The table at maximum Y travel.

At minimum Y travel.

The rubber sheet bunching up between the table and the column is what sets the limit on Y travel.

With the old encoder fitted the table can move about 134.2mm in Y before it starts to crush the sheet enough to be felt through the wheel. Now that it's gone the table can move about 163.9mm before the same thing happens. I've gained 29.7mm of Y travel (22%) by putting the encoder where it should have been, though it still falls slightly short of the 175mm advertised. I expect I could get that last 11mm with a change to the sheet fixing, but it's not worth worrying about right now.

This is a major improvement, especially as I have a 150mm square part to make. Previously I had to make it by doing as many features as I could in one setup, then moving it 40mm or so and trying to reacquire the zero.

There are two ways to refit the rubber sheet. Neither results in much difference in Y travel, so I've gone with the one that doesn't trap chips.