Knowing how to use taps and dies is crucial when working with tap and die sets. “Tapping” refers to cutting or re-cutting threads into a hole or nut. This is a common issue faced by auto mechanics and metalworkers, often dealing with stripped sleeves or cut-off bolts that need to be rethreaded. Mastering the use of taps and dies allows you to efficiently solve serious metal problems that would otherwise leave you in a difficult position.
Table of Contents
- How to Use Taps and Dies
- Finding the Suitable TPI (Threads Per Inch)
- Selecting the Appropriate Tap or Die
- Exploring Combination Drilling and Tapping Bits
- Fixing and Repairing Threads in Bolts
- Securing the Bolts with a Vise
- Aligning the Die and Commencing Re-Cutting Threads
- Rethreading Holes and Nuts with Taps and Dies
- Using a Gauge to Find the Correct Size Faucet
- Securing the Tap and Starting the Threading
When working with bolts or pieces of metal, you use a “die” to cut or repair threads. Thread cutters, such as taps and dies, have superior metal strength compared to most sheet metal. With the right amount of oil and care, you can easily and consistently cut or repair threads on machined screws and bolts.
Finding the Suitable TPI (Threads Per Inch)
Before you start threading, it is essential to determine the threads per inch (TPI). This measurement helps you choose the appropriate tap or die for the bolt, nut, or hole. Many tap and die systems come with a gauge that utilizes various “blades” to match the TPI of a bolt or nut. These gauges resemble pocket knives and are widely available.
Selecting the Appropriate Tap or Die
Once you have determined the TPI of the bolt, you can select the corresponding tap or die. It is important to keep in mind that tap and die kits come in both metric and SAE (Society of Automotive Engineers) measurements. Manufacturers offer kits with different sizes, ranging from small to extensive. Both taps and dies have tapered threads, facilitating easy screwing of bolts or nuts and gently re-engraving the threads as intended. Most dies can be secured using special wrenches, providing the necessary leverage for smooth rotation and guiding during the cutting process.
How about a Combination Drilling and Tapping Bit?
You may have come across new drill and tap bits that allow you to drill and tap in one step. These bits can be used with an impact driver or a drill. While they offer convenience, manual tapping of holes requires more careful handling. It’s fascinating how these bits work, considering the additional precautions.
These combination bits can tap holes quickly if used on recommended materials and lubricated during the process. We have tried them on various sheet metal and steel. The biggest challenge is aligning the holes and maintaining their straight and level position.
Fixing and Repairing Threads in Bolts
Repairing threads on Phillips thread bolts using dies is a straightforward process that involves a few simple steps.
Securing the Bolts with a Vise
To begin, secure the bolt in a vise. It is advisable to only clamp the head of the hex bolt to avoid further damage to the threads. If clamping the bolt shaft becomes necessary, there are methods to protect the threads:
- Use a few pieces of wood
- Find rubber material, like a bicycle inner tube, and place it between the vise jaws
- Utilize two pieces of leather
Aligning the Die and Commencing Re-Cutting Threads
After securing the bolts, carefully align the die to ensure straight threading without any tilting. During the tightening process, the die may become hot due to the close metal contact. This is inevitable when metals rub against each other, especially noticeable with longer thread lengths. To keep the die cool and lubricated, apply a small amount of cutting oil. Most tap wrenches have an open top, allowing easy lubricant application without dismantling the die. This practice extends the lifespan of the tap and die set.
As you thread the die down onto the bolt, it will naturally start to seize. To enhance cutting efficiency, occasionally back the die a bit to clear the threads. This is similar to drilling wood with a large drill bit. The process is complete when the die has sufficiently moved down, allowing the bolts to pass through the top.
Rethreading Holes and Nuts with Taps and Dies
Screwing or re-tightening the nut using a tap is just as straightforward as using a die. Begin by securing the nut with a vise.
Using a Gauge to Find the Correct Size Faucet
If you do not have matching bolts, use a gauge to determine the appropriate size for the nut or hole you are screwing into. For those creating their own nuts, it is advisable to use matching bolts to ensure accurate dimensions. This saves you from struggling to fit the gauge into a worn bolt, which may be impossible depending on the location.
Even if you encounter completely broken threads, there is no need to panic. You can always drill the holes and re-tap them for slightly larger bolts. Alternatively, you may choose to fill the holes and re-tap them.
Securing the Tap and Starting the Threading
First, place the tap in the provided wrench and secure it. Next, position the tap in the nut and begin turning it by hand, ensuring a perfectly straight alignment with the hole. Similar to using dies, lubrication is essential. Regularly clean the tap to remove any accumulated debris from the threads.
Using taps and dies can truly resolve challenging situations, even though not everyone requires such tools. However, when the need arises, there is no substitute. Mastery of taps and dies takes time, but eventually, you will develop a feel for the process, speeding up your workflow.