The thread, also known as the ‘flighting’, is the cutting and digging part of the manual post-hole auger. It is made of one or two spirals of metal around the central shaft and works like a screw.
The thread diameter, measured between the points furthest from the centre, determines what the size of the hole will be. Thread diameters are usually between 75mm (3″) and 150mm (6″).
The thread does not have sharpened edges but its thin blades can slice through the ground and pull the tool down into the ground like a corkscrew into a cork.
On some models, instead of a thread, the auger has a cutting plate which only circles the shaft once but uses the same principle as a thread to make a hole. This is an American design but is also sold in the UK. The soil has to be removed from the hole more frequently when using this design, in comparison to the threaded auger.
Tip of a manual post-hole auger
The tip – a spike below the thread – is the leading part of the manual post-hole auger. It makes the first cut into the ground and guides the thread after it.
Some tips have a small thread on them and are known as guide (or lead) screws. The guide screw is easier to screw into the ground than the large thread so eases the auger’s way downwards.
Shaft of a manual post-hole auger
The shaft joins the handle to the thread.
The length of the shaft and thread together defines how deep the hole can be. A 1m (3′) shaft (with thread) will mean the maximum depth of hole is just under 1m because that is how far the tool will reach into the ground and still be able to turn and function.
T-joint and eye of a manual post-hole auger
The T-joint is a separate metal part that joins the handle to the shaft.
Sometimes the handle is welded directly to the shaft and there isn’t a separate T-joint…
…but on most models the handle fits through the cross-piece or ‘eye’ of the T-joint.
Handle of a manual post-hole auger
The handle allows the user to turn the auger and dig into the ground.
The handle forms a ‘T’ shape with the shaft and is sometimes removable for easy storage or replacement of the handle. A T-shaped handle is referred to as a ‘T-handle,’ a ‘bar-handle,’ ‘tommy-bar handle’ or an ‘eye-handle.’
T-shaped handles that can slide through the eye in either direction can be used as ‘tommy-bar’ handles. You can use these handles to dig holes close to a wall or fence. The handle length can be shortened on the side of the wall, so that the tool can be turned past it, and then shortened on the other side as that reaches the wall.
On other models, removable handles are bolted in place to stop them slipping when the tool is being used.
Sometimes the handle has hand grips which make the manual post-hole auger easier to use and prevent a tommy-bar style handle slipping out of the T-joint while the tool is in use.
