Products › Replacement Knife without Knifehead 40' - Double Drive Image 1 of 1 Replacement Knife without Knifehead 40' - Double Drive $1,216.00 Part #JD2029RKCompatible with: John Deere 640D, 640FD Add To Cart Added! Part #JD2029RKCompatible with: John Deere 640D, 640FD You Might Also Like Knife Kit 9' $1,533.00 Skid Shoe Set 15' x 1/4" $550.50 Outside Snout $41.50 Auger Liner 25' $1,182.00 Knife Kit 12' with Rollers $2,032.00