Drilling into Precision: Machining for Oil Rig Equipment - Impro Precision


Drilling into Precision: Machining for Oil Rig Equipment

March 19th, 2024

The goat head that’s installed on the top of a frac tree undergoes a lot of precision machining during its manufacture. As an essential element of a hydraulic fracturing Christmas tree, it provides the mounting locations for the valves that control fluid flows. It’s a good example of the kind of large, heavy-duty, machined parts required by and used in the oil and gas industry. If you need a precision machine shop capable of work like this, Impro can help.

Tough Alloys for a Demanding Environment

Nothing is treated with kid gloves on an oil rig or at a wellhead. Impacts and high loads are frequent, and the environment is dirty and wet, and often hot and corrosive. Carbon and stainless steel alloys are used extensively, along with specialized metals like copper-nickel and copper-nickel-tin.

Already hard and tough, these metals are often forged and heat treated. That makes them even stronger and more durable, but it also creates challenges for the machine shop tasked with turning, milling and drilling the forms needed.

Precision Machining

With alloys like those used in the oil and gas industry, precise, repeatable metal removal needs high horsepower, rigid structures and skilled CNC programming. Impro uses modern, well-maintained CNC turning centers and milling machines to achieve high accuracy and the short cycle times that control costs. In particular, workholding and cutting tools are set up to minimize the deflection that causes geometric errors and poor surface finishes.

Drilling is a particular challenge with these difficult alloys, and many of the parts used on oil rigs and other extraction equipment need a lot of holes. (The goat head is a prime example.) Most of this work can be done on CNC turning centers, which ensures a high level of concentricity with the part axis. Deep holes however, where the depth is more than 10 times the diameter, need special consideration.

The main problem is that drills can deflect when they protrude a long way from the chuck or collet. If the part surface isn’t flat, this can break the drill before it enters the body of the workpiece. Alternatively, if the drill deflects while in cut the hole will be inaccurate and again, the drill could break.

A second issue is chip removal, especially when the workpiece material is gummy and produces long, stringy chips. These can clog the drill, increasing temperature and causing size problems. There’s also a risk of the drill seizing and breaking. Prevention entails frequently withdrawing the drill (peck drilling), and supplying cutting fluid through the drill to the cutting region.

If a drill should break while in the hole, options are limited. It may be possible to burn out the stuck portion, or more likely, the workpiece may need to be scrapped and a new part machined. This is why most precision machine shops prefer to take drilling slowly.

Machined Oil and Gas Extraction Components

Parts precision machined for oil and gas applications include:

  • Sleeve valves
  • Split rings
  • Pipe couplings
  • Flow crosses and goat heads
  • Casing components
  • Drill bits
  • Flanges of various types
  • Components for master, wing and swab valves

Precision Machining for the Oil and Gas Industry

With extensive CNC resources and deep metal-cutting expertise, Impro can handle the most challenging precision machining jobs. We understand the special challenges posed by the parts used on oil rigs and elsewhere in the energy sector, and we have the skills and knowledge needed to achieve consistently high quality results. Contact us to discuss your precision machining needs.


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