Eyeballing it isn’t good enough. Use a thread pitch gauge to ensure the proper pitch and size before cutting.

Clean the area first

Another seemingly obvious piece of advice but clean your material first. Remove dirt, grease, and rust from the workpiece to prevent debris from ruining the threads or damaging the tap or die.

Use the right lubricant

Apply a cutting oil or thread-cutting lubricant to reduce friction, improve cutting performance, and prolong the life of the tools. In the absence of a true cutting oil, clean motor oil will also work. When cutting threads in aluminum, use a lubricant designed specifically for softer metals.

Start straight

When starting a tap in a hole or a die on a bolt, ensure it’s perfectly perpendicular to the workpiece. Misalignment is a common error that can cause crooked threads or break the tool. Once you’re a few threads in, it can be difficult to start over and realign the tool.

Use a proper handle

Always use the provided T-handle for taps or the die stock handle for dies. This gives you the necessary leverage and control to work efficiently.

Turn gradually

Turn the tap or die slowly and steadily. For every full turn forward, back it off about a quarter turn to break and clear the chips from the cutting path.

Never force the tool

If the tap or die binds or resists turning, stop immediately. Forcing a tap or die can break it, damage the threads, or even ruin the workpiece.

Clear chips frequently

Periodically remove the tap or die and clean out the chips from the tool and the workpiece. Avoid wiping the chips with bare hands, as they can be quite sharp. Instead, use compressed air or a small brush to keep the area clean.

Repair, don’t overcut

When restoring damage to existing threads, use a thread chaser instead of a cutting tap or die, if possible. This keeps you from accidentally removing too much material and preserves the original thread integrity.

Practice first

If you’re new to using a tap and die set, practice on scrap material to refine your technique before working on valuable parts. Ideally, drill the correct-size tap or die in the same kind of material to test your work first.

By following these tips, you can effectively use a tap and die set for high-quality work on your restoration, repair or custom project.