Old Wohlenberg 3 Knife Cutter

Hi,

I was wondering if anybody have encountered chipped edges while doing a 3 knife guillotine on the perfect binding manual. I have chipped edges on the right side only but the left side is clean.

We tried changing the blade, lessening the quantity of manual per cut, still the same chipped edges.

We are trying to check if the clamp might have cause the chipped edges?

The manual size before cutting is 181 mm.
The final size that would be cut will be 158 mm.

What is the correct clamp size for this item?
and how thick should the clamp be?

Of if there are other solutions we can try. Please let us know thanks!