I,m building a machine as Jazz knows, that is able to take a half sheet ie 1220mm x 1220mm. My x is going to be 1700mm, y is going to be in the region of 1670mm/1700mm, and z will be finalised nearer the time, but will have travel of 100mm. The sides of my table will 250mm high, and the removable table will be sitting 100mm down from the top of the sides. When i have my 200mm material on the machine, my z travel is going to be in the region of 50mm (nothing is finalised at the moment apart from the table design). When i have thinner material on the machine, and the removable table is fitted, again, the travel will be 100mm. I,m hopeful that this will be in keeping with the strength of the machine, which i,m sure it will be. i,m looking at using 350mm of the over hang for the 4th axis. The way i,m doing as advised, is to keep it out the way of normal table operation, and this design is going to do just that. Just need to get the bloody workshop built, hopefully this weekend, now that the snow is away AGAIN.