A story about a new combine-mounted weed crusher in the British farm magazine Farmer's Weekly (www.fwi.co.uk) recently caught our eye.

It was built by farmer Kevin Buckland, in Gloucestershire, England, who's been working on the idea since 2012.  It does the job of the Harrington Seed Destructor "the Australian invention that fits on the tail end of a combine to grind down weed seeds harvested with small grain crops before returning them to the field " but at a fraction of the cost.

Buckland works for a large organic farm operation where yields have dropped by more than half in recent years due to yield-sapping damage caused by hard-to-kill weeds.

So Buckland devised a "pin mill" system that consists of two sets of discs fitted with extended 3-in. bolts.  One disc of each pair spins while the other is static.  Seeds are crushed between the discs before they're thrown out the back of the combine together with the chaff.  There are 3 rings of bolts on the rotating discs and 2 rings on the static side.  

Each "pin sandwich" is wrapped in tin to form walls around the discs.  Three flexible tines on each set of discs keeps crop material from bridging between the discs. The tines, taken off a mower-conditioner, spin with the top plate, constantly stirring up material as it falls off the straw walkers.

Each set of discs is powered by a separate hydraulic motor.  It takes about the same amount of energy to run the pin mills as the original chopper. The mills run at 1,200 rpm's.