Spent the morning at the foundry, inspecting the cast-alloy clevis ends of the 350 ton and 500 ton swivels, and discussing the method with the foundrymen there. Sand casting has a long history, contributing to the Industrial Revolution and the automotive industry in its formative years – both pivotal events!
DCD Design takes advantage of the efficiency of sand casting to put metal where it’s needed, in the chemistry desired, to gain the properties necessary for the Maxi-DUB swivels to excel in the difficult conditions encountered in directional bore holes.
Castings are poured, chilled, broken out and individually inspected to ensure a quality product, but each casting is unique. The mold is broken every time!
Castings of this size (over 800lb, in some cases) will typically show the pattern of the sand, and perhaps the impression of the chilling blocks and part line. Overall though, the massive castings are homogeneous after heat treatment and benefit from the grain structure imparted by the process.
Dendritic growth and phase transformation are technical terms for it, but imagine ice crystals forming in a complex geometry.
Then imagine a massive, solid piece of alloy steel crystallizing like a snowflake. With some perspective, the old ways are damned impressive!
There’s a Maxi-DUB swivel leaving our Service Center this week, serial number 250-102. The first three digits are the tonnage – 250 tons. The second three digits are the production number – the second one made. (That pattern is standard for any of our big-rig swivels, btw.)
This swivel is something special: it was built in the fall of 1998, and delivered for service on the 12th of November that year. It’s probably the oldest Maxi-DUB swivel in service these days! *
We’ve seen it in for service three or four times over the 11 years since. When it came in this year for a routine service, I asked the mechanic to get a few photos, thinking I could write it up to show how regular maintenance will prolong the lifespan of the swivel.
I hadn’t expected it to be so banged up after a year in service! Still, the mechanic worked through it, cleaned it up, and replaced the necessary parts. It looked worse than it was.
Others have tried to duplicate the Maxi-DUB swivel but after years of service and hundreds of swivels, our patented design continues to prove itself. Other manufacturers can’t claim that.
* By the way, if you’ve got a record-breaker, let us know! Send us a photo and we’ll feature it here.
The Horizontal Directional Drilling Division of The Mears Group is one of the largest HDD contractors in the world. They’ve also got some great content on their website – check of their Media section for the Frontiers of Construction clip, featuring a DCD Maxi-DUB swivel being used for a river crossing.
Just past the halfway mark of the video, when they’re maneuvering the leading end of the pipe towards the drill string, you can see the swivel as they make the final connections to begin the pullback. That’s where DCD Design’s HDD swivels fit in: the drill string turns, the pipe does not.
An extra bonus: that river crossing is about 10 miles from DCD’s plant near Vancouver, Canada!
We wrote a piece for Trenchless Technology magazine a couple months back, offering some general advice on maintaining pullback swivels. This applies to any size swivel, from the DUB-Lite series up to the Maxi DUB-Swivels.
Pullback swivels for horizontal directional drilling (HDD) can be relatively easy to maintain if a simple preventative maintenance routine is adopted. On the job site, follow a simple clean-up procedure:
- At the end of each pull, continue rotation and hose down the swivel.
- Wash all the mud and dirt from the groove, until clean water runs out.
- Lubricate the groove to keep the seal cavity from drying out.
Check the swivel and its pins for wear. Clevis pins are designed specifically for this application and contribute to the strength of the swivel. Never substitute with unapproved parts!
Between jobs, keep your swivel clean. Protect it from the elements and keep it oiled. Always fit a thread protector to the API threads.
Pump a little grease into the swivel to ensure the bearings remain packed. On large swivels, grease will typically exit through a relief valve – review your owner’s manual. Make sure the valve is clear. Use only the factory recommended grease for your swivel.
If the swivel is starting to hitch or grind, it must be serviced immediately. We have service kits for many of our products, or a better option is to schedule a service between jobs at our factory authorized repair facility.
Don’t risk a job on a piece of equipment that’s not functioning smoothly. Invest in a little preventative maintenance and you’ll see the benefits.
You can read the full text in the May 2009 edition of Trenchless Technology magazine or on their website. Call or email us if you have questions about your swivel.
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