If you want a tougher hit from a jack hammer without giving up control, the YT27 is the right kind of upgrade. This Pneumatic jack hammer weighs 27 kg, measures 668 mm in overall length, and uses a big 80 mm cylinder with a 60 mm piston stroke to drive standard 22x108 mm tapered-hex steels. It runs in the 0.4-0.63 MPa working window and, at 0.63 MPa, delivers >=36.7 Hz impact frequency (about 2,200 blows/min) with >=75.5 J per blow. Feed it with a 25 mm inner-diameter air line, flush with a 13 mm water line, and you get steady penetration with clean holes and predictable handling. Use it on the air-leg for production, or as a hand held jack hammer for collaring and tight work.
Spec snapshot you will actually use
Weight: 27 kg; overall length: 668 mm
Cylinder: 80 mm; piston stroke: 60 mm
Operating air pressure: 0.4-0.63 MPa
Impact frequency at 0.63 MPa: >=36.7 Hz (~2200 blows/min)
Impact energy at 0.63 MPa: >=75.5 J per blow
Bit shank: 22x108 mm (tapered hex)
Inner diameter of air pipe: 25 mm
Inner diameter of water pipe: 13 mm
What these numbers mean underground
More punch per hit: the 80 mm cylinder and >=75.5 J impact energy at 0.63 MPa give the YT27 a heavier blow than the typical 24 kg class. That extra energy helps break tough, abrasive ground without bogging the steel.
Fast cycle rate: >=36.7 Hz at the top end keeps the bit landing on fresh rock, so the Pneumatic jack hammer stays cutting instead of polishing.
Stable handling: 27 kg with an air-leg takes the push-load off the operator, yet it is still manageable as a hand held jack hammer when space is tight.
Full-bore plumbing: the 25 mm air hose ID and 13 mm water line are not suggestions. Choking the air will starve the tool and flatten performance; undersized water lines risk poor flushing.
Setup and operating notes that save time
Pressure discipline: stay within 0.4-0.63 MPa at the drill. Many crews run mid-band around ~0.5 MPa for a balance of speed and wear. Verify pressure at the tool, not just at the compressor.
Hose choices matter: use 25 mm ID air and keep runs short and straight. Blow out the 25 mm hose and couplings before hookup; grit in lines will score valves and the 80 mm cylinder.
Water below air: keep water pressure below air pressure and use the full 13 mm line. It flushes cuttings without backflow that strips lubrication.
Start and stop cleanly: crack small air first, add water, then bring the Pneumatic jack hammer up to working pressure. On shutdown, close water first, then run light air a few seconds to dry internals.
Thrust and rotation: if rotation slows, back off the air-leg thrust slightly. Forcing it only risks a stuck steel. Keep flushing ports clear and the shank tail lightly oiled.
Customer questions and straight answers
Q1: Is the YT27 a hand held jack hammer or only an air-leg drill?
It is both. The YT27 is designed for air-leg production, but you can run it as a hand held jack hammer for collaring, squaring holes, or when you do not have room for the leg. At 27 kg, the air-leg will carry the load for longer holes.
Q2: What compressor setup do I need for this Pneumatic jack hammer?
Whatever compressor you choose, the important part is pressure at the tool. You need 0.4-0.63 MPa at the drill while flowing through a 25 mm air hose. Account for line length, fittings, and other air users so the YT27 still sees its target pressure during the cut.
Q3: Why does the YT27 use an 80 mm cylinder with a 60 mm stroke?
The 80 mm bore gives more piston area for higher blow energy, while the 60 mm stroke keeps the cycle quick. The result is >=75.5 J per blow with >=36.7 Hz impact rate at 0.63 MPa, which translates into strong, fast hits in hard rock.
Q4: What steels and bits does it take?
Standard tapered hex 22x108 mm shanks. That means your existing 22x108 tooling, couplings, and bits are typically compatible and easy to source.
Q5: Can I run it at 0.63 MPa all day for maximum speed?
You can stay within the 0.4-0.63 MPa spec. In practice, many operators sit around ~0.5 MPa to balance penetration and wear. Watch your results and parts life, then tune pressure accordingly.
Q6: How do I keep rotation lively and avoid stuck steels?
Maintain strong flushing via the 13 mm water line, keep water pressure below air, and control leg thrust so the steel keeps turning. If rotation stalls, ease off, clear the bit, and resume. Do not keep hammering on a stopped steel.
Q7: What maintenance matters day to day on this jack hammer?
Oil feed (inline lubricator), clean air (blow out the 25 mm hose), check hose couplings, inspect the shank tail, keep flushing ports open, and periodically snug long tie-bolts. Simple habits prevent costly downtime.
Q8: How does the YT27 compare to smaller hand held jack hammer models?
Expect more per-blow energy from the 80 mm cylinder and a quick cycle from the 60 mm stroke. That combination gives the YT27 a noticeable step up in breaking power while staying manageable with an air-leg.
Q9: Is it noisy or hard to handle compared to hydraulic rigs?
Any Pneumatic jack hammer is louder than a hydraulic rig, but the YT27’s air-leg support takes most of the push off the operator. Use proper PPE and keep hoses secured to manage whip and sound exposure.
Q10: What are the must-follow plumbing rules?
Use 25 mm ID air hose to the tool, 13 mm ID for water, and keep fittings clean. Undersized lines will choke the Pneumatic jack hammer and slow drilling more than any other simple mistake.
Why crews keep the YT27 in rotation
Spec that fits the work: 27 kg, 668 mm long, 80 mm cylinder, 60 mm stroke, 22x108 mm shank
Strong, fast blows: >=36.7 Hz and >=75.5 J at 0.63 MPa deliver confident penetration in tough ground
Simple and familiar: standard Pneumatic jack hammer layout, easy to service, tooling is widely available
In short The YT27 air leg rock drill is a straight-talking jack hammer that hits hard and stays reliable. At 27 kg and 668 mm long, with an 80 mm cylinder, 60 mm stroke, 22x108 mm shank, 0.4-0.63 MPa operating range, a 25 mm air line, and a 13 mm water line, it is built for real production. Treat it right, and this hand held jack hammer will reward you with clean collars, strong penetration, and fewer surprises. For teams who prefer a proven Pneumatic jack hammer over something finicky, the YT27 earns its keep.