If you are shopping used Bandit hand-fed chippers, the 12XP and the 18XP are the two names you will keep landing on. They share Bandit's Slide Box Feed System and the same core hazards, but they are built for different jobs, and buying the wrong one is either overpaying for capacity you never use or stalling on wood the machine can't pull.
The core difference: capacity and feed force
The number in the name is roughly the chipping capacity, and it tracks the feed system's muscle. The 18XP drives its dual feed wheels at roughly 4,480 lbs of pulling power, well into full-size tree-service territory, behind a 37-inch-diameter, 22-inch-wide drum carrying four knives. The 12XP runs the same dual-wheel Slide Box concept in a smaller, lighter package sized for property maintenance and mid-size crews. More force is not free: it pulls bigger limbs faster, and it pulls anything caught with them harder, which raises the stakes on the safety systems below.
What to check on either, used
Both machines carry the same critical risk, and it is the one federal data says kills chipper operators: the feed system. On a used unit, the dual feed wheels, the reversing auto-feed control, and every emergency stop and feed-control bar must be tested in person before money changes hands, exactly per our federal safety-data guide (OSHA attributes 78% of chipper fatalities to being caught in the machine). A bypassed or sluggish feed control is a walk-away finding, not a discount.
The secondary wear differs by model. The 12XP's documented concern is its hydraulics: a 12-gallon tank drives both feed wheels and the auto-feed reversing control, and an undersized or neglected hydraulic system shows up as weak or erratic feeding. The 18XP's is the cutting head itself: the larger 37-inch four-knife drum is more expensive to maintain and re-knife, and it is the point-of-operation hazard behind the feed system.
The decision
- Property maintenance, mid-size crew, mostly limbs and brush? The 12XP. Do not overbuy feed force you will not use, and budget a hydraulic-system inspection into any used purchase.
- Full tree service, big daily volume, larger diameter? The 18XP. Confirm the drum and knife condition and price re-knifing before you buy, since the cutting head is the expensive half of this machine.
- Either way, test the feed and every e-stop first. The feed system is where these machines are dangerous and where used ones are most often compromised. That inspection matters more than the badge.
Full sourced record with risk detail: Bandit Intimidator 12XP. Safety framing and OSHA sourcing: what federal safety data says about wood chippers.