Lead screw pitch on D3/840

Howdy
I put together the 840 / 3rd generation, on the first use it went quite fast, but constantly lost steps. At first I thought the problem was alignment, but the third generation is a little better built. It seems to me that it is not so sensitive to alignment, the aluminum profile contributes to good alignment. Now came my attention unit / step ratio. The default step per unit was 533.3332, This did not seem to be correct, as all the axes moved far farther than mechanically possible. The guide says that the lead screw pitch is 3mm, i get 1.5mm or 1.48mm measuring. Does anyone know the exact lead screw pitch on 3rd generation? When I use a step per unit 266.666667 which corresponds to a 1.5mm pitch, in this case all axles are within the limits and I did not detect a fault per 100 mm move. But it would be nice to know what the right number is.