PMCColinet uses the customangle head on a Monarch VMC to produce keyways in the bore on oilfield pipe typically 6 inches in diameter and 12 inches long On one part PMC documented a savings of 184 hours in setup and machining time as the result of the head design supplied by Heimatec

Streamlining High-Precision Machining for Pipeline Parts

Jan. 31, 2014
Cutting keyways in oilfield pipe Nitriding steel Standard is too time consuming Unique angled head Cutting back hours

PMC-Colinet has a long history supplying production machinery to manufacturers of components for the pipe and tube market, having started in 1912 and introduced the world’s first carbide-tooled pipe threading machine in 1958.  Today, the company is established as a primary supplier of machines to the OCTG sector.   Its customers include integrated steel mills that sell finished pipe and couplings to the oil and gas industries, specifically using the those machines to produce threaded long products used in downhole drilling operations.  PMC-Colinet also supplies cutting tools, consumable tooling, aftermarket parts and field service to the industry. 

Recently, PMC-Colinet did an assessment on one very challenging job — cutting keyways into large sections on a high-precision cutting tool head made of Nitralloy® (a low-alloy VAC-ARC  grade, registered to Latrobe Specialty Metals.)  For many years, this sort of job had called for using a shaper to produce the keyway in the bore of the die head.  Typically, the bore ranged from 6 to 13 inches in diameter and more than 12 inches in length.  These keyways have extremely tight tolerances, with location at +/- 0.0005 in., width at +/- 0.001 in., and depth to +/- 0.0025 in. 

One style of cut is a three-step keyway that does not run all the way through the bore, stopping at a window that is milled from the outside diameter.  This situation prevented the PMC machining department from using a ram EDM to produce the keyway. 

One option tried previously had been to rough the keyway on an old shaping machine, then send it out for ram EDM.  This process required 50 hours on the shaper, plus approximately a week for the ram EDM.  Another option was to do the job entirely on the shaping machine.  Roughing the keyway had to be much more precise, and usually required about 61 hours to complete.  Normally, an additional 145 hours also were required to finish the part.  Added to these times were about 10-12 hours for setting up the machining processes. 

Toward a New Alternative

Led by milling foreman Rick Kokish, the team at PMC decided to explore other methods to produce this part on its Monarch 175B VMC.  They conducted an exhaustive search on the Internet, turning up over 133,000 hits for 90º angle heads.  After more than 30 hours of gleaning out the unsuitable products, they narrowed the search to just two vendors.  Both manufacturers visited the facility and brought out their standard angle head designs.   One of the companies, Heimatec, quickly realized this job would require a custom 90º head design to satisfy all the requirements. 

Heimatec designed this special 90º angle head (16 in. long) for cutting the keyway in a high-precision cutting tool head used in oil-and-gas drilling operations.

Heimatec designs and produces tooling for manufacturers worldwide. In 2010, it established an operation near Chicago to supply its North American customers, who operate in the automotive, aerospace, medical, off-highway, rail, energy, woodworking, composites and other industrial supply chains. 

In the bid to supply PMC-Colinet, one other tooling supplier brought a standard 40-taper tool for consideration, while Heimatec presented a larger, heavier 50-taper unit.

A week later, Heimatec’s president Preben Hansen supplied a drawing for the custom-designed product his organization proposed.  PMC’s engineering team reviewed both the standard and custom designs, and awarded the project to Heimatec.

The angle head supplied was designed to perform a wide variety of cutting tasks on the various end products that PMC produces.  On the keyway in a bore 6 inches in diameter and 12 inches long, using the Heimatec 90º head, PMC spent six hours in setting up the process, three hours for roughing and three more for finishing — plus 12 to 16 hours of actual cutting time.  This represented a total savings of 184 hours on a single part.  Though the head seem at first glance to be too slender to remain rigid during the entire cutting cycle, according to PMC sources, the performance was very successful.  

Heimatec’s head design for this custom radial drilling and milling head features an adjustable tool stop, three support pins for stabilizing the tool, CAT 50 taper style, 360º indexable pivot on the angle head, and inclined tooth gear design for maximum rigidity. 

During the project, Preben Hansen supervised the installation.  After the stop block attachment and grinding of the supports pins for the head were accomplished in just one day, the head was mounted and several experimental cuts were performed.  Hansen spent time with Rick Kokish as well as CNC programmer Barry Spence at PMC, discussing various options for programming the head on the Monarch VMC.  The very next morning, the setup was performed and an actual keyway was roughed. 

The results for ongoing production of the pipe product have continued to satisfy all requirements, according to PMC sources.

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