Slate-mak′ing ma-chine′.
Fig. 5153 is a machine for grinding and polishing school-slates. The slates are supported on cars G, which are connected by arms with a vertical shaft, by which they are caused to move slowly around in a circular track, having a series of inclines. The distance apart of the corresponding parts of each similar incline is exactly equal to that between the front and hind wheels of the car, which is thus caused to remain perfectly level as it rises to present the slate to the grindstones D, and falls during its forward movement.Machine for dressing slate-frames. |
Machine for grinding and polishing school-slates. |