About Amerisurv| Contact    
Magazine | Newsletter    
Flickr Photos | Advertise    
HomeNewsNewsletterAmerisurv DirectoryJobsStoreAuthorsHistoryArchivesBlogVideosEvents

Sponsored By

Software Reviews
Continuing Series
An RTN expert provides everything you need to know about network-corrected real-time GNSS observations.
Click Here to begin the series,
or view the Article PDF's Here
76-PageFlip Compilation
of the entire series
Test Yourself

Got Answers?
Test your knowledge with NCEES-level questions.
  Start HERE
Meet the Authors
Check out our fine lineup of writers. Each an expert in his or her field.
Wow Factor
Sponsored By

Product Reviews
Partner Sites







Spatial Media LLC properties




Home arrow Archives   The American Surveyor     

Product Review: SECO Poles and Prisms Print E-mail
Written by Al Pepling, LS   
Friday, 29 August 2008

A 341Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

Tired of prism pole slippage and non-adjustable prism pole bubble levels? Tired of tilting prism target assemblies that slip as you are walking back to the instrument or having to lift the prism pole out of the bipod ring, or not being able to adjust the "spring" out of your setup and finding it has gone out of level by the time you are done turning your traverse angles and collecting your side shots? SECO has newer products that will solve these problems and allow you to work more efficiently.

Mike Dahl, VP of SECO asked me to try out the products over time and provide feedback to SECO during their use. You can bet I was happy to comply with their request.

Years ago, compression locking prism poles were the first type I used. They held well initially, but would start to slip if the threads were not kept clean and well lubricated. They tended to wear quickly, especially if made of softer brass. One manufacturer had a handle/ grip that you compressed to set the pole height and then released it. After months of use these could slip too. When the multi-sectioned prism poles with the plastic lever clamps came on the scene, I was still using the older model. Finally I updated to the plastic lever clamps. On a topo, a slippage in the prism height is not a significant issue, but when setting steel for a multi-story building, or for bridge construction, or when trig-leveling for control, it is an issue.

My unscientific test was to set the prism height and then exert downward force on the top of the sliding prism pole. Unhappily, all of the above could be made to slip with enough downward pressure. The plastic clamping models seemed to wear and slip the easiest. A rough rod handler also contributed to rod slippage.

SECO has a wide variety of prism poles and locking mechanisms. Now they have produced a prism pole with their QLVTM (Quick Lever with Vial) locking mechanism, and so far it has not slipped one iota during use. I repeated my unscientific test with the QLV and ceased my downward pressure when I became concerned that the pole itself would bend. (I left a divot in the bituminous pavement.)

It operates with less than a 45-degree lever movement with no apparent drag when unlocked and positive locking when engaged (Figure 1). Even better is that it is "field" adjustable or serviceable and you can vary the locking pressure to suit your taste. An Allen wrench is all that is necessary.

The "high-vis" 40-minute vial (Figure 2) is a part of the QLV. I particularly liked its design with the adjusting screws on the top. (There are additional models available as well). A small item, but a definite contributor to the quality of the whole assembly is the brass locking nut. Our junk box at work has a couple of the plastic variety and some plastic clamps in it.

My assessment is that the QLV prism poles will eliminate some sources of systematic errors and blunders over the long hall. Like any quality purchase, it has the potential to provide a great return on your investment.

The next part of the system is the Rear Locking 62mm Premier Prism Assembly with 6 x 9 in. target plate. The plate, yoke, and target mount are made of metal, a generally more robust material than those made of plastic. There are two notable improvements in my opinion. First is the target plate itself. The target pattern greatly aids in aiming the gun and is available in several colors. There is a small hole in the plate that aids in aiming the target at the instrument.

The second is actually in two parts. One is the slot with a socket head cap screw to provide very fine adjustment to the ease with which the target can be tilted. The second is the locking lever to prohibit movement once you aim the prism/plate assembly at the instrument (Figure 3). Prism pole or tripod, tribrach, and tribrach adapter, this target assembly is very aptly named!

The final component of this trio of products is the smart Quick Lever Bipod with Thumb Release Legs (Figure 4). Quick is definitely the operative word!

By the third setup I learned that I could reduce the amount of spring back tension in my setups by leaving the lever unlocked, planting the bipod legs in the ground and then plumbing up the prism pole, and finally locking the lever cam (Figure 5). The Delrin locking mechanism has an 80-durometer EPDM plug and won't mar, scratch or crush your pole. These are much faster to set up than my old style rings with the fine threads bipods.

My initial reactions are of the quality and speed of these components. The materials speak to longevity and reduction of systematic errors with less effort than I presently employ. Longevity-- my present bipods are SECO's older ring types with the little sprung levers on the clamping assembly that are so much more difficult to level up than the thumb press types now used, and I've had them in use for 15 or so years with minimal maintenance.

As to cost, you have to balance it against improved setup time and the potential for reducing systematic error. This reminds me of a sign I once saw in a shop, "The bitterness of poor quality lasts long after the sweetness of low price is gone!" You have to ask yourself: What is my reputation worth?

Al Pepling practices surveying with CWM Environmental in Kittanning, Pennsylvania. He is licensed as a Professional Land Surveyor in PA, past president of the New Jersey Society of Professional Land Surveyors, and held a Professional Planners license when residing in New Jersey.

A 341Kb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

< Prev   Next >

Marc Cheves, PS 
Editorial: A Great Year to be a Surveyor
Some magazines have what are called "theme" issues. That is, most of the content is focused on one particular subject. In my 22+ years of survey magazine publishing, my philosophy has always been to have a little bit of everything in each issue, thereby eliminating the possibility that ....
Read the Article
Jason E. Foose, PS 
Decided Guidance: Case Examinations: Halverson v. Deerwood Village
Whew! We really beat the snot out of Bryant v. Blevins and practical locations. Well this month we're back on new case that hit the Minnesota Supreme Court's docket in 1982. We've got the familiar gymnastics of jurisprudence featuring an extraordinary array of flying rope stretchers ...
Read the Article
Michel Philips 
Extreme Environment Surveying
A Franco-Chilean team of cave divers used the Nautiz X8 rugged handheld for marine cave surveying, gathering data to classify the inaccessible northern half of Madre de Dios for UNESCO World Heritage. The team of cave divers used the Nautiz X8 ....
Read the Article
Erik Dahlberg 
The Original Green Engineers
Sometimes, it's best just to leave things as you found them. That's the lesson shared by Dr. Richard Miksad and his students at the University of Virginia. As a result of studies covering nearly a decade, Miksad's teams have developed detailed ....
Read the Article
Dave Lindell, PS 
Test Yourself 49: No Dimensions
In square A-C-D-B with side S, C-E is tangent to the semicircle Q1 with diameter B-D. Q2 is the inscribed circle of A-C-E. The tangent to Q1 and Q2 meets the sides of the square at F and H and intersects C-E at t G. Q3 is the inscribed circle of C-G-H. What is the ratio of the radii of circles ....
Read the Article
Jerry Penry, PS 
Discovery on Grizzly Peak
When First Lieutenant Montgomery M. Macomb arrived in Carson City, Nevada, from Washington D.C., on July 28, 1878, his assigned survey crew from the 4th Artillery was waiting and ready for the new field season. At age 25, Macomb was the leader ....
Read the Article
Wendy Lathrop, PS, CFM 
Vantage Point: Fighting City Hall Over Land
Once upon a time (1989 to be exact) in a place not so far away from where I live, a man (Francis Galdo) bought a home across the street from a vacant parcel owned by the City of Philadelphia. That parcel, along with others, had been acquired by condemnation back in 1974 subsequent to a 1956 ....
Read the Article
Patrick C. Garner, PS 
Book Review: Boundary Retracement: Processes and Procedures
When I was in my mid-twenties and learning the honorable profession of land surveying, I was lucky to be guided by a mentor who would grab a book off his office shelf and say, "Every surveyor should have a copy of this!" The first example he waved at me was Davis, Foote and Kelly's Surveying ....
Read the Article


Amerisurv Exclusive Online-only Article ticker
Featured Amerisurv Events
List Your Event Here
contact Amerisurv


SXblue Announces
Premier Receiver

press [at] amerisurv.com
Online Internet Content


News Feeds

Subscribe to Amerisurv news & updates via RSS or get our Feedburn
xml feed

Need Help? See this RSS Tutorial

Historic Maps

post a job
Reach our audience of Professional land surveyors and Geo-Technology professionals with your GeoJobs career ad. Feel free to contact us if you need additional information.


Social Bookmarks

Amerisurv on Facebook 

Amerisurv LinkedIn Group 

Amerisurv Flickr Photos 

Amerisurv videos on YouTube 



The American Surveyor © All rights reserved / Privacy Statement
Spatial Media LLC
7820B Wormans Mill Road, #236
Frederick MD 21701
301-695-1538 - fax