Most used-chipper repair costs are a guess. Bearings, hydraulic motors, control boards: you find out what they cost when they break. Knives and anvils are different. They wear on a schedule, the parts have dealer prices, and you can budget them before you buy the machine.
Two numbers from our records anchor the whole thing. A knife edge runs roughly 25 working hours before it needs resharpening. And a full anvil set on a Vermeer BC700XL was quoted on camera at about $210 for the lower anvil and about $190 for the side anvil, so roughly $400 for the pair.
What 25 hours actually looks like
A chipper knife shears material against a fixed anvil. Every impact takes a little edge off. At roughly 25 working hours, a crew running eight-hour days is servicing knives every three to four days. A weekend operator gets a season out of the same edge. Same number, completely different ownership experience.
That is the useful translation. When someone tells you a machine "needs knives," ask what the hour meter says and do the division. If the meter reads low and the knives are gone, one of those two facts is lying.
The wear limits are published, and one is garbled
Morbark's own maintenance content, which applies across their brush-chipper line rather than to one model, gives hard discard rules rather than vague advice:
- A knife sharpened past the allowed wear limit gets discarded, not sharpened again. The exact dimension in that video is stated as "1 in" and the captions garble whether that is the wear-past figure or the remaining dimension. We are flagging it rather than publishing a number we cannot read cleanly.
- Two-sided knives can be rotated 180 degrees and reinstalled instead of replaced. Free second life, if your machine takes them.
- The knife holder is a wear part in its own right. Gouged more than 3/16 inch deep, it gets discarded.
- The knife clamp gets inspected and replaced if cracked or damaged, and the bolt threads get checked for wear.
The rule that costs people money sits on the M20R side of the same brand content: when you replace one knife, you replace all the knives on the drum. Not for tidiness. A mismatched set puts the drum out of rotational balance, and that imbalance loads the bearings and shaft every hour the machine runs. The cheap knife you kept is the expensive bearing you buy later.
The anvil is the part people skip
The anvil is the stationary edge the knives shear against. It wears slower than the knives, which is exactly why it gets ignored: nothing about a chipping session tells you the anvil is done.
The documented price we have is the BC700XL dealer quote: about $210 lower, about $190 side, roughly $400 for the set. That is one dealer, on one model, captured on camera. We have not sourced anvil prices for the Bandit or Morbark models in our records, and the open TODOs in those dossiers say so. Do not assume $400 travels to an 18 inch production machine.
The reason to spend it shows up in two independent places in our records. A companion Bandit service video is blunt that replacing knives without also servicing the anvil is what "prevents major damage and costly repairs" if you skip it. And Bandit's own official service video states that dull or severely damaged knives significantly reduce performance. Fresh knives against a worn anvil is half a repair.
There is also a safety item hiding in this job. On the 250XP, the anvil-side locking ring is not optional hardware. Bandit's service video is explicit: if the locking ring is missing, the retaining nut has to be replaced, because the ring is the locking device. A missing ring on a used machine is a question, not a shrug.
What $400 means against what the machine costs
Our observed BC700XL asking prices run $6,900 to $15,900 across sixteen listings, model years 2014 to 2022. The spread inside that band tracks region and dealer pricing at least as much as it tracks age or hours: one 2015 unit with 1,071 hours asked $9,900 while another 2015 with 102 hours asked $15,000.
So on the cheap end of that band, a full anvil set is roughly six percent of the purchase price. On the expensive end, closer to two and a half percent. Either way it is a rounding error against the machine and a real number against a week's revenue. Budget it. Do not be surprised by it.
What worn consumables tell you about the seller
Knife and anvil condition is the cheapest read you get on how a machine was operated, because it is the maintenance item that cannot be hidden by paint. Our records carry a long-running warning from arborist forum testimony: units with 5,000 plus hours still run daily, while the classic trap is the freshly repainted machine with a suspiciously low meter. Paint costs less than bearings.
Fresh knives and a fresh anvil on a high-hour machine is a good sign, not a suspicious one. It means somebody was still buying wear parts at the end. Dull knives on a low-hour machine is the combination worth asking about, because running dull means running with more feed pressure, and that pressure lands on the bearings and the drive system rather than on the wood.
That is the honest limit of what we can say here: it is a strong inference from operator behavior, not a measured relationship. We have no hours-to-failure data tying dull knives to bearing life, and we are not going to invent one.
The short version
Price a knife service every 25 working hours into your operating cost from day one. Carry the anvil set in the budget as a periodic item, at roughly $400 on a small Vermeer and unknown elsewhere until a dealer quotes you. Replace knives as a full set. Check the locking ring. Then read the wear parts on any machine you are shopping, using the full inspection order in our wear story guide, and price against the observed band in that model's record rather than the seller's confidence.