A few threads a day can be cut by hand or using a drill. The problem arises when a single component has a dozen or so holes, and production involves tens or hundreds of such components. In such circumstances, a tapping arm can significantly streamline the work.
Thread-cutting arm – when does it speed up production?
A few threads a day can be cut by hand or using a drill. The problem arises when a single component has a dozen or so holes, and production involves tens or hundreds of parts. In such circumstances, a threading arm can significantly streamline the process.
The device allows the tool to be quickly positioned over successive holes, reduces the operator’s effort and facilitates consistency when cutting internal threads. It offers the greatest benefits where the workpiece is large, heavy or requires many identical operations.
How does a tapping arm work?
A tapping arm consists of an articulated arm and a motorised head. The operator moves the head over the prepared hole, aligns the tap with the centreline and starts the cycle. Once the thread has been cut, the direction of rotation is reversed and the tool withdraws from the hole.
The head can then be quickly moved to the next position. This means the workpiece remains on the table, and the operator does not have to reposition a heavy plate, frame or structure under the machine spindle each time.
The electric tapper can be fitted with controls for adjusting operating parameters, including speed and direction of rotation. This allows the machine to be adapted to different thread diameters and the materials processed in the workshop.
Why does the arm speed up production?
During manual threading, the operator must control the tool’s positioning, rotate the tap and ensure it is guided correctly. With a large number of holes, this takes a long time and increases the risk of errors.
The tapping arm takes over a significant proportion of these tasks. The operator simply positions the head over the next hole and starts the cycle. The biggest difference is noticeable with plates, frames and structures featuring numerous holes.
In practice, this means shorter set-up times, less physical effort and easier organisation of the work. If the workpiece is large, moving the head is much more convenient than constantly repositioning the entire component under the drill’s spindle.
Greater repeatability of internal threads
When starting to tap by hand, it is easy to position the tool at a slight angle. This can impair the quality of the thread, increase cutting resistance and raise the risk of the tap breaking.
The arm helps to maintain the correct position of the tool relative to the workpiece surface. This is important in mass production, where successive internal threads should have similar quality and geometry.
This solution works well with steel plates, machine bodies, aluminium components, frames and welded structures. The repeatable tool guidance also facilitates quality control of finished parts.
How to select the rotational speed?
The appropriate rotational speed depends primarily on the tap’s diameter, the material of the workpiece and the type of tool. Smaller threads can be cut at higher speeds, whilst larger diameters usually require a lower speed and higher torque.
An electric tapper with variable speed control makes it easier to adjust the settings to suit a specific task. However, you should not select a machine based solely on its maximum threading range. If your workshop mainly produces M4–M12 threads, the most important factor will be smooth and stable operation within this specific range.
The choice of coolant or lubricant is also important. Adequate lubrication reduces friction, improves thread quality and can extend the service life of the tap.
A tapping arm or a drill?
A drill with a tapping function can be a good solution for smaller workpieces and occasional use. However, each hole must be aligned with the spindle axis, which, in the case of a large plate or heavy structure, requires frequent repositioning of the workpiece.
A tapping arm works the other way round – the workpiece remains in place whilst the operator moves the head. Therefore, for large workpieces and multiple holes, it can offer better ergonomics, shorter cycle times and greater working comfort.
The difference is particularly noticeable in mass production. If the workpiece to be machined has a dozen or several dozen holes, the rapid movement of the head to the next point reduces non-productive time and allows for better utilisation of the workstation.
When is it worth using an electric tapping machine?
It is worth considering a purchase when threading is a regular part of production. The greatest benefits are seen when:
- multiple threads in a single workpiece,
- short and medium-sized production runs,
- large workpieces that are difficult to move,
- frequent changes in thread diameter,
- the need to improve repeatability,
- reducing operator strain during batch production.
Where individual holes are drilled only occasionally, the machine may not always be necessary. However, if threading begins to limit the workstation’s productivity, automation can quickly improve work organisation.
Summary
A threading arm speeds up production, particularly when a large number of repetitive internal threads need to be cut. It facilitates tool setting, reduces the need for manual guidance of the tap and improves ergonomics when working with large workpieces.
A modern electric tapping machine allows for the adjustment of parameters, and a suitably selected rotational speed enables the operation to be adapted to the thread diameter and type of material. In workshops producing series of components, large plates and structures with multiple holes, a threading arm can reduce working time, improve repeatability and increase operator comfort.
