Abstract: A milling machine for producing toothed wheels has a workpiece receiver for receiving a workpiece to be toothed, which workpiece receiver can be pivoted relative to a machine frame about a workpiece pivot axis. To produce the tooth system, two machining units with two tool spindles are provided to receive milling tools. A first tool spindle can be moved linearly relative to the workpiece receiver in at least two directions and can be pivoted about a spindle pivot axis, which runs parallel to the workpiece pivot axis. A second tool spindle can be moved linearly relative to the workpiece receiver in at least two directions. The milling machine has high manufacturing productivity and flexibility and, in particular, also allows the production of tooth systems with an uneven number of teeth.

Abstract: During the assembly of a gas circulation block, encased in sheet metal, a conical sheet-metal sleeve is placed onto a shaped block which is in the form of a truncated cone and made of a refractory material, then a sheet-metal cover provided with a gas supply tube is laid onto the larger end face of the shaped block and then the sheet-metal sleeve is welded onto the sheet-metal cover. In order to reduce the assembly effort and at the same time to create an improved gas circulation block, the conical sheet-metal sleeve is heated up before placing onto the shaped block and is then shrunk onto the shaped block. By the shrinking of the sleeve, every type of dimensional inaccuracy is compensated for, whether on the shaped block or on the sheet-metal sleeve, so that the sheet-metal sleeve, in the shrunk-on condition, sits uniformly and tightly against the shaped block over its entire periphery and its entire length.