TPT September 2020

T UBE WE LD I NG MACH I NE S & T E CHNOLOG Y

Beyond the basics – a new era of precise, portable pipe end bevelling techniques By Bill Atkinson, Tri Tool

MANY years ago the advent of portable machine tools specifically intended to provide weld prep bevelling on pipe ends ushered in an era of unprecedented welding precision that had previously been impossible with hand grinding. This was to be a critical advantage when orbital welding became widely implemented in many industries. Programmable orbital welding con- trollers required that pipe ends conform exactly to predetermined weld profile parameters in order to achieve efficient, repeatable orbital weld joints of certifiable quality. Portable bevellers enjoyed increased popularity with pipe fitters and welders, not only because they could perform rapid and easy bevels, but also because bevellers introduced two prime capabilities beyond accurate cutting. First, bevellers could perform complex weld preparation profiles such as compound bevels and ‘J' preps. Weld preparation profiles such as these are typically used to decrease the amount of filler metal and Heat Effected Zones (HAZ) that can both be an important consideration with heavier wall thicknesses. Secondly, portable bevelling machines can perform multiple pipe end cutting operations simultaneously, driving the cost of labour down and reducing the cycle times required that can be a major economic benefit when weld bevelling in a high production workflow. A good example of this is when a beveller has three tool bit holders and can perform simultaneous bevelling, facing and counterboring. Understanding exactly how a pipe beveller can perform several simultaneous cutting operations is key to realising what else can be accomplished with one of these versatile machines through reconfiguring with optional accessories. Many times, the machine name ‘beveller’ belies its full range of machining possibilities that, as we will discover, may permit the utility a reliability of this machine to provide a tremendous range of problem solving for diverse work requirements. In the simplest sense, a typical pipe beveller

The term ‘portable pipe beveller’ generally refers to any self-supported machine that mounts to a pipe utilising a secure clamp

is a geared mechanism that converts pneumatic, hydraulic or electrical power to a controlled rotary motion. A mounting plate, whereon one or more tooling holders can be attached, transfers that motion, providing a wide range of machining options. The term ‘portable pipe beveller’ generally refers to any self-supported machine that mounts to a pipe utilising a secure clamping means such as an expanding mandrel to both align the machine cantered in the pipe bore, and fully absorb the torque of the cutting operation. Portability can take the form of a handle on smaller machines up to lifting eyes for heavier machines designed to work with larger pipe sizes. Machine types have been developed to mount in the ID bore of a pipe, as well as machines that not only mount on a pipe’s OD surface, their frames can be split and reassembled around an in- line section of pipe. Whether mounting in the ID bore or a pipe’s OD, these machines achieve a secure rotating platform for the configuration of cutting attachments. In the conventional role (that the machine was most likely purchased for) a beveller provides tool holders that accurately position a form tooling bit that has the desired bevel angle pre-ground on its cutting edge. The beveller provides the ability to move

the tool holder position relative to the machine mounting, thereby permitting the operator to feed the bit(s) into the work piece until the desired cut depth is reached. You purchased a portable tool just for bevelling, but what other operations

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SEPTEMBER 2020