Abstract: A scale reading apparatus having a dust-proof means for protection of the slide and guide surfaces, the relatively moving parts of the apparatus, from the ingress of foreign material and a means for sensing the scale reading. The dust-proof means includes a flexible band covering the entire length of the slide surfaces and an opening connecting the moving parts. The scale sensing means is resiliently mounted at an angle to the verticle thereby substantially reducing the forces applied and the affects of vibration upon the scale sensing means to insure a high precision reading.