Continuous shot-blasting machine

A continuous shot-blasting machine for surface treating arbitrarily arranged batches of workpieces includes at least one blasting chamber for shot-blasting the workpieces and a turn-over device for turning over the workpieces to expose all surfaces for treatment. A pair of supporting racks carry the workpieces along a conveyor to and from the blasting chamber. The workpieces are carried on one of the supporting racks through the chamber for blasting treatment of their exposed surfaces and after being turned over are carried on the other supporting rack through the same chamber or through a second chamber for blasting treatment of the newly exposed surfaces. The turn-over device rotates the first supporting rack and workpieces through 180 degrees about a substantially horizontal axis after the first shot-blasting treatment to turn the workpieces over for deposit onto the other supporting rack. The turn-over device includes electromagnetic or hydraulic members for holding the workpieces on the supporting rack during the turning operation, and for releasing the workpieces from the supporting rack after being turned over to expose the untreated surfaces.