Gack HE20 reversed shaper head
The reversed shaper head is a unique piece of equipment special to the Gack shaper - It has some advantages against the standard push type claper box:
The cutting forces are directed against the column of the machine, allowing for a heavier cut
When working to a scribed layout line the burr from the cutter does not interfere with the scribed line, as it is created on the backside of the cut
Chips don't get thrown into the face of the operator
I made a set of drawings and took some photos of the shaper head. Size wise it might work on a small shaper like the Southbend 7" without much modifications, for bigger machines scaling will be necessary.
Gack Reversed shaper head, last version 22.11.2015 PDF Version