As any seasoned welder knows, a clean, smooth surface greatly reduces costly rework of the weld joint and, therefore, saves a considerable amount of time. With that in mind, quality weld preparation is just as important – if not more – than the weld itself.
Today, two major techniques are used for edge beveling and welding preparation: large semi-stationary machines and angle grinders. The former creates very precise, clean angles at various bevel depths. And while they are strongly favored in pipeline construction, they are costly in terms of investment and operating expenses and aren’t very adaptable to varying applications.
Angle grinders, on the other hand, are probably the most versatile solution, giving access to the smallest corners and allowing various angles and shapes. Depending on the experience of the operator, however, they can lack the necessary precision for the required angle and depth. Grinding also results in a “hot” processing, potentially altering the properties of the metal and creating a hazard from the metal fines and abrasive sparks that are created in the process.
What’s truly needed in the field, therefore, is a tool that merges the main benefits of the two major techniques: precision and versatility. Metabo, a handheld tool manufacturer, did just that with its new line of beveling tools.
Basically, anyone who has to prepare metal surfaces for welding could be considered a targeted user for the new line of beveling solutions. Of course, pipefitters and the pipeline industry are a key target as their work is always custom and requires precision. Additionally, welds are always inspected, sometimes with advanced methods such as X-ray or ultrasound.
In the shipyard industry, the new tools are also a popular solution, not only for welding but also for coating preparation. According to international standards, every exposed edge needs to be prepared with a 1/8-in. (3-mm) radius to ensure proper adherence and thickness of the coating material such as paint or epoxy. The cordless model KFM 18 LTX 3 RF allows for work where power may not be available – a common issue in shipyards. It also offers more than 100 ft. of radius cutting on a single charge, which is key for working on large structures such as ships. The single-charge capacity is possible thanks to the company’s latest 18-V, 7.0-Ah lithium high-density batteries.
No matter the application, the tools are also being sought after by business owners that place worker safety above all else. This is because the tools use the best-in-class safety technologies inherited from Metabo’s angle grinder.
The patented mechanical safety brake in the KFMPB 15-10 F stops the cutting head in less than 1 sec., significantly reducing the risk of injury in the event of an operator losing control of the tool. Additionally, the complete range of beveling tools are equipped with a full electronic package that includes overload protection, restart protection (preventing the tool from restarting on its own in the event of a power interruption), speed stabilization and safety shutdown.
Overall, when compared to edge preparation using an angle grinder, the beveling tools cut costs by decreasing processing times by up to five times. The labor cost savings from less rework and improved weld quality quickly offset the higher acquisition cost of the beveling tools.
Best of both
Tackling the capabilities of large semi-stationary machines and angle grinders, the new beveling tools offer the best of both worlds. They offer unlimited versatility while allowing for a precise and clean cold processing of the metal. They also offer a strong and long-lasting motor. After three years of deep field research, Metabo designed the tools using the company’s patented LongLife motor.
The company’s research also resulted in a custom cutting head that uses indexable carbide inserts. Using the patented “one touch” controller, the depth of the cut can be precisely adjusted by 0.004-in. increments. The tool-free mechanism also guarantees jam-free operation.
The cutting head consists of two or three (depending on model) indexable cutters that can be quickly rotated once they wear out. The square cutters can be rotated four times, which allows for long life in an economical fashion. Most other products require operators to change the entire cutting head, which proves to be very costly.
With the cold cutting indexable cutters, there is no heat transferred to the material, meaning the groove face and the material in general are not affected by heat deformation, and the integrity of the material’s performance is not compromised. This technology makes the tools particularly effective for processing stainless steels and other heat sensitive alloys with the use of special cutting inserts.
Two classes of tools are offered. Metabo’s compact tools, available as corded and cordless, are designed for internal and external chamfering, edge preparations and radius cutting. The KFM 9-3 RF and KFM 18 LTX 3 RF bevel or chamfer up to 1/4 in. depth at 45 degrees and include indexable cutters for 5/64 in. (2 mm) or 1/8 in. (3 mm) radii. The larger options, including the KFM 15-10 F, KFMPB 15-10 F and KFM 16-15 F, offer unlimited bevel angle customization from 0 degrees to 90 degrees with a maximum depth of up to 5/8 in. at 45 degrees (or 1 1/4 in. at 12.5 degrees).
One of the key added values of the larger solutions is the ability to easily change the cutting angle without having to invest in additional costly cutting heads. This is particularly important when preparing a double-K bevel with a 60-degree groove (30-degree bevel) on one side and a 45-degree groove on the other side. The Metabo solution works regardless of the depth and the angle using the same indexable cutters, making it cost-effective. Plus, this eliminates the risk of having to replace shattered cutting heads that cost hundreds of dollars.
Another advantage is that the same tool can be used on both plates and pipes as small as 2 in. dia. with an integrated roller guide attachment. For welders who do custom work and need to adapt to multiple requirements on a job, it’s a smart choice. And, with its precise depth adjustment (increments of 0.1 mm/0.004 in.), any bevel depth, root joint or groove face size can be accomplished.