Whether you call the non-ride-on versions of small trenchers and vibratory plows pedestrian, walk-behind or walk-along models, these versatile machines can save tremendously on manual labor and restoration costs when making a variety of in-ground installations. These installations can include short utility drops (gas, water, electric or cable), lawn-irrigation systems, sump-pump drain lines, decorative-lighting systems, antennae systems (like invisible fences) and, when using a wide trencher chain, footings for small storage sheds and landscaping projects.
Pedestrian trenchers and plows range widely in size and capacity, allowing you to rent a machine that's a good fit for your project, which may require squeezing the machine through backyard gates or dodging established landscaping. The Pow-R-Spade trencher, for example, made by The George Evans Corp., can cut up to 4 inches wide and 24 inches deep, yet weighs only 275 pounds and can be transported in the bed of a pickup truck or in a small van.
But at the large end of the spectrum are machines such as the Vermeer LM42 and Ditch Witch 410SX. The LM42, with 40 net horsepower and an operating weight of 3,335 pounds, can work effectively as either a trencher or a plow. The 410SX, with 34 net horsepower and weighing 3,310 pounds, is designated a plow, but is available with a front-mounted trencher attachment capable of cutting to 36 inches at widths to 6 inches.
It's probably safe to say that in the past, a pedestrian machine that could be fitted with a vibratory plow on one end and a chain trencher on the other was a better plow than a trencher. The trencher on these models usually was designed primarily to cut an initial entry slot that allowed the plow blade to begin working immediately at proper depth. More recent designs, though, have given the trencher end of these ambidextrous machines more power, allowing them in some instances to be used as dedicated trenchers.
Your choice between a plow or trencher, whether on the same machine or on a machine dedicated to one task, and your selection of a particular machine size, will depend on a number of considerations. Among them are the type of product to be installed, cover depth required, condition of the soil and obstacles on the site.
Depending on the size of a pedestrian plow, these machines typically allow cover depths from 6 to 24 inches, depending on soil conditions. Pedestrian trenchers normally provide deeper cuts, with maximum trench depths ranging between 30 and 48 inches. Maximum depth of cut for a given trencher, however, may depend on the cutting width, that is, as the cut is made wider, depth may decline.
The plow is an excellent tool to use when one of your primary concerns is minimizing damage to (and thus quickly restoring) the installation site. In operation, the plow's vibration mechanism oscillates its blade vertically some 1,500 times per minute, an action that neatly separates the ground in front of the blade and makes for fast, efficient installations. Large pedestrian plows may be capable of placing power lines and communications cable up to 1 inch in diameter, and gas and water pipe up to 3 inches in diameter.
If you're considering renting a pedestrian plow, be thoroughly familiar with the soil conditions in which you will be working. Vibratory plows work best in soils that are soft and moist. A plow may have difficulty working in hard, dry ground, and will likely break dry soil into chunks, requiring added restoration. If you're unsure about a plow's ability to work in a certain soil, discuss that concern with the rental dealer.
Soils that are hard and dry won't necessarily prevent the use of a vibratory plow, but a machine with more power probably will be required in these conditions. And, although the plow can't work in hard, solid rock, it will work reasonably well in conditions involving moderately sized surface or buried rock. If the rocks are not too large, the plow can either move them aside or break them up and move through them.
Of course, you want to make sure that the machine available will provide adequate cover depth for the product you're installing. Usually, a vibratory plow can be fitted with blades of varying length to suit the cover depth. A large pedestrian unit may, for example, be available with blade lengths of 12, 14, 18, 24 and 30 inches, and smaller machines may have an adjustable blade that provides a depth range from 6 to 12 inches.
Although specialty blades are available, for example, those used for cable-television lines, plow blades generally are classified as either feed-type or pull-type. The feed blade has a chute (sometimes removable) that automatically places the product being installed, such as cable, into the slot. Chutes have varying bend ratios to accommodate the differing flexibility of installed product, and the width of chutes may vary to accommodate different product thickness.
A cable reel attached to a vibratory plow using a feed blade can make your life easier by containing the cable in a safe, clean, compact space. Use of the reel is especially advantageous if laying the cable along the ground during installation would risk damage. Ask the rental dealer if a reel is available for the plow you're renting.
Pull-type blades typically are used to install product that is larger in diameter or that is too inflexible to pass through the chute. Pull blades, as their name implies, use a gripping device on their trailing edge to pull the product along during installation. Be careful when using a pull blade in particularly sticky soils, however, because the product could be damaged if it binds against the walls and stretches. If you're concerned about this possibility, better to use a trencher for creating a wider slot.
Chain-type, pedestrian trenchers typically provide cutting widths from 3 to 6 inches, and cutting depths to 48 inches. A few machines, however, may be available with extremely wide chains (one manufacturer offers widths to 16 inches). A general equipment-rental store may not stock small trenchers with extraordinarily wide chains, though, so if you need such a configuration, you may have to visit a trencher dealer, assuming the dealer has a rental fleet and the flexibility to modify machines for special applications.
If you intend to use a small trencher in difficult conditions, for example, in hard-packed or rocky soil, mention this to the rental dealer. The dealer may have machines set up for severe service with special chains and teeth. If not, the trencher dealer, again, may be a source for these special-application needs.
If your trenching job entails curved trenches, you may want to investigate machines with drive wheels that can be steered while digging. (Usually, of course, the trencher's wheels are locked together to provide the most power for in-line trenching.) But, on the other hand, most of these small machines are easy enough to maneuver through occasional gentle curves.
An accessory that you may find quite valuable on some trenching jobs is a horizontal-boring attachment. Although this attachment is not available for all small machines, it can be useful when a driveway or other such obstacle blocks the trench path.
Basically, machines equipped to handle a horizontal-boring attachment have a hydraulically driven power-take-off positioned low on one end of the machine. When a length of drill pipe with an attached cutting bit is threaded onto the PTO coupler, the PTO provides rotational force, and the machine itself (when moved forward) provides the required thrust on the bit. The drill string can't be steered, however, so shots under obstacles usually have to be fairly short.
Keep in mind, too, that large pedestrian trenchers (or plows) sometimes can be fitted at one end or the other with such attachments as a small backhoe, rock wheel or sod cutter. A large rental house might possibly have these kinds of tools available, and if demand is sufficient, may even have a machine set up for dedicated use as a saw or backhoe. But, again, the dealer may be the best source for these kinds of special tools.