If you are talking about the one Leinback (sp?) makes, it is too light as-is to do much dethatching or scratching. I had one, and had a friend weld some sheet steel and angle iron over the horizontal portion of the tines to make a weight shelf, and then welded diagonal braces from the top link to the outside corners. After that, it would scratch pretty good with about 200 pounds of weight. Don't weld to the tines themselves, they are spring steel and it will ruin the temper and they will bend or break.
I used mine as a dethatcher in my pasture and as a harrow to smooth our riding ring. It would almost work like a landscape rake, but the tines weren't stiff enough. It is a bit more agressive than a purpose-built dethatcher, and the larger tines will pull some good grass up sometimes.
I had a 54" thatcher on my 425 and it did a good job. The swisher estate rakes I think do a better job since they are able to float and follow the ground contour instead of being rigid like my JD was. slkpk