The shape of a Concave blade cuts in such a way it drags the warelayer up which gives a raised sharp edge to the cut and can cause delamination of the product ! Straight blades cut with downward pressure so a nice clean cut with little to no raised edge
Always use sweeney Todd concaves. Have had a box or 2 that seem to snap right at the end and dont last long. Have tried with straight blades but they just seem to slip around a lot. I get what you are saying spacey but I've never had a problem with delimination
I find if you score to hard with a concave then it does what spacey has mentioned but few light strikes and its totally fine. Ive noticed the last few boxes of the Sheffield steel concs I've had have snapped heads pretty easily aswell.
