When it comes to threading, what is the difference between using a tap and a thread mill?
When you thread a hole on a standard milling machine, a tap will only use the machine’s Z axis to cut. A thread mill will use all 3 axes to cut the threads and use circular interpolation cycles to give the operator greater control over the cutting process.
What are Taps and Thread Mill Bits?
Indexable and solid thread mills can be made from carbide. Taps are available in a wider range of materials, such as high-speed steel, powdered metal, and sometimes carbide.
Thread mill tools only require one material because the circular interpolation method reduces the load. This creates side loads on the tool, which is preferred.
Taps are available in a variety of materials, mainly because the machine load is forced through the Z axis. This means that carbide taps are often too unstable, so a more compatible material is needed.
Why are Thread Mills Less Risky Than Taps?
When using a tap, the operator has no control over the cutting process. Typically using the G84 threading cycle, the operator cannot stop midway until the tapping cycle is complete. When thread milling is performed, the process can be better controlled.
Often, due to high loads, chip evacuation or poor hole conditions, the tap may break in the hole, resulting in the workpiece being scrapped. Or at least requiring an EDM to dissolve and remove the tap. Thread milling is a safer and more constant process, and it is certainly the preferred method for unmanned processing (green light processing) or expensive workpieces.
Large Diameter Thread Milling vs. Tapping
When we start talking about holes over 20mm, we usually talk about how the machine tool drives the tap. Taps can become very expensive to tap holes of this size. Thread milling not only reduces the cost per hole, but also reduces the chance of large taps breaking.
Since the cutting forces generated when thread milling are very low. They also greatly reduce the machine tool load compared to taps.
Thread Milling vs. Tapping
Which is Easier, Thread Milling or Tapping?
When threading in smaller diameter holes, both thread milling and tapping can produce threaded holes well without any damage to the machine tool. But when we talk about larger holes, the tapping forces increase dramatically. Thread milling, on the other hand, keeps loads low regardless of thread size.
How Does Thread Milling Compare to Tap Life?
In almost all cases, thread milling is more efficient and less loaded than tapping. You can apply a multi-pass strategy with a thread mill. If you are looking to reduce your cost per hole, a thread mill will generally be the preferred solution.
What is the Difference Between Re-threading with a Thread Mill and a Tap?
It is easy to re-thread with a thread mill if the part is still in the machine. The operator will adjust its offset compensation and restart the cycle. There is no risk of cross-threading or damaging the part. In almost all cases, threads produced with a tap must be re-threaded manually with an additional tap.
Which Produces More Accurate Threads?
Thread cutting end mills produce more accurate holes. Because you have 100% control over the diameter, the machine load is very stable. Not only that, the chips are cleared better, which will improve the surface quality. Using the same size tap and forcing the chips through the flute, the operator has no control over the chips.
Threaded end mills vs. taps are used to machine complex materials. For example, titanium, hardened steel, and nickel alloys. Thread mills really come into their own when it comes to cutting more difficult materials. With a tap, the tapping size increases, and the cutting forces increase, which can cause the tap to break. With a thread mill, you can control the cutting strategy to reduce the cutting forces, resulting in more consistent and higher quality threads.
Which is Faster, Thread Mmills or Taps?
On average, taps are faster, and taps only use the force of a single axis of the machine tool.
Advantages of thread mills vs. taps for machining small diameter threads.
When machining threads in smaller diameter holes, taps can easily get stuck. Especially in difficult materials such as stainless steel. This is due to the small diameter of the taps required, and the large loads they bear when tapping, which can cause broken taps to get stuck in the workpiece, resulting in the workpiece being scrapped. With a thread mill, you don’t have this problem. Because they are subjected to much lower cutting forces during machining, you have more control over it.
If a thread milling cutter breaks, the workpiece is not scrapped. You can replace the tool with a new one and continue working. Thread mills can also reach the bottom of blind holes because they don’t have a helix like a tap. This is a big advantage for short threads because they offer a full thread length that can be machined better than a tap.
For deep hole threads, such as 3x diameter, thread mills vs. taps have advantages When machining longer threads, multiple taps are required with the tap due to the load they are subject to when cutting. If this is not done, the taps often break. With a thread mill, you have full control over the entire process and can machine longer threads. This gives you process security and thread quality.
Tapping vs. Thread End Mill, Wow Do You Choose?
How do tapping and thread milling produce better quality threads?
Thread milling is a better process than tapping. The surface finish is better and the thread quality is better to the naked eye.
When to use a tap instead of a thread mill?
In most cases, a thread mill is the better choice due to the tool life it offers and the control it provides over the thread and finish. However, sometimes factors such as cost come into play, meaning it may not be the right choice for the job. Thread mills are more expensive than taps of the same size, and some processes may require additional costs, especially when processing small batch orders with small profit margins.
When should thread mills be used instead of machine taps?
Unlike taps, which are made to a specific size, thread mills provide the ability to produce a variety of threads. One pitch can be used to produce a variety of diameters, and you can simply adjust the diameter of the thread to produce fine threads than larger diameters, which saves the cost of purchasing multiple different tap sizes.
Imagine that you have a very expensive workpiece that has been put into many processes before it needs threading. In the end, the tap is selected, and it breaks on the part, causing the part to be scrapped. What a pity. Thread mills eliminate this risk.
