I found my Viel S-5 makes concave edge at the heel of blade. I think it's because the tension of belt is not even i.e. the tention of outside is lower than in the center.
How do you prevent it? I think it's helpful to maintain low pressure, but it doesn't seem to be a complete solution.
How do you prevent it? I think it's helpful to maintain low pressure, but it doesn't seem to be a complete solution.

