It’s never been specifically explained to me the reason for the side arms being short in height so this is only my thinking as to why a company that thinks things through so well have designed the side arms on the cutters as they have. When you score a
tile you need to have some space for the adjoining cuts to fall into so that gravity is able to do its bit in the breaking of the tiles. We often have our machines resting on surfaces that aren’t necessarily perfectly flat with that in mind the space below the extended side arm allows for tollerance with this issue. We can place a pice of off cut etc under a side arm to adjust its height if nescessary or not what ever that lay if the land dictates. In all my years of using Sigma
tile cutters this is how I’ve thought of this and it works for me. Someone may well come along with an official explanation that dismiss my thinking on it but that’s how I see it and it works for me. Every day is a school day for me so I’ll gladly take onboard any other reasoning for it.