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Manual Post Drivers for 8- to 10-Foot-Long Metal Posts
The commercially available drivers cost from $173 to $270, fairly expensive compared to standard impact drivers, which typically cost from $20 to $80. The materials for the MTDC drivers cost about $24 with roughly 8 hours of shop labor needed to fabricate the PD–1 (slotted design) and 4 hours to fabricate the PD–2. The air-powered units listed in the manufacturers’ section cost from $450 to $1,750 without compressors.
MTDC tested the five manual post drivers by setting 10-foot-long, 1.33-pound-per-foot T-posts 2 feet into a clayey-loam soil that was mostly free of rock. The drivers all performed this task. However, it was somewhat awkward to load posts into the drivers and raise them into a vertical position for driving. The two Standard-Signs models have a short barrel length and stroke. This increases the operator’s tendency to push the driver off the top of the post on the upstroke, especially as the operator begins to tire. This could be a safety concern and potential source of injuries. It would be easy to lengthen the barrel, but doing so would increase the weight of the drivers by about 5 pounds. A longer stroke also would allow the operator to hit the top of the post with more force. T-posts fit loosely in the large barrel of the heavy-duty driver (NO8), making it awkward for the operator to stand and drive the post straight. The loose fit allows the handles to contact the post and might allow the operator’s hands to be injured. Both models lifted easily off the post after it was driven to the proper depth.The MTDC drivers are somewhat lighter and easier to handle than the Standard-Signs drivers. The small-diameter barrel keeps the handles away from the post while driving and helps hold the post vertical, allowing the post to be driven straighter. The longer barrel reduces the worry that the operator might lift the driver off the top of the post on the upstroke. However, the longer barrel requires lifting the driver higher when removing it from the post after installation.
At first, we were unable to load a T-post into the Post Mate because a spacer block designed to help hold the post in place was 1/8 inch too thick. After we ground a 1/8 -inch groove in the block, the post fit fine. Locking the 10-foot post to the driver proved to be awkward and was almost a two-person job, because the post must be oriented correctly and installed at an angle. Once the driver is locked to the post, getting the post and driver into the vertical position is easy.
The stroke of the Post Mate is only 14 inches, which makes it hard to apply enough force to the post. The upper section of the driver weighs just 21 pounds, also reducing the impact force. It took nearly twice as many blows to drive the post into the ground with the Post Mate as with the one-piece models. The Post Mate’s small-diameter handles were somewhat hard on the hands when driving posts. There is no chance of pulling the driver off the post while it is locked in place, an important safety feature. It also seemed easier to keep the post in a vertical position with the Post Mate because the point of impact is lower on the post.
The concept of pulling posts with the Post Mate sounds intriguing, but proved cumbersome. The short upward stroke and the weight of the handles made pulling the post difficult. Attaching the driver as low as possible and using leg muscles more than arm muscles helped.
All of the drivers can drive 10-foot-long T-posts. For driving many posts, the Standard-Signs Model NO4 with the modified, extended handles or the two MDTC drivers work well. The barrel of the NO4 driver could be lengthened 10 to 12 inches to increase the stroke length and to keep the driver from slipping off the top of the post. Doing so would increase the driver’s weight to 38 pounds. The NO8 is not well suited for steel T-posts, but may work well for U-channel, small diameter wooden posts, or tube-type posts that require a larger diameter tube and more impact weight.
The MTDC drivers are lighter than the other models tested, but with the longer stroke, they still do as good a job. The MTDC PD–1 tends to drag on the T-post studs, is more complicated to build, and offers no advantage over the MTDC PD–2. The MTDC PD–2 combines the best concepts of all the single-piece drivers tested, is inexpensive, and is easy to construct (see drawing).
![[drawing] Post driver design drawing](images/fig09.gif)
The Post Mate is a compact driver that can be used to drive and pull T-posts. This works well for driving just a few posts or for driving posts longer than 12 feet. It takes up less space and is easier to pack than other drivers, making it an attractive alternative for packing into the backcountry on horses or mules.
Standard-Signs.com (Standard-Signs
driver)
218 Rebecca Ln.
Normal, IL 61761
http://www.standard-signs.com/standard-signs/sigposdriv.html
Phone: 309–888–6677
Municipal Supply & Sign Co. (Standard-Signs driver listed as DH8
and DH4 manual post drivers)
1095 5th Ave. North
Naples, FL 34102
http://www.municipalsigns.com/post_d_p.html
Phone:
800–329–5366 or 941–262–4639
SCS Integrity & Service (Post Mate driver)
P.O. Box 913
1114 East
Marion Ave.
Nashville, GA 31639
http://www.scsincorporated.com/postmate.htm
Phone:
800–524–7567
Kencove Fence Supplies (Post Mate driver)
344 Kendall Rd.
Blairsville,
PA 15717-8707
http://www.kencove.com/postdriver.htm
Phone: 800–536–2683
Missoula Technology and Development Center (MTDC driver drawings)
5785
Hwy. 10 West
Missoula, MT 59808
/eng/t-d.php?link=dwf/nurseries
Phone:
406–329–3900
Rohrer Manufacturing
http://www.fencepostdriver.com
Phone: 800–438–7599,
code 03, or 541–548–7746
Rhino Tool Co.
http://www.rhinotool.com
Phone: 866–707–1808
Ovis Ram
http://www.ovisram.com
Phone: 417–890–5761
The author thanks Chuck Harding, MTDC, for helping design, develop, and fabricate the MTDC drivers. Thanks to personnel from the Beaverhead-Deerlodge National Forest’s Dillon and Phillipsburg Ranger Districts for their help in testing the new post driver. Thanks to MTDC’s publication and photography staffs for their help in putting this document together and to Deb Mucci for the design drawings.
Gary Kees is a project leader specializing in reforestation and nurseries projects at MTDC. He received his bachelor’s degree in mechanical engineering from the University of Idaho. Before coming to MTDC in 2002, he worked for Monsanto in Soda Springs, ID, as a mechanical/structural engineer and project manager.
For additional information, contact Gary Kees at MTDC
Phone: 406–829–6753
E-mail: gkees@fs.fed.us
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