Abstract: A coordinate measuring machine (10) having a horizontal probe shaft assembly (20) in which a cover system is provided for the X and Y axis ways (46, 108) and carriages (50, 106), including inwardly slanted X-axis cover members (26) mounted atop granite exposed way members (24) defining a gap through which the Y column (88) moves, a pair of upstanding side covers (32) mounted over the Y-axis column (88) defining a gap through which the probe shaft assembly (20) moves in its vertical movement. a recirculating cover belt (28) fills the X-axis gap and pleated upper and lower covers (34, 36) cover the vertical gap lying between the side covers (32) at the front and rear, while a top cap (38) atop side covers (32) and end caps (30) are fit over the X-axis cover members (26), X-axis way members (24) and base portion (18).