John Deere 12 DISC HARROW

The concave harrow disks pick dirt up for cultivation and also cuts the weeds at the same time.  Two harrow bars are attached to a set of harrow disks with 6 disks in each set. 

Harrow at Heritage Center
John Deere Model “JB” Disk Harrow on retired tractors.com

For more information see the Wikipedia article.

1979.009.016 Harrow, Disk