Technical advise Dreis Krump Power Leaf Brake

[Portable Welder]

So I have my new to me 1945 Dreis Krump Brake, Also known as a Power Leaf Brake, it is rated to bend 10' of 3/16" plate, the clamping head is hydraulic operated and leaf or apron is mechanically done with a series of gears.

So my question is: I've gotten conflicting opinions on how far the head should be set back for the material that I'm bending, most people have said 2 times material thickness, so if I'm bending 1/8" I would set it back 1/4" if thats the case, that seems a bit much to me, Just looking at it I think I could go 1-1/2 times material thickness and be fine.

Or is it on a sliding scale of as the material gets thicker you need to go 2 times material thickness for say 3/16" plate,

This type of brake seems to be a bit obsolete for a brake of this size, so I'm having a problem finding anyone who actually operated one of these relics.

[Country Metals]

Just as in hydraulic brakes, the bigger the gap, the easier it will be to bend. This will also cause a larger radius. I would say minimum you could go 1 - 1.5 on alum up to 1/8. 1.5x on 1/8" steel. 2x on everything thicker. The best suggestion I have is to go get steel bent on an hydraulic brake with proper sized dies, then bend some on your brake and you can see how it compares. I would start out bending a piece of 1/8" say 4' long at 2x then go from their.

Just for the record, I beat the balls off of my little tennsmith box and pan and still haven't broken it. Rated for 16ga but I have bent 18" of 12ga stainless on it.

[Portable Welder]

Country metals, I agree but I would like to know what the manufacturer says and finding a manual is not easy to find.