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DCD Design is making arrangements to open a new warehouse in the Midwest, to provide immediate support to our customers when they need it – “NOW!”
We’ll be just an overnight shipment away for many of our most popular tools, including line stringing swivels, underground duct pullers, threaded innerduct “carrots” and DUB-Lite swivels for horizontal directional drilling / boring.
Look for more details in the coming weeks, and be ready to take advantage of our quick turn-around, moving even faster!
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.
I had a customer ask how long a swivel will last in an unusual application, and I had to sit down and think about how to provide an answer that made sense. In short, the answer is “It depends!”
It depends entirely on how the swivel is maintained and the conditions it’s working in. The bearing manufacturers have a standard calculation that I use to assess a bearing lifespan, comparing the actual applied load to the bearing’s rated load. (Bearings are defined by their Basic Life Rating: the maximum load they can carry at a constant speed so that 90% of a representative sample will reach one million revolutions.)
At the Safe Working Load and standard conditions, a swivel’s bearing will last for 1 million revolutions, for example. At one-half the SWL, it will last significantly longer, 8 million revolutions. Both these calculations presume the swivel and grease are not compromised.
In short, the harder you work a swivel, the shorter the lifespan – and the relationship is not linear! Look at the above comparison: one-half the load leads to eight times the revolutions.
The load on the swivel is one factor. The care and maintenance you provide for the equipment is another major factor.
To last for 8 million revolutions, the swivel and its bearing will need lubrication at regular intervals. Since the frequency of maintenance will directly affect the level of reliability, we recommend lubrication after every pullback to keep the grease in the best possible condition. (And a thorough cleaning besides!)
In other news: we’ve had requests for a lengthened version of the Plow Grip Flip video, to fully illustrate the parts order when rebuilding after maintenance. I’ll take a crack at that when we get back from next week’s ICUEE show in Kentucky.
And if there’s anything else you’d like to see, let us know! We’ve got a few ideas for new videos, but I’m sure we could get yours on the list.
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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