November 2018 – Sponsored by Kubota
By – Tim Nephew
I had a list of projects that I wanted to tackle on our property. I wanted to place an eight foot deer fence around my vineyard, there were trees that needed planting and a post frame building that I hoped would someday be a reality. The one thing in common with all of the projects is that they would require digging a lot of post holes. Having experienced the work involved with digging post holes by hand for some smaller jobs, I decided to look at the benefits of adding a tractor mounted post-hole digger to my tractor. Here is some basic information about post-hole diggers that you may find useful.
How it Works
The tractor mounted post-hole digger consists of an auger for boring in the ground, a boom that attaches to the auger, a yoke that supports the boom and a Power Take Off (PTO) shaft that attaches to the tractor’s PTO for power. It attaches to the tractor via the three point connections standard on a Category 1 or 2 system. There are models designed for every size of tractor from sub-compact to high horse powered tractors. Prices for tractor mounted post-hole diggers start at around $400 but can range over $1000 depending on size and model.
One of the benefits of using a tractor mounted post-hole digger is that they are easily moved to the job location and subsequent digging spots by the tractor. The three point connection allows for proper vertical placement of the post-hole digger. Also, available on some models, is a positioning handle attachment that allows the operator to move the tip of the auger directly from the tractor seat allowing for greater accuracy and safety. Once the auger is in the proper position, power from the tractor’s PTO is transferred to the gearbox on the post-hole digger which in turn supplies the power to the auger for boring into the ground.
There are also optional Down Pressure Kits that can be added to the tractor if you have heavy duty digging applications or your soil is compacted or rocky. These kits require using the hydraulics from your tractor to exert up to 500 pounds of additional downward pressure on the three point hitch arms.
These kits usually contain hydraulic cylinders and the additional hardware and hoses to mount to the tractor. It is important to find out if your tractor has the available hydraulics to supply the kit and if your tractor can support the additional structural stresses produced by the kit. Pricing is specific to the post-hole digger model and tractor pairing and most require a consultation call to the manufacturer to attain prices.
Another helpful option offered by most post-hole digger manufacturers is a Park Kit. These kits bolt to the post-hole digger and allow for one person mounting and removal of the digger. The Park Kit also provides a better storage option and keeps the unit off of the ground when not in use. They are usually model specific but generic units can be purchased to fit most models. Expect to pay anywhere from $90 and up depending on model and make.
When purchasing a post-hole digger, it’s important to note that the augers are usually priced separately. The auger on the post-hole digger is subjected to some very hard wear and tear and purchasing a high quality auger is a good investment. When purchasing an auger, there are several models and types that you will need to consider. Not only do they come in a variety of sizes based on the diameter of the hole, but there are also specialty augers depending on the type of work you are doing.
Augers may be purchased in sizes ranging from six inches all the way up to 36 inches, with a length averaging about 48 inches. There are augers designed specifically for dirt, planting trees or working in rock. Prices start at around $100 but can go up to $400 or much higher depending on the type.
The most common auger is the dirt auger that will usually handle most of the typical digging jobs. Some companies offer specialty tips that may be changed out on the auger depending on the type of soil you may encounter. A quality auger will be made of superior materials which will increase the cost of the auger but will handle years of hard use.
Tree augers are typically used for planting larger trees and used by orchards or landscape professionals. They may also be purchased in a variety of sizes and are somewhat unique in that the auger shaft is larger at the top and smaller at the bottom. This design helps to accommodate the root ball and allows for greater nutrient absorption.
Rock augers are also more of a specialty auger and as such their price can increase dramatically. If your soil is rocky or severely compacted, or if the ground is in an almost frozen condition, rock augers may be your only alternative. Heavy shaft construction coupled with carbide tips on the auger point enable working in these extreme conditions. As mentioned before, rock augers can be extremely expensive depending on the application.
Using the Post-Hole Digger
Using a post-hole digger for the first time can seem a little daunting, but most manufactures provide an Operators Manual that will serve as a good reference. Before starting any digging job, make sure the area is safe from any underground utilities. Once you are ready to start, mark or plot out where you will be digging the holes before you start to work. This will save you time and allow you to stay on the tractor and move to the next hole.
Drive the tractor to the location of the first hole to be drilled and if possible position the tractor on the upside of the hill to increase stability and downward leverage. Use the three point hitch and leveling arm to make the digger vertical to the hole and lower the point of the auger until it just touches the ground and engage the PTO. As you continue to drill down, run at higher speeds in light or sandy soil and slower speeds when digging in rocky or frozen soil. When you have reached the desired depth of the hole, keep the PTO engaged until you remove the auger from the hole.
As with any tractor attachment, it is important to practice good safety habits when using the post-hole digger. According to the Ohio State University Extension Service, (https://ohioline.osu.edu), the three most common injuries caused by post-hole diggers include entanglement of the PTO, entanglement with the rotating auger and injury to bystanders by objects being thrown from the rotating auger. The website goes on to offer the following safety tips:
Read and understand the owner’s manual and safety labels before using equipment.
Make sure all equipment shields and guards are in place and are in good condition.
Inspect the digger before each use to ensure it is in good working order.
Check for fluid leaks of hydraulic lines or the gearbox and repair before use.
Relieve pressure from the hydraulic system before repairing, adjusting or disconnection a hydraulic driven post-hole digger.
Use only the shear bolts or auger retaining bolts supplied/specified by the manufacture.