T-slots, that is.
I’ve never had a tool with t slots, just ordinary miter slots. I’m very quickly thinking that t slots are a major design flaw, not a feature.
I never had a problem keeping a bar in a miter slot without the tee. But I find that sawdust and detritus in the slot make the bar stick, way too much. A square slot gets swept out by the bar, but the tee just jambs it in here. I’m thinking about just taking off the washer on the bottom of the bar that creates the tee.