DCD’s engineering project manager Chris wrote an article on selecting the best swivel for the job and now it’s been featured on Trenchless Technology’s website! Here’s an excerpt:
When selecting a swivel, it’s good to start with a review of its design features and the history of the swivel manufacturer. Some swivels on the market are relatively unchanged over the decades, while others incorporate changes, including the use of more modern seal materials and profiles. Main design features to consider include:
- Bearing configurations and fits specifically designed to absorb loads associated with HDD, including quality sourced spherical roller bearings designed for tensile load, long life and high reliability, and additional bearings designed to support bending loads
- A multi-stage sealing system intended for harsh environments that include drilling fluids such as bentonite
- A high, 5:1 safety factor that ensured a long life for all the mechanical parts
- Internal design features which protect seals from damage that could otherwise be caused by excessive grease pressure during greasing
These are all factors you should consider when selecting a swivel. With cost, like most products, you usually get what you pay for. “You can’t afford to buy cheap,” since poor quality products often will break earlier and end up costing more to replace in the long run. Look for swivels with high-quality bearings from well-established bearing manufacturers and the right type of bearing for the job such as one that will support some side load. And when it comes to bearings, size does matter. Don’t be fooled by swivels in smaller packages, because a reduction in size almost always means a reduction in capacity.
Also, when considering size, always buy a swivel that is rated higher than the machine you intend to use it on. Got a 30,000-lb rig? Get a 40,000-lb swivel. The difference in swivel price will be lost in the benefits you will derive. Here is a simple rule of thumb: Use a swivel at 10 percent above its rated capacity and you will decrease bearing life by 25 percent. Use a swivel at 10 percent below its rated capacity and you will increase bearing life by 40 percent.
Read more on Trenchless Online.