A coffee roaster is an oven with a roasting drum. The roasting drum turns on a horizontal axis within the oven to tumble coffee beans while roasting and to even out differences in heating. The roasting drum is fitted with a bearing journal at each end and just fits within the length of the oven. Opposite ends of the oven have four rollers each that receive the turning weight of the roasting drum by riding along the bearing journals. Each roller wheel is carried at the distal end of a rocker arm attached by its near end to the lower end wall of the oven below a corresponding drum opening. Each in a set of four roller wheels are height adjustable at the 4-o'clock, 5-o'clock, 7-o'clock, and 8-o'clock positions. The two outer rockers and wheel rollers adjust the lateral position of the roasting drum in the oven, and the two inner ones adjust the vertical height of rotation within the oven.