Attachment answers / Hammers & breakers
What size hydraulic hammer do I need for my machine?
Short answer
Size the hammer to the carrier's operating weight first: roughly 350 J for a 1-4.5 t machine, 500-1,018 J for 4-7 t, 1,356 J for 6-10 t and 2,712 J for 10-15 t. Then confirm the machine's auxiliary flow and pressure meet the hammer's requirement.
Last reviewed August 2026 · Quarrymark Attachments sales engineering desk
A hydraulic breaker is the one attachment where getting the size wrong damages the machine rather than the attachment. It is worth ten minutes of arithmetic.
Carrier weight is the governing spec
A hammer works by driving a tool into material at high frequency. The reaction to every blow goes back up through the stick into the machine, and the machine's mass is what holds the tool down against that reaction. If the hammer is too large for the carrier, the reaction lifts the front of the machine instead of driving the tool. The tool loses contact, the piston strikes with nothing under it - blank firing - and the energy that should have gone into the rock goes into the hammer's own tie rods, bushings and the carrier's boom and stick welds instead.
That failure mode is not gradual. Cracked boom welds and elongated pin bores on a machine that has run an oversized breaker are a well-known repair, and they are expensive.
Undersizing has a cost too, just a cheaper one
A hammer too small for the carrier simply will not produce. It will bounce on hard material rather than penetrate, cycle times go up, and because it spends more time on the rock it wears tools faster. Nothing breaks, but you paid for a tool that does not do the job.
The band chart we actually build to
Every hammer we sell carries its carrier weight range in the product name, because that range is the specification. The table below is our own catalog, which spans 350 J on the smallest machines up to 2,712 J on a 10-15 t excavator.
Flow and pressure, which the energy figure hides
Impact energy in joules tells you how hard each blow is. It tells you nothing about whether your machine can drive the hammer. Every breaker specifies a required oil flow range in gallons or litres per minute and a working pressure. Too little flow and the hammer runs slowly and produces below its rated energy; too much flow and you over-speed the piston, overheat the oil and shorten the seal life dramatically.
Check three things on the machine before ordering: auxiliary circuit flow at working rpm, relief pressure setting, and whether the auxiliary line is plumbed as a one-way (hammer) circuit or a two-way (bidirectional) circuit. Many mini excavators ship with a bidirectional auxiliary for a thumb or a coupler and need a hammer line and a return-to-tank added.
Operating practice that decides the hammer's life
Keep the tool perpendicular to the material and keep down-pressure on it - the machine should be pushing the tool in, with the tracks just beginning to unload. Never pry with the tool; the tool is a chisel, not a lever, and prying snaps them. Do not run more than about 15-20 seconds in one spot: if the material has not broken, reposition. And grease the tool bushing on the interval in the manual, which on most breakers is far more often than operators expect.
| Impact energy | Carrier weight | Typical use |
|---|---|---|
| 350 J | 1-4.5 t | Mini excavators, post driving, light concrete |
| 500 J | 4-5 t | Mini excavators and backhoe loaders, footings, slab |
| 500 J (post driver) | 3-6.5 t | Post and pile driving, mini excavators and skid steers |
| 1,018 J | 4-7 t | Mini excavators, reinforced slab, small rock |
| 1,356 J | 6-10 t | Midi excavators, foundations, trenching in rock |
| 2,712 J | 10-15 t | Mid-size excavators, demolition, quarry secondary breaking |
Energy figures and carrier weight ranges are taken from the Quarrymark hydraulic hammer and post driver catalog. Confirm your machine's auxiliary flow and pressure against the hammer's data sheet before ordering.
What happens if I run a hammer that is too big?
The reaction from each blow lifts the machine rather than driving the tool, which causes blank firing. That transfers shock into the hammer's tie rods and into the carrier's boom, stick and pin bores. It is the most expensive attachment mistake you can make.
Do I need a dedicated hammer circuit?
Most breakers want a one-way circuit with a full-flow return to tank rather than through the machine's bidirectional auxiliary. Many machines need that line added, along with a hammer-specific relief setting.
Is a post driver the same as a breaker?
The mechanism is similar but the tool and the application differ - a post driver caps the post and drives it, with the energy managed for repeated driving rather than for penetrating rock. We list them separately for that reason.
