How to Buy a Used Anchor or Micropile Rig
Anchor and micropile rigs are bought for access as much as for capability. They work in basements, on slopes, inside existing structures and in places larger rigs cannot reach, and the dimensions that let them do that are often the deciding specification.
This guide covers matching a rig to its intended method and its intended sites, and what to inspect on a machine that has usually led a hard, confined life.
Start with the drilling method
Anchor and micropile work spans rotary, rotary percussive, duplex and self-drilling methods, and rigs are configured differently for each. Establish what the rig is set up for and what converting it would involve, because conversion is frequently possible and rarely cheap.
If the work involves rotary percussive drilling, confirm whether the hammer is top hammer or down-the-hole, and what air supply that assumes. A rig sold without the compressor it needs is an incomplete purchase.
Access dimensions are a specification, not a detail
Get the transport width, height and weight, and get the height in the lowest configuration the mast will fold to. Basement and low-headroom work lives or dies on this figure.
Check how the rig gets into position: tracked, on outriggers, or dismantled and reassembled. If your work involves confined sites, ask how long a typical setup takes and whether the machine has been doing that kind of work.
Consider exhaust and noise if the rig will work inside or under structures. Electric or dual-power machines command a premium for a reason and may be the only option for some sites.
Rotary head, feed and mast
The rotary head does the work and is the most expensive thing to put right. Ask when it was last overhauled, run it through its speed range, and listen for bearing noise and check for oil at the seals.
Check the feed system — chains, cylinders or rack and pinion depending on the machine — for wear and for smooth travel through the full stroke. A feed that snatches will cost you hole quality.
Inspect the mast and its mounting for the cracks and repairs that confined-site work produces. These machines get knocked, and a repaired mast is common; an undisclosed repaired mast is a negotiating point.
Hydraulics, tooling and rod handling
Confirm the hydraulic flow and pressure available and what that supports at the head. This is what limits drilling diameter and depth in practice, more than any headline figure.
Establish what tooling and rod handling is included. Rod handling arrangements vary widely and a rig without one is a rig that needs more people to run it.
Inspection checklist
- Drilling method confirmed, and conversion cost understood if it differs from yours
- Air supply confirmed if the rig drills rotary percussive
- Transport width, weight and minimum folded height recorded
- Setup arrangement and typical setup time established
- Emissions and noise suitability confirmed for enclosed sites
- Rotary head overhaul date established and the head run through its range
- Feed system checked for smooth travel over the full stroke
- Mast and mounting inspected for cracks and previous repairs
- Hydraulic flow and pressure confirmed against intended drilling diameter
- Tooling and rod handling confirmed in writing
Frequently asked questions
What is the most important specification on a micropile rig?
For most buyers it is the folded dimensions, because access is usually why a small rig is being bought at all. After that, the hydraulic flow and pressure available at the rotary head, which is what actually limits the diameter and depth the rig can drill.
Can a rig set up for one drilling method be converted to another?
Often yes, but rarely cheaply. Establish what the rig is currently configured for and get a real quote for conversion before treating it as equivalent to a rig already set up the way you need.
Do I need an electric rig for indoor work?
Not always, but exhaust and noise limits inside and beneath structures rule out diesel machines on many sites. If any meaningful share of your work is enclosed, an electric or dual-power rig is worth the premium.
Browse anchor & micropile rigs on Piling Broker or read the other buyer’s guides.