Originally Posted by
T-Mar
Miele models were built with Columbus, Ishiwata and Tange tubesets. Columbus' butted and spline reinforced steering column employed five helical ridges. Ishiwata's version used five straight ridges, while Tange's version used six, helical ridges. All three, should have external logos, which the OP did not see. It could be a non-spline version or the logo impression could be faint or inadvertently missing. Of the three, a Columbus steerer tube is the most likely to suffer a quality lapse with the logo stamp. Regardless, if it splined, the number and style of the ridges, will identify the manufacturer.
Here are some pics of the inside of the steerer tube.