What's all this jargon about?

First up: Excavator vs Digger

Excavator = Digger
Same machine, different name. In New Zealand, "digger" is often the everyday term. "Excavator" is more common in manuals, brochures, and specifications.

Main parts of a digger (the stuff people point at)

Undercarriage
The bottom half of the machine - tracks, rollers, idlers, and the frame underneath. This is what the machine travels on.

Tracks
The "feet" of the excavator. Machines can have steel tracks (tougher, best for rough work) or rubber tracks (gentler on finished surfaces).

House (Upper structure)
Everything that sits on top of the undercarriage and rotates. This usually includes:

• cab

• counterweight

• engine

• fuel tank

• hydraulic tank

• pumps and valves

Cab
Where the operator sits and controls the machine.

Counterweight
The heavy weight at the back of the house. It balances the load when the boom is lifting or reaching.

Boom
The main arm attached to the house. It lifts and reaches out.

Stick (or Dipper Arm)
The smaller arm between the boom and the bucket. This is what extends your reach.

Bucket
The attachment most people think of first. Buckets come in different types for different jobs.

Quick hitch (or Quick coupler)
A device that lets you swap attachments quickly and safely without fighting pins all day.

Attachments: turning one digger into many machines

Attachment = Extra tools that connect to the digger
Attachments increase the number of jobs one machine can do.

Common examples you might hear:

• GP bucket (General Purpose bucket) - standard digging bucket

• Trenching bucket - narrow bucket for drains, services, and trenches

• Mud bucket / Cleanup bucket - wide bucket for shaping and finishing

• Tilt bucket - bucket that tilts side to side for neat battering and shaping

• Hydraulic breaker (Hammer) - for breaking concrete and rock

• Auger - drilling holes (fencing, piles, planting)

• Grapple - grabbing and handling logs, scrap, vegetation, demo material

• Ripper tooth - for tearing into hard ground or breaking roots

Swing, tailswing, and why it matters on tight sites

Swing
The space needed when the digger rotates. This is important near fences, buildings, live traffic, or other workers.

Tailswing
How far the rear of the machine swings out when rotating.

Zero tailswing (ZTS)
The back of the machine stays within the width of the tracks while swinging. Great for tight spaces, but not magic - you still need to think about the boom and attachments swinging around.

Working radius
The overall space the machine needs to operate safely, including attachment swing and counterweight movement.

Reach, depth, and height: the numbers you see in specs

These are common spec sheet measurements. They help you choose the right size machine for the job.

Digging depth
How far the bucket can reach down vertically. A simple way to picture it: park the machine at the edge of a riverbank and measure how deep it could dig straight down.

Digging reach (reach at ground level)
How far the boom and bucket can reach out horizontally along the ground.

Reach at full height
How far the machine can reach out when the boom is raised.

Digging height (Cutting height)
How high the boom and bucket can reach upwards.

Dump height
How high the bucket can lift and tip material out. This matters if you are loading trucks or bins.

Bucket breakout force
How much force the bucket can apply when digging into hard material.

Arm crowd force
The digging force generated by pulling the stick in. This also impacts how well a machine performs in tough ground.

Stability and lifting terms people use around site

Lifting capacity
How much the machine can safely lift at a particular reach and height. This changes depending on:

• boom position

• reach distance

• whether you are lifting over the side or over the front

• attachments fitted

• ground conditions

Over the side vs over the front
Digger lifting charts often show different capacities depending on direction. Over the front is usually more stable than over the side, but it depends on the machine.

Blade (if fitted)
Some excavators have a dozer blade. It can help with backfilling, levelling, and adding stability during lifting.

Safety acronyms you will see on machine specs

ROPS (Roll Over Protection Structure)
Designed to help protect the operator in a rollover event, when wearing a seatbelt.

TOPS (Tip Over Protection Structure)
Designed to help protect the operator if the machine tips over, when wearing a seatbelt.

FOPS (Falling Object Protection Structure)
Provides protection from falling objects (like rocks or debris). This is especially relevant in demolition, forestry, and quarry-type environments.

Quick note: these systems help reduce risk, but only work properly when operators use the machine correctly and wear the seatbelt.

Compaction terms you might hear

Sheep’s foot roller
A compaction roller with raised rectangular "feet". It is used to compact soil, especially silty clay, because the feet knead the material and push air out.

Drum roller (Smooth drum)
A smooth steel roller used for compacting gravel, basecourse, and asphalt.

Plate compactor (Whacker plate)
A smaller compaction machine used in tight areas like trenches and around footpaths.

Hire terms (this part trips people up all the time)

Wet hire
You hire the machine plus an operator (and sometimes fuel, depending on the agreement). Wet hire is ideal when you need the job done but do not have a qualified operator available.

Dry hire
You hire the machine only - no operator. You supply your own operator and usually manage fuel, transport, and responsibility for daily checks.

Tip: If you are unsure which one you need, think of it like this:

• Wet hire = "bring the skills too"

• Dry hire = "just the machine"

Bonus: a few extra common site words

Batter
A sloped cut on a bank (for stability and drainage).

Spoil
The excavated material you remove from a trench or hole.

Backfill
Putting material back into a trench or hole after work is done.

Services
Underground utilities like water, power, fibre, gas, and drainage.

Bench
A flat step cut into a slope for stability.

Got a word you keep hearing but do not understand?

Send your strange industry word (or photo of the machine part you mean) to marketing@prontohire.co.nz and we will explain it in plain English and add it to this list.